NASA Contractor Report 17 8079

NASA-CR-178079

19860014923

Modifications To The 4 x 7 Meter Tunnel

For Acoustic Research

Engineering Feasibility Study

I •

DSMA Engineering Corporation

Orlando, Florida

Contract NAS1-17 892

March 1986

NI\SJ\

National Aeronautics and

Space Administration

Langley Research center

Hampton,Virginia 23665

r.

!13RARV COpy

APR 2 8 1Yb6

LJ\NGLEY RESEARCH CENTER

LIBRARY, NASA

HAMPTOfJ, VIRGINIA

71 CATEGORY : :.

f',!AS1-17892

ISSt5E 14

1.26:178079 REPT-4054/R128

{JTiL: to "T~.__-"".

~_:. :.~ 4x7 rneter aC~)~lst i c

-feasibility studY TLSP: Flnal Report

LOW SPEED STA8iLiTY/

AIRCRAFT; SHORT TAKEOFF AIRCRAFT

HiJtrlc-r

TABLEOF CONTENTS

__ Page

. I. INTRODUCTION 1

1.1 General 1

1.2 Scope of Work 2

2. CONCEPTUAL STUDY 4

2.1 Fan Redesign 4

2.1.1 Circuit Loss Estimates 4

2.1.2 Fan AerodynamicDesign 6

2.1.3 Mechanical/StructuralConcepts 11

2.2 Settling ChamberAcoustic Treatment 20

2.2.1 Concept Development 20

2.2.2 AerodynamicConsiderations 22

2.2.3 ProposedConcept 23

2.3 Test Chamber AcousticTreatment 24

2.3.1 TreatmentConcept 24

2.3.2 Installationand Removal 26

2.4 Turning Vanes AcousticTreatment 28

2.4.1 AeroacousticConsiderations 28

2.4.2 StructuralConcept 29

2.5 Relocation of Control Room 30

2.6 Sting and Rotor Drive 32

2.6.1 Sting Support System 33

2.6.2 Rotor Drive System 35

3. COSTESTIMATES 39

3.1 General 39

3.2 Cost Estimate 41

4. PROJECT SCHEDULE 42

t

5. CONCLUSIONS 43

i
TABLEOF CONTENTS(Continued)

Page

REFERENCES 44

TABLES 45

FIGURES 57

DRAWINGS 63

±i
LIST OF TABLES

._ Table 1 Losses.Existing Circuit,Power Point

a) Closed Test Section

, b) Open Test Section

Table 2 Lbss Summary, Existing Circuit

Table 3 Losses, ProposedCircuit

a) Closed Test Section,Power Point

b) Open Test Section,Power Point

c) Open Test Section,AcousticDesign Point

Table 4 Loss Summary,ProposedCircuit

Table 5 Comparisonof Existing and ProposedFan

Geometries

Table 6 Losses. Proposed Circuit,OriginalSettling

Chamber Area

a) ClosedTest Section

b) Open Test Section

Table 7 Comparisonof AcousticTurning Vane Concepts

iii

LIST OF FIGURES

. Figure I Scheme B (SignificantFan Redesign)

AcousticTreatmentof the 4 x 7 m

. Tunnel Circuit (fromReference3)

Figure2 ApproximateFan Performance

Figure 3 Fan Blade InterferenceDiagram

Figure 4 Project Schedule - Construction

v

LIST OF DRAWINGS

DRAWING NO. SHEET TITLE

3

LD - 544301 1 Key Diagram for ProposedModifications

LD - 544302 1 Fan Assembly - Initial Concept

LD - 544303 1 Fan Assembly - ProposedConcept

LD - 544303 2 Fan Rotor/Blades- ProposedConcept

LD - 544303 3 Fan Drive - Coaxial Gearbox Concept

LD - 544304 1 AcousticTreatment - SettlingChamber

LD - 544305 1 New Control Room Layout

LD - 544306 1 AcousticTreatment - Test Chamber

LD - 544306 2 AcousticTreatment -Test Chamber

LD - 544307 1 AcousticTreatment-Turning Vanes

LD - 544308 1 Rotary Sting Arrangement

LD - 544308 2 No. I Rotary Joint

LD - 544309 1 Rotor Drive AssemblyConcept

LD - 544309 2 Rotor Drive Gearbox Concept

vii

Page 1

1. INTRODUCTION

1.1 General

The NASA-LangleyResearch Center 4 x 7 meter Low Speed Wind Tunnel

_. is currently being used for low speed aerodynamics, V/STOL

aerodynamics and, to a limited extent, rotorcraftnoise research.

The deficienciesof this wind tunnel for both aerodynamics and

aeroacousticsresearchhave been recognizedfor some time. Within

the FY-1984 NASA Construction of Facilities (C of F) Program,

modificationsto the wind tunnel are being made to improve the

test section flow quality and to update the model cart systems.

A further modificationof the 4 x 7 meter Wind Tunnel to permit

rotorcraft model acoustics research has been proposed for the

FY-1989 C of F program. As a precursor to the design of the

proposed modifications, NASA have conducted both in-house and

contracted studies to define the acoustic environmentwithin the

wind tunnel and to provide recommendationsfor the reductionof

the wind tunnel background noise to a level acceptable to

acoustics researchers. One of these studies by an acoustics

consultant,Bolt, Beranek and Newman Inc. (BBN),has producedthe

primary referencedocuments (Referencesi and 3) that define the

wind tunnel noise sources and outline recommendedsolutions.

As wind tunnel design consultants, DSMA Engineering Corporation

has been retained to conduct a conceptual design and feasibility

study for the practical application of the modifications

recommendedin References1 and 3. This reportcovers the results

; of the study.
Page 2

1.Z Scope of Work

The work is defined in NASA Specification No. 1-14-5627,0236

(Reference2) and covers the followingareas:

- Redesignof the fan to achieve,as a goal, fifty (50) percent

fan rotationalspeed reductionat the operatingpoint.

- Structural considerationsto enable installationof acoustic

treatmentin the settlingchamber.

-Acoustic treatmentto the test chamberwalls,ceilingand

floor.

- Acoustic treatmentto the turning vanes in corners 1 and 2.

The modificationslisted above represent"Scheme B" recommendedby

BBN in Reference 3 and adopted by NASA for the purpose of this

study. The areas of the wind tunnel included in the Scheme B

modificationsare shown schematicallyin Figure 1.

The scope of work also included two areas closely connected with

acoustictesting.

- Relocationof the control room outside the test chamber.

- Conceptualdesignof a new Sting and Rotor Drive System.

The overall layout of the 4 x 7 m wind tunnel and of the areas

covered by the study, is indicated on Drawing LD - 544301.

In each of these areas it is requiredto develop a feasible design

concept, consider its implementationand prepare preliminarycost

estimatesand preliminaryschedule.
Page 3

The developmentof suitabledesignconcepts must take into account

the following additional requirementsimportant to the facility

users:

- The down time of the wind tunnel necessaryfor implementation

of the modificationsshould be minimized.

-The acoustic treatment on the test chamber floor and the

undersideof the movable ceiling of the test section, should

be removable. This will enable the facility to be converted

from acoustic to aerodynamic testing mode and vice versa.

The facility down time necessary to accomplish such a

conversion must be the shortest possible; one day (two

shifts) durationwould be desirable.
Page 4

2. CONCEPTUALSTUDY

2.1 Fan RedesiBn

The basic requirementsfor the fan redesignwere that when the BBN

"Scheme B" (see Figure 1) was implemented,the existing circuit

design points would still be achievable. These design "power"

points are, for the closed and open test section configuration,

120 and 70 psf dynamic pressure respectively. In addition, an

"acoustic" design point with a dynamic pressureof 50 psf in the

open test section should be achieved at reduced (halved as a

design goal) fan rotational speed, compared to the present

situation.

In the present work, no allowancehas been made for models in the

test section or for the losses associatedwith the air exchange

system (outlet upstreamof corner 3 and inlet in the test section

diffuser). Estimates of these losses should be included in the

final evaluationof circuit performance. Further, since the air

inlet is in the test section diffuser,the static pressureat this

point will be slightly sub atmosphericand this will modify the

circuit pressure levelsgiven in Tables 1, 3 and 6.

The fan redesign procedure in this study included definition of

the fan design parametersby calculatingthe circuit losses, fan

aerodynamic design, and development of mechanical/structural

concepts.

2.1.1 Circuit Loss Estimates

The operating conditions in terms of the total pressure rise and

the mass flow for the fan on which the redesign was based were

defined by calculating the circuit losses. All circuit losses

were calculated using a DSMA proprietarycomputer program. This

program has been used for the design of a variety of closed return

circuit wind tunnels covering a wide range in speed (low subsonic
Page 5

to Mach 1.4), test section size (1.5 to lOOm2), and test section

type (closed and slotted wall, and semi-open and open jet); and in

all cases where it has been possible to compare the design

., calculations with measurementsin the facility,they have agreed

welI.

As a first step, the losses and fan requirementsat the two power

points were calculatedfor the circuit as it has existed to date.

Geometricdata was taken from Sanders and Thomas Inc. Drawing No.

LD-254369 (March 67), and it was assumed that two 1.0 q screens

had been installed in the settling chamber upstream of the

contraction. The detailed loss outputs for the two cases are

given in Table 1 - part (a)gives the resultsfor the closed test

section case and part (b) gives those for the open test section.

Since informationon the existing fan was not available,the fan

efficiencieswere estimatedby dividingthe "air power" from the

loss calculationsby the maximum drive power of 8,000 hp.

The results for the existing circuit are summarized in Table 2.

The closed test section results were compared to detailed

experimental data supplied by NASA Langley, and found to be in

reasonableagreement. Similar data for the open test section were

not avaiIable.

The second step was to estimate the losses for the proposed

circuit (BBN Scheme B). For this analysis,several modifications

were made:

/i

-The loss factors for the turning vanes in corners 1 and 2

° were increased. As discussed in Section 2.5.1, a decision

was made to use rolled plate turning vanes with acoustic

" treatment on the inner (pressure)surface as incorporatedin

the DNW tunnel. The loss increment used was based on

experimentaldata from DNW, Reference4.
Page 6

-The cross-sectional area of the "settling chamber" (from

corner 3 inlet to corner 4 outlet) was reduced under the

assumptionthat 0.61 m (2 ft) thick acoustictreatmentwould

be internallymounted on the floor, sidewalls, and roof of

this section of the wind tunnel. As discussed in Section

2.2.2, the reductionin facility performancedue to this area

decrease is predictedto be minimal.

- Flow conditioningdevices are being installedin the facility

to improve the test section flow quality as part of the

current program of facility upgrading as described in

Reference 5. Lossesfor these components- 2.0q for the grid

upstream of corner 3 and 4.3q for the honeycomb and four

screens in the settlingchamber (downstreamof corner 4) were

incorporatedin the analysis.

- For the open test section cases, the nozzle area was reduced

to account for the 0.61 m thick (2.0 ft) acoustic treatment

on the floor of the test section.

With these assumptions, losses were estimated for all three

operating conditions defined earlier. The fan efficienciesused

were the resultsof the ongoing fan design analysis. The detailed

loss outputs are given in Table 3 - parts (a) and (b) give the

results for the "power" point conditions in the closed and open

test sections respectively,and part (c) gives the results for the

open test section, "acoustic"design condition. The results are

summarized in Table 4, and are the basic input data for the

aerodynamicdesign of the fan.

2.1.2 Fan AerodynamicDesign

The principalobjective of the fan redesignwas to minimize the

RPM at the 50 psf operating point in the open test section

configuration. The nominal goal was half the speed from the 185

RPM currently required.
Page 7

As seen from Table 4, the lowest mass flows and highest fan

pressure ratios occur for the open test section configuration.

Since these operatingpointswill thus be closest to the fan surge

line, they representthe critical conditions for the fan design.

• The first step in the design process was thereforeto select the

lowest possible RPM which still gave an acceptablesurge margin at

the 50 psf point. A check was then made that stable operation

would be available at the 70 psf open test section point.

Finally, an estimate was made of the RPM needed at the 120 psf

closed test section point, since this defines the maximum speed

needed from the fan drive.

In additionto havingthe performanceobjectivesdescribed above,

the new fan was subject to several aerodynamic and mechanical

constraints.

In the first place, it was agreedwith Langley personnelthat the

fan should be of conventionaldesign. Essentially,this involves

keeping the fan geometric parameters within the range for which

cascade data are available. In this way it will be possibleto

predict the pressure ratio, surge margin and efficiency of the

final design with a high degreeof confidence. By comparison,an

unconventionaldesign would involve considerable risk and could

necessitate expensive model tests. The main constraint arising

from these considerationsis a maximum blade solidity (chord/blade

spacing)of about 2.0 at the hub.

The new fan was not to compromisethe aerodynamicsof the rest of

° the circuit, particularlythe stabilityof the fan diffuser. It

was found necessary to reduce the fan cross-sectional area in

• order to obtain a sufficiently high flow coefficient (axial

velocity/bladespeed), and this in turn increasedthe area ratio

of the fan diffuser. The fan diffuser performancewas therefore

analyzed in parallelwith the developmentof the fan design. The

analysisshows that the diffusercan cope with the 7 m (23 ft) hub
Page 8

diameter of the new fan, particularly since the flow uniformity at

the diffuser inlet should be better than at present,

Finally,the new fan should require as little modificationof the

existing structure as possible. Specifically,the new stators

should if possible accommodate the main fan supports which

presentlypass through three of the seven stators. This objective

has been met and the new stators should simply call for the

reskinningof the presentones.

The detailed fan geometry is given in Section 2.1.3. The present

section describesthe method used to predict the fan performance,

outlines the aerodynamicrationalefor the geometry selected and

presentsthe estimatedperformancediagram.

The requirementsin this particularcase necessitateda departure

from the usual DSMA fan aerodynamicdesign procedures. Normally,

no attempt is made to predictthe off-designperformanceuntil the

blade angles have been selected during preliminarydesign. The

geometry is then run through the streamline-curvaturecomputer

program which predicts the complete performance map, including

efficiencies, using cascade correlations. Such detailed

calculations are beyond the scope of a feasibility study. The

off-design performance has therefore been calculated using a

simpler, and necessarilymore approximateprocedure.

Briefly, the method consists of a through-flowcalculation based

on simple radial equilibrium neglecting entropy gradients and

density changes. To predictthe off-designturning performanceof

the rotor blades it is assumed that the outlet relative flow °

direction is the same as at design and thus, the change in

deviation angle with incidenceis neglected. This simplification

causes least error near the design point and for this reason the

design point was placed close to the critical open test section

operating points.
Page 9

Since the fan inlet flow is known to be non-uniform,this was

taken into account in an approximateway by specifying a linear

inlet axial velocity variation,with hub and tip axial velocities

120% and 80% of the mean respectively. No attempt was made to

vary the degree of non-uniformitywith the mass flow rate or as

• the hub-to-tip ratio was adjusted. Finally, no attempt was made

to predict losses. The total enthalpy rise obtained from the

through-flow calculations was translated into pressure ratio by

assuming an isentropicefficiency. A conservativevalue of 85%

was used at the design point and it was adjusted downward at

off-designcalculationpoints.

To achieve maximum performance,the new fan rotor uses the maximum

allowable solidityof 2.0 at the hub. However,it was found that

the rotor performancenow availablecould not be fully exploited

because the stators would be unable to remove the swirl. Using

the same chord length as the existingstators,the solidity at the

stator hub is already about 2.6 and it was therefore undesirable

to try to reducethe loading by increasingthe solidity. Instead,

a set of inlet guide vanes was added to give the rotor inlet flow

30 degrees of prewhirl. This has the effectof reducingthe flow

straightening through the stators to about 30 degrees, which

should be achievable with reskinned versions of the existing

stators. A comparisonof the basic geometryof the existingand

proposedfan is given in Table 5.

As configured, the three blade rows of the new fan are about

equally loaded and two of them are at the allowable geometric

limits. There is therefore little scope for further increasesin

- performance. The proposed configuration essentially represents

the best that can be done in a single-stagemachine.

The approximateperformancemap for the new fan is shown in Figure

2. It will be noted that the open test section load line lies

quite close to the surge line. The occurrence of surge was

predicted from a criterion usually employed by DSMA, namely when
Page i0

the diffusionfactor (a parameterwhich quantifiesblade loading)

reaches 0.6 at any point or 0.4 at the rotor tip. These are very

conservative values for a low speed machine. In addition,it may

be possible to increase the surge margin slightly during final

design, by the choiceof an alternativefan design point and with

other minor modifications. There is therefore no doubt that •

stable operation will be available, with a reasonablemargin of

safety at the points in question.

As seen from the map, 135 RPM will be needed at the 50 psf

operating point, whereas the goal was 93 RPM. As outlined

earlier, the performanceobtained from the new fan is the best

that can be achieved in a single-stagemachine of conventional

design. In short, the 93 RPM goal is not feasible. As to the

precise speed needed, the approximate nature of the off-design

calculations should be borne in mind. When the design is refined

and more accurate performancecalculationsmade, some adjustment

in the speed is likely, but at best only a marginal reductionin

RPM can be expected.

Although an assessmentof the noise characteristicsof the new fan

was beyond the scope of the present study, the followingobservations relativeto acousticdesign of the fan are pertinent.

The DNW wind tunnel, which has a well known excellent acoustical

environment,has a fan of very similar diameterto that of the 4 x

7 m wind tunnel with a top speed of about 200 RPM correspondingto

an open test section velocity of 85 m/s (about 90 psf dynamic

pressure)for the 6 x 8 m nozzle. It thus seems certain that at a

given test section dynamic pressure, the proposed fan will be

running at a considerablylower tip speed than the DNW fan.

The new 4 x 7 m wind tunnel fan should be designed with noise

reduction in mind and due consideration must be given to such

questionsas the spacing between blade rows in order to reducethe

strength of the blade-wakeinteractions. This, together with the
Page 11

fact that the new fan will be running unstalled,should make it

inherentlyquieter than the existing one. Finally,since the new

fan will require a new nosecone,nacelle and tailcone,it would be

. a relativelyeasy matter to incorporateacousticaltreatment both

upstream and downstreamof the rotor (as, for example, in NTF).

2.1.3 Mechanical/StructuralConcepts

The key considerationin this portionof the study was to develop

a feasible mechanical/structuralconfiguration that can be

implementedat a reasonablecost.

Based on the aerodynamicconsiderationsdiscussedin the previous

section, a fan geometry was established together with the

followingdesign goals aimed at minimizingthe costs.

- Retain the fan section outer casing with a diameter of

approximately 12. 5 m (41 ft), and modify the casing as

required.

- Retain the fan foundation;that is, the location and general

size of the fan stator vanes.

- Modify the fan drive system to develop approximatelythe same

power as at present but at reducedspeed.

- Replace fan nacelle,nosecone and tailcone.

- Replace fan rotor and blading.

The recommended fan geometry can be seen on the Drawing LD -

; 544302. Compared to the present design of the fan, several

changes may be noted.

The nacelle diameter has been increasedfrom 4.9 to 7 m (16 to 23

ft) and the length has also increasedat the tailcone (downstream)
Page 12

end. The short spinning nose cone has been replaced by a

stationary semiellipticalassembly with an aspect ratio of 2:1,

supportedby five (5) inletguide vanes. The fan rotor remainsin

its original locationwith its center at station 351'-3" but it is

wider than at present to accommodatenineteen (19) large chord

rotor blades.

The stator airline profiles will be modified; however, the

structural "columns" supporting the fan housing at 8 discrete

foundationbase plates are unchanged.

Several importantcomponents and aspectsof the fan redesignwere

considered in more detail and are discussed in the following

sections.

2.1.3 a) Fan Blades and Rotor

The fan blades have the following basic configuration

developedin the aerodynamicconcept work:

Number of blades : 19

Hub solidity : 2

Ratio of tip/hub chord : 0.75

Taper (chordwiseand

spanwise) : linear

Thickness - hub : 12% of local chord

- tip : 8% of local chord

Blade Profile : NACA 65 Series,

CircularArc Camber

These values are preliminary and are likely to change

somewhat during later design phases.

The relativecost, durabilityand inherentstructuraldamping

of simple, solid wood blades make this construction preferable, if feasible. DSMA has had many years of successful
Page 13

experiencewith operationof such blades,and design/constructionmethodsare welldevelopedand proven.

o A layout of a typical blade geometry and root attachmentis

shown on Drawing LD - 544303, Sheet 2. The blade is

, laminated, usually from Sitka spruce. In the spanwise

directiontoward the root, wood impregnatedby phenolic resin

(Compreg) is gradually laminatedbetween the spruce sections

so that at the root, the full section is made of Compreg.

Also, the airfoil shape is changed into a cylindrical root

section by a gradual transition, with the portions of the

chord overhungoutside the root section being lightened. The

airfoil section is covered by a thin layer of fiberglass,and

the leading edge is protectedby a metal (Monel) strip. A

pine breakaway section is installed at the blade tip. A

steel ferrule with a clamping ring is fastened to the root

section,for attachmentof the blade to the rotor.

The fan rotor is shown on the Drawing LD - 544303, Sheet 2.

It is a steel weldmentconsistingof a central hub, two discs

and radial ribs. Blade ferrules fit in sockets at the rotor

circumference and the sockets are connected to the rotor

discs by means of short shear tubes.

The blades are fastened in the rotor sockets using clamping

rings and high strength bolts. Fairing plates then cover the

socket openings as shown on the drawing. This blade attachment design is safe and reliable,and has been proven on a

number of low speed wind tunnels. The design also allows

- small adjustmentsto the setting angle of the blades and this

feature can be used to optimizethe fan performance.

The fan blade design was checked by a preliminarystress and

vibration analysis. The stress analysis considered the

centrifugal and aerodynamicbending loads, and the maximum

combined stress at the root was found to be 1.8 Ksi. In the
Page 14

final design, the blade will be tilted to reduce the

aerodynamic bending loads so that the maximum stress will

decrease. The allowablefiber stress for Compreg is 7.5 Ksi

for "infinite" life and therefore, the blade stresses are

well within the allowablelimits.

Another important aspect of the blade design is the blade

vibration. A DSMA blade vibration program was used to

calculate the natural frequencies of the baseline blade

geometry. The results in the form of a Campbell (interference) diagram are shown in Figure 3. The first two

natural frequencies are plotted as a function of the

operating speed, with cross-plotted excitation orders

(so-calledengineorders). This initial evaluationwas made

without any attempt at optimizationof the blade design; it

may be seen that there is a possibilityof a resonanceat

close to 130 rpm as a resultof excitationof the rotor blade

by the pressure field upstreamof the stator vanes. Another

possible resonancemay occur at close to the top speed (180

rpm) due to excitation by the wakes from the inlet guide

vanes.

During the design phase, the fan will be optimized to avoid

potential resonances at high speeds as they could lead to

blade failures. This optimizationis normally accomplished

by changing the blade section design to alter the natural

frequencies, by changing the excitationorders (e.g. number

of guide vanes), or by a combinationof the two.

As a result of the analyses and previous experience,it is °

concluded that it will be feasible to design solid wood

blades for the new fan.

There are several wood blade manufacturersin the USA and in

Europe. During this study, DSMA contacted two of them, to

discuss feasibility and obtain pricing of the blade set.
Page 15

These discussionswill be continuedduring the design phase.

An alternativeapproachwill includeconsiderationof hollow

blades made of composite materials. The fabrication

technology in this area is progressingvery rapidly and it is

conceivablethat, in the future, the composite blades may be

• less expensivethan wooden blades. Hollow blades also offer

the potentialfor increasingthe naturalfrequencieswhich is

desirablefrom the point of view of vibratory stress levels.

On the negativeside, hollow blades are more susceptibleto

foreign object damage and repairs are more costly.

2.1.3 b) Fan Drive System - Initial Concepts

The redesignedfan will absorb approximatelythe same power

as at present (closeto 8000 HP) at 158 rpm, about two thirds

the present rotationalspeed.

A completely new drive system was quickly evaluated but the

costs would be prohibitive.

The existing drive system consisting of an AC synchronous

machine in tandem with a smaller DC drive cannot be modified

electricallyto providethe requiredperformance. Therefore,

a gear reducer appearsto be the only effectiveoption. DSMA

contacted three suppliersof 'standard'gear reducerswith a

request for configurationand pricing. All three companies

(American Lohmann, Falk Corp., and David Brown Co.) offered

their standard line, single stage gearboxeswith an offset,

despite requestsfor a coaxial design.

The drive layout shown on Drawing LD-544302, incorporates

• such a gearbox. It is clear that as a resultof this gearbox

design, the implementationof the fan redesign becomes more

complex than desired:
Page 16

- fan drive unit must be raised by the amount

of the gearbox offset,

- an additional bearing must be added to

support the rotor as it cannot be overhung

on the gearbox ouput shaft.

These complications bring into focus the work required to

modify the fan, and the downtime connected with this

activity.

2.1.3 c) Rebuildin9 the Fan - Initial Concept

The new geometry of the fan and the drive system modifications discussed above will require a substantial amount of

work, and entailsome risks.

The fan blades and rotor will have to be removed,and all the

services to the drive train disconnected. This will be

followed by adding new stiffenersand braces whose purpose is

to minimize the amountof distortionof the fan housing. An

upper portion of the outer casing will be removed,together

with the upper stator vanes. Then the nacelle and the drive

assembly will have to be removed through the opening in the

outer casing. When the lower stator vanes have been modified, the new nose cone and nacelle will be erected, the

drive unit with the new gearbox and fan rotor re-installed,

new upper stator vanes welded in and the outer casing closed

up and re-welded. Finally,the fan blades will be installed

and the drive system re-connectedprior to the start of the -

fan tests.

This overall procedure can be described by few sentences;

however, in realitythe constructionwill be difficult,time

consuming and expensive.In addition,the extensiveamount of

cutting and re-weldingon the 1 inch thick outer casing plate
Page 17

will likely result in large distortions. It may then be very

difficult or even impossible to bring the casing shape to

within the limits acceptablefor the runningtrack of the fan

° blades.

" Therefore, this concept althoughconsideredfeasible,was not

satisfactory and work continued on development of a more

suitableconcept.

2,.1.3 d) Fan Drive S_,stem- ProposedConcept

The disadvantagesof the 'standard'offset gearbox approach

resulted in an in-house developmentof another approach - a

coaxial gear reducer built within the fan rotor assembly.

This compact unit is laid out on Drawing LD - 544303, Sheet

3. It is of a solar gear type which has a central sun gear,

4 planets meshing with and spaced uniformly around the sun,

and a ring gear meshing with the planets. The sun gear is

stationary and is mounted in a rigid support able to resolve

the reaction torque. The ring gear as the input member is

doweled and bolted to a heavy sleeve mounted on the existing

shaft of the drive unit using the same mounting as the

present fan rotor. The total transmittedtorque is divided

among the planet gears mounted on needle bearings and heavy

precision ground shafts in a planet carrier which is the

output member.

Since the torque is divided among 4 planets the size of the

gear tooth is approximately 4 times smaller than in a

- standardgearbox, enablingdesign of a compact unit that will

easily fit on the existingshaft.

The fan rotor will be mounted on heavy Timken or Torrington

tapered roller bearings with all the loads being transfered

to the drive motor shaft.
Page 18

Lubricationand cooling of the gears is done by splashingand

a forced feed lubricationsystem, employinga self-contained

lubricatingunit.

In designing a planetary gearbox of this kind, particular

attentionmust be directedto the followingdesign issues:

- high bearing loads on the planet pins; high capacity

needle bearings or roller bearings (space permitting)

will be used, mountedon precision-groundshafts.

- balance and vibration of the rotating cage; high

precision and tight tolerances will overcome this

problem.

- load sharing between planets; a free floating sun gear

will be considered to help ensure equal load

distributionamong the gear meshes.

- epicyclic gears require high accuracy and precision;

therefore, heat treated alloy steel gears will be

employed, the planet and sun gear will probably be

carburized,surface hardenedto 60 Rc and then ground to

quality class AGMA 10, and the ring gear through-hardened to 36 Rc.

- noise generatedby the gearbox (andthe fan drive motor

assembly); the noise level estimates will have to be

made, and necessaryinternal acoustictreatment defined

in the design phase.

DSMA has performed a preliminary design analysis of the

gearbox arrangement. The stress levels in the gears and

planet gear shafts are well within the acceptablelimits (20

Ksi was considered as the limit for this conceptual design
Page 19

stage), and bearings with the required static and dynamic

capacitiesare readilyavailable.

- The detail design may result in some changes mainly due to

lubrication requirements, and detailed consideration of

" component sizing and manufacturing. The lubrication unit

will be located inside the fixed nose cone as shown on

Drawing LD - 544303, Sheet 1.

The design of a coaxial planetarygearbox integrated in the

fan rotor assembly is feasible and is also very advantageous

for the fan redesignconsidered in this study.

2.1.3 e) Fan Housin9 - ProposedConcept

With the successful solution to the fan drive problem, a

suitable concept for the fan housing redesign logically

foIlowed:

-The fan drive unit can remain essentiallyin the same

locationas in the existingfan.

- It should not be necessaryto removethe existing (small

diameter)nacelle.

- Consequently,there is no need to cut open the fan outer

casing, and the risk of distortionduring refabrication

is eliminated.

- The proposed fan layout based on this concept developmentis

shown on Drawing LD - 544303, Sheet 1.

The fan drive unit is not disturbed and neither are the

services to the unit. The existing nacelle is modified by

removing the tailcone downstreamof the drive unit and by

addingstiffenersand mounting brackets.
Page 20

The new nacelle and tailcone is a "fairing"of a lightweight

construction, fastenedto the existing "structural"nacelle.

This lightweight construction will probably incorporate

additionalacoustictreatment as required,to reduce both the

external and internal (drivesystem) noise. °

The same applies to the stator vanes, and the new nose cone

assembly.

The new fan rotor/blade assembly is mounted on the drive

shaft through the coaxia-I planetary gear reducer. The

lubricating unit for the reducer is mounted inside the nose

cone.

This concept is considerablysimpler and more economicalthan

the one initially considered. Very little structural

modificationof the fan housing is required. New components

can be tailor-made in sections based on the "as built"

measurements of the existing fan thereby reducing the

installationtime and the fitting problems. Access into the

wind tunnel shell can be made relatively easily during the

construction through the upstream transition for the nose

cone, rotor and blades, and through the fan diffuser for the

nacelle,tailcone and statorvane fairings.

The cost estimatesin Section 3 are based on this concept for

the fan and fan drive redesign.

2.2 Settlin 9 ChamberAcoustic Treatment

2.2.1 Concept Development

The "settlingchamber" structure is not unlike a large building

made of structural steel. The floor is reinforced concrete.
Page 21

External steel columns and beams suitably braced,support the roof

trusses. The airflow surfaces on the walls and ceilings are

formed by corrugated steel sheeting fastenedto the inside of the

- steel structure.

• Reference 1 recommendsthat the settlingchamber be lined by 2 ft

deep "bulk absorber treatment" without changes to the airline

dimensions. The treatmentbasicallyconsistsof perforatedsheet

at the airflow side and 2 feet of mineral wool or fiberglass.

The requirementto preservethe existing airline dimensionsmeans

that the corrugated steel sheets must be replaced by the flat

perforated sheets of the acoustic treatment,with the corrugated

sheet relocatedto the outside flanges of the structure.

Clearly,this task will be lengthy and expensivefor the following

reasons:

-The corrugated sheet will have to be removed and presumably

not all of it can be re-used.

- Additionalstiffenerswill have to be providedto supportthe

more flexible perforatedsheet on the airflow side, and to

create an effective grid of panels to be filled with the

insulation.

- With the outer corrugated wall completed, the acoustic

insulation material will be installed in :the non-standard

"panels"followedby installationof the perforatedsheets.

.

Since this recommended solution has severe cost and schedule

deficiencies, an alternative approach was considered that would

place the acoustictreatmentinsidethe existingsettlingchamber.

An analysis of this approach and potentialperformancepenalties

is discussedin the next section.
Page 22

2.2.2 AerodynamicConsiderations

The efect on wind tunnel performanceof mounting the treatmenton

the existinginner surface of the settlingchamber shell, and thus

reducingthe flow area in this section,was investigated.

Loss calculations described in Section 2.1.1 above were also

performed for the closed and open test section "power point"

conditions with the settling chamber area as it has existed to

date (the area reduction due to mounting 0.6 m (2 ft) thick

acoustic treatment on the floor, sidewalls, and ceiling of the

settlingchamber is on the order of 12%).

The detailed loss outputs for these two cases are given in Table 6

- the results for the closed and open test section configurations

are given in the (a) and (b) parts respectively.

Comparison of these results with those of Table 3 (a) and (b)

shows that the differencesare extremelysmall - well within the

accuracy limitsof the calculations. This is due to the fact that

the settling chamber cross-sectional area is large compared to

that of the test section, and the losses in this section of the

wind tunnel are quite small - on the order of 1.5 and 0.5% of the

total circuit losses for the closed and open test section

configurationsrespectively. Thus, small changes in this section

of the wind tunnel have a small effecton the total losses.

Based on these results, it was concluded that the acoustic

treatment in the settling chamber can be mounted on the inner

surface of the existing shell. The resultantnegative effect on

facility performance is minimal, if not negligible; but the

positive effects on ease of installation and cost of this

treatment are significant.

There is very little space between the outlet from corner 4 and

the honeycomb in the settling chamber. Care will have to be
Page 23

exercis'edin fairing out the acoustictreatment in this region to

avoid an adverse effecton flow quality.

- 2.2.3 ProposedConcept

• The basic concept of the acoustic treatment in the settling

chamber is shown on Drawing LD - 544304. The acousticmaterial is

placedon the inner surfacesof the existingsettlingchamber in a

form of 0.6 m (2 ft) deep flat panels. The design and

constructionof the flat panels are standard and will be also used

for the sound attenuationin the test chamber.

Mineral wool or fiberglass (density 4 Ib/ft3) is used as an

acoustic material, filling a galvanized steel enclosure. At the

side facing the airstreamthe steel sheet is perforated ( 30% open

area) and the acousticmaterial is covered with a fiberglasscloth

and a wire mesh. The panels are attachedto the inner flangesof

the wall columns and trusses trough the corrugatedsteel sheets by

means of channels, battens and couplings. The panels on the floor

are connectedtogetherwith battens and are bolted to the concrete

of the floor in several places.

In order to avoid excessive turbulence, tapered fairings are

provided at both the upstream and downstreamend of the settling

chamber to cover the steps between the inner surfaces of the

panels and the surfaces of neighboring elements of the wind

tunnel.

A brief review of the existing structureof the settling chamber

- has indicatedthat no large-scalestrengtheningwill be required

to support the new acoustic treatment particularly at the roof

level; however, minor local reinforcements may be necessary.

These reinforcementswill be configuredin the design phase.

The bulk absorber concept recommendedin Reference 1 should also

be reviewed duringthe design. As an alternative,a 0.6 m (2-ft)
Page 24

deep treatmentwith approximately0.15 m (6-inch)thick panels at

the airflow side and 0.45 m (18-inch)airspace between the panels

and the corrugated sheet shell, should be carefully evaluated.

Such a treatment may provide acceptablenoise reductionat lower

cost than the bulk absorber.

2.3 Test Chamber AcousticTreatment

2.3.1 Treatment Concept

lhe test chamber acoustic treatment is based on the recommendations of Reference2 (Attachment2) and Reference3.

Two types of treatmentare used:

- 0.6 m (2 ft) deep flat panels installedon the floor within

the air flow area and to the left of it looking downstream,

and also on the adjacent (left-hand)wall of the test chamber

parallelwith the airstream.

- 0.9 m (3 ft) deep panels with wedges installed on the

remainderof the floor, the remainingwalls, the undersideof

the roof trusses and the undersideof the movable ceiling.

As the wind tunnel is to be convertible between acoustic and

aerodynamic operation, the treatment on the floor and on the

undersideof the movableceiling is removable.

The general arrangementof the acoustic treatment is shown on

Drawing LD - 544306, Sheet 1 and 2.

Design of the flat panels consists of a galvanized sheet metal

enclosure covered on the airflow side by perforated steel sheet

with 30% open area. The enclosureis filledwith mineral wool or

fiberglas with a density of 4 Ib/ft3; to prevent release of the
Page 25

fill material into the airstream, a covering of fiberglascloth

and fine wire mesh is used below the perforated cover sheet.

Construction of these removablefloor panels is sturdy to allow

. (possiblyfrequent)handling,and has provisionsfor lifting with

a fork-lifttruck.

Tapered fairings are installedon the floor at the inlet and the

outlet of the test section to smooth-outthe 2 ft steps between

the surfaceof the flat panels and the originalwind tunnel floor.

The fairings are made in sections (eighteach at the upstreamand

downstreamend) and are built of aluminum,to ease handling. Each

section consists of an upper plate and a set of longitudinaland

transversestiffenersthat are welded to the plate. Rubber seals

are provided around the perimeterof each section. Before they

are finally fastened to the wind tunnel floor, the individual

sections must be properly aligned. To facilitate this task,

omnidirectionalcasters are installed on the underside of each

section.

Construction of the panels with wedges is similar to that of the

flat panels. The wedges are attached to a sheet metal base and

are made of mineral wool or fiberglas, covered with fiberglas

cloth and wire mesh (22 GA wire, 0.5" x 1" spacing). The wedges

are placed within the panels in perpendiculargroups of 3 or 4,

(to improve the acousticperformance). The removablepanels again

have sturdier design compared to the permanentinstallation,and

have lifting provisionssimilar to the flat panels.

The permanent acoustic treatment panels are attachedto the test

- chamber structure using channels, battens and bolts as indicated

in detail Z of Drawing LD - 544306, Sheet 1. The panels attached

@

to the walls are largely self-supportingsince the lower panels

support the weight of the upper panels; loads transferredto the

test chamber structure are not large and can be accommodated

without major structuralmodifications.
Page 26

A preliminary estimate of the allowableextra loads on the test

chamber roof structurehas been done by NASA. It appears that no

major modificationsof the roof will be required when the wedge

panels are installed (thewedge panelswill impose a load of about

12 psf as compared to the estimated allowableextra load of 20

psf). However, detail analyses of the roof structure will be

4

required,to define all the necessarylocal reinforcements.

The removablefloor panels will be bolted to the eXisting floor;

here, considerationwill be given to interlockingthe panels so

that the number of fasteners penetratinginto the floor Can be

minimized (as the floor openings must be plugged when converting

to the aerodynamictesting mode).

Design of the removableacoustic treatment panels must take into

account the requirement for a quick conversion, that is,

installation or removal of the panels. A design concept to

accomplishthis task has been developed and is discussed in the

followingsection.

2.3.2 Installationand Removal

The installation or removal of the acoustic panels will be a

fairly complex task because the area to be covered is large and

rather irregular; also the panels, especially the wedges, Will

have to be handledcarefullyso as not to damage them,

Therefore, the task will have to be well Organized to even

approachthe conversiontime of two shifts desired by NASA.

B

The installationconcept takes into account the susceptibilityof

the panels to damage, and the fact they will be stored Outside the

test chamber.
Page 27

The panels are stored in special storage racks and each rack is

lifted into the test chamber through the open floor area (see

Drawing LD 544306, Sheet 1) by the existingoverhead crane.

For the installationof the wedge panelson the undersideof the

" movable ceiling, a special portable hoist will be permanently

located on the top of the ceiling. The panels are individually

lifted from the storage racks using this hoist. When a panel has

been fastened to the ceiling, the hoist is disconnectedand moved

to an adjacentlocationfor installationof another panel.

The floor panels are withdrawn from the racks one by one and

placed in their proper location, using a fork-lift truck. Each

panel is identified and has its assigned location which must not

change. Adherenceto this simple rule in conjunctionwith a fixed

sequence of installationwill improve the installationtime.

Once the regular panels have been installed,the fork lift truck

is removedfrom the test chamber. Then small panels (someof them

irregular) are brought in and placed by hand in the area of the

collectorand close to the floor opening.

It should be noted that the fork lift truck is brought in and

removed from the test chamber using the existingoverhead crane.

Initial enquiries to the manufacturersof fork-lifts have shown

that the smallesttrucks weigh in excessof 10,000 Ibs and this is

well over the capacity of the crane. For the purpose of this

study it has been assumed that the crane capacity will be

increased; however, further investigationsshould be made to see

if lighter fork liftscan be supplied.

The storage of the acoustic panels and floor fairings outside the

test chamber will require construction of a storage building,

since there is no storage room anywhere within the existing

building.
Page 28

In addition, it will be necessary to provide an area for

preparationand checkoutof the acousticmodels.

Therefore, it is proposedto build a new small buildingfor these

two purposes. The buildingsize has been estimatedat 15 x 17 m

(50 x 55 ft) and 5.5 m (18 ft) high, and its locationis shown on

Drawing LD - 544301. A large door in this buildingis located in

line with the access door into the "basement"of the test chamber.

The buildingconstructionis prefabricatedsteel, of the type supplied by Butler Manufacturingand other companies. The building

is insulated and heated. The area allocated for the model

preparationand checkout is approximately7 x 6 m (23 x 20 ft).

Transportation of the storage racks with acoustic panels between

this building and the test chamber basement is acomplishedby a

second fork-lifttruck.

This procedure will obviously require further refinements and

detail consideration. However, it is simple in concept, and

feasible.

2,4 Turnin 9 Vanes AcousticTreatment

2.4.1 AeroacousticConsiderations

In Reference 3, the recommendedconcept for the acoustic turning

vanes in corners i and 2 was profiled vanes with a chord and

thickness of approximately 5.0 and 0.5 m respectively; the

interior consistingof variable geometry (or depth) cavities with

acoustic absorptive material, and covered with perforated sheet

metal facing on both airflow surfaces. Reasonable acoustic

performance was claimed for these vanes; however, they would be

expensive to manufacture and install, and they would interfere

with the flow control "chokeflaps" downstreamof corner 1 due to
Page 29

their long chord. As an alternative,DSMA investigatedthe use of

a simpler vane consistingof rolled plate with acousticmaterial

mounted on only one side (pressuresurface). Vanes of this type

. are used in the DNW tunnel in The Netherlands,Reference4.

• From the aerodynamicpoint of view, the optimum chord length for

turning vanes in corners 1 and 2 would be 1.6 m (5.2 ft) based on

normal DSMA design procedure. The acoustic performanceof these

vanes was estimatedfrom data supplied by DNW, and compared with

the predictedperformancefor the vanes recommendedin Reference

3. At frequenciesof 500 Hz and above, both types of vanes had

equivalent performance; but in the 125 and 250 Hz bands, the

rolled plate vanes gave significantlyless attenuationthan the

profileddesignof Reference3.

The low frequency attenuationof the rolled plate vanes can be

increased by increasing the chord length of the vanes. The

performance improvementwas estimatedfor chord lengths of 2.5 m

(8.2 ft) and 4 m (13.1 ft), and is compared with the 1.6 m vane

and the profiled vane performancepredictions,in Table 7.1t can

be seen that rolled plate vanes with chord lengthsof 1.6 and 2.5

m do not achieve as much attenuationat the low frequencies(125

and 250 Hz bands) as the profiledvanes, but a roller plate vane

with a chord lengthof 4.0 m gives equivalentacousticperformance

over the whole frequencyrange.

Based on these results, it was concludedthat rolled-platevanes

with a chord lengthof 4.0 m (13.1 ft) could be used in corners 1

and 2 to achieve the required attenuation;and the cost of these

- vanes would be lower than that for the profiledvanes recommended

in Reference3.

2.4.2 StructuralConcept

A layout of corner 1 with the new 4 m chord, rolled plate turning

vanes, is shown on the Drawing LD - 544307. There are 8 complete
Page 30

vanes and an incompletevane in the outer corner. Overall, the

interferencewith the flow control vane assemblydownstreamof the

corner is minimal. The spacing of the turning vanes may be

slightly altered in the design phase to place the second vane

(from the inner corner) in line with the flow control vane. This

will remove the small misalignment seen on the drawing, and

improve the flow through the corner. The turning vanes in corner

2 will be identical.

The design concept for a typical turning vane including the

acoustictreatmentis also shown on the drawing. A standardsteel

plate vane is the principal structuralmember. On its pressure

side, fairings and continuousflanges are attached at the leading

and trailing edges. Flanges are also located at the center chord.

Modular acoustictreatmentpanels are boltedto the flanges.

The panel design consists of a perforated sheet at the airflow

side, supported by an "eggcrate"grid of stiffeners. Each grid

spacing is filled with acoustic absorptionmaterial,mineral wool

or fiberglas, sewn into a cover mat of fiberglas cloth. The

panels are self-supporting, and will be delivered to site

completely assembled. Their installationonto the steel plate

vanes will be straightforwardand, compared to modificationsin

other areas of the wind tunnel, relativelyshort.

2.5 Relocationof Control Room

The control room is at present built inside the test chamber.

When the test chamber is transformedinto a semi-anechoicchamber

during the modificationscovered by this study, the control room

obviouslymust be relocated.

DSMA discussed with Langley personnel the possible options for

location of the new control room, and finally selected the
Page 31

location adjacent to the present control room, outside the test

chamber walls.

. A layout was developedand is shown on drawing LD - 544305. The

size of the new control room was initiallyspecifiedas 12 x 4.5 m

- (40 x 15 ft); however,during discussionsat NASA Langley prior to

the Design Review Meeting on 7 November,1984, it was agreedthat

the size was rather marginal. It was decided to increase the

width to 7.6 m (25 ft) so that sufficientflexibilityfor further

upgrades is built in.

The new control room layout features simple access into the test

section - a door with an airlock is situated next to the

contraction outlet. When the wind tunnel is configured in the

acoustictesting mode, personnelrequiringaccessto the model can

step out almost directlyonto the flat acoustic panels located in

the flow area.

A second means of accessor egress is provided directly into the

wind tunnel buildingoutside the test chamber.

The control room has a large window area for model observation,

and the control consolescan be placed in front of the windows as

schematicallyshown on the drawing. In any case, the windows will

be covered with acoustictreatment during acoustictesting.

The construction of this control room is a conventional steel

structure with steel cladding. No design problems are expected

here and no detailconsiderationwas given to the design in this

• conceptualphase.

The major design issue associatedwith the control room relocation

will be the re-routing of all the existing power, control and

instrumentationlines from the present to the new location. The

concept proposedby DSMA is as follows:
Page 32

- Most of the cables enter into the presentcontrol room at the

north-eastcorner of the test chamber. The new control room

is placed adjacent to and directly across the test chamber

east wall.

- An electrical terminationcabinet will be placed inside the

new control room, very close to this existing cable entry

point.

- In general, the constructionof the new control room can be

almostcompletedbefore the wind tunnel shut-downso that the

termination cabinet can be ready at the point of the

shut-down.

- When the wind tunnel has been shut down for the modifications, all the cables will be disconnected and tagged,

enabling the removal of the control consoles, and demolition

of the structureof the presentcontrol room.

- All the cables will be brought into the electricaltermination cabinet and fastenedto the allocatedterminal strips.

- During the installationand wiring of the control consoles in

the new control room, new cables will be installed (within

the computer floor provided)between the terminationcabinet

and the consoles.

This procedure will ensure orderly re-wiring and a minimum of

interfaceproblems.

2.6 Stin 9 and Rotor Drive

Conceptual design of this model support equipment has been

includedin the scope of work for the followingreasons:
Page 33

- The present cranked sting support was designed for

aeronautical testing and it is larger and longer than

desirable for rotorcraft aeroacoustictesting. The design

• requirementsfor the new sting were defined specificallyfor

the aeroacoustictesting•

-The existing rotor drive can be operated only in an upright

positionwhile the aeroacoustictest requirementsnecessitate

rolling the rotor +/-1800. Also, the rotor drive power on

the new drive should be increasedfrom 35 to 60 HP.

DSMA had several discussionswith the users of the system and the

designers of the existingrotor drive. As a result,the concepts

describedin the followingsections were developed.

2.6.1 Stin9 Support System

A brief evaluationwas carried out to determinethe suitabilityof

a "cranked rotary sting" versus a double-articulatedtype such as

is used at DNW.

The cranked rotary sting utilizes relatively simple rotary

actuators to achieve the various combinationsof roll, pitch and

yaw and is hence simpler to maintain and less expensive to

construct. Furthermore, due to the nature of its design, the

pivot point is fixed in space• The articulated sting type,

however,will always have some relativemotion of the pivot point

althoughthis is usually minimal. Actuationis achievedby linear

hydraulic or electro-mechanicalactuators which can be costly.

• Furthermore,the articulatedsting designedto the same stiffness

and freedom from backlash as the cranked rotary type will likely

present more blockageto the airflow. For these reasons and given

the fact that a cranked sting is already in use in the 4 x 7 m

tunnel, a version of the cranked sting design was selected for

study.
Page 34

Drawing No. LD - 544308,Sheet 1, illustratesthe general arrangement of the rotor drive and the cranked rotary sting. The sting

has been designed to provide +/-3600 roll and +/-200 pitch and

yaw. An internal passage providesfor supply of 30 Ibs/secof air

at 5000 psi in additionto oil and water supply and return lines

and electricalconductors. The length of each rotary joint has

been minimized to allow the sting to be compactedto a relatively

clean configuration immediatelybehind the model. This can be

achieved with an overall distanceof 3.7 m (12.25ft) betweenthe

model pivot point and the support mast centerline. The inset in

the bottom left hand corner of the drawing illustrates the

possible use of a "jogged"mast extensionwhich shifts the rotary

actuatorsfurther downstreamfrom the model should it be necessary

to accommodate a larger model or have a cleaner configuration

behind the model. This would however, limit the amount of

vertical translation which could be generated from the model

supportcart.

Sheet 2 of Drawing LD - 544308 illustratesa cross-sectionalview

of rotary joint No. 1. Control and instrumentationcables are

routed through the center of the rotaryjoint while the air, oil,

and water supply and drain lines are connected via drillingsto

annular spaces in the non-rotatingportion of the joint. These

annular spaces are separated by seals and vent spaces as

appropriate. The air passage (5000 psi) is sealed by glass

reinforced U cups. Rotary motion is achievedby a DC gear motor

with an integralbrake and a multi-stageplanetarygear head which

is arranged below a harmonic drive that it drives through an

intermediatespur gear.

i

Rotary joint No. 1 incorporatesa removablemodel support section

which forms the connecting link between the model and the joint.

Provision for removal is necessary in order to fit longer or

shorter stings or stings with angles built-in or with different

balance support structures. Attachment to the rotary joint is

achieved through a keyed taper held in place by a locking ring.
Page 35

Prior to the design reviewmeeting held at Langley on November 7,

1984, this tapered connection was located within the body of the

rotaryjoint and carried the oil and water services and electrical

• conductors as well as the air supply. These services could then

be carried within the sting right up to the balance attachment

- point. This resultedin a rotaryjoint that was fairly bulky and

which presentedmore blockageto the air flow than was desirable.

Accordingly, the design was revised to the arrangementpresently

shown.

Model positioncontrol would be achievedvia a positioncontroller

designedto:

- transform roll, pitch and yaw commands into the appropriate

angularorientationsfor the three rotaryjoints,

-host communications (master/slave)from an external test

automationsystem and providecommand/statusinterfacing,

- provide a local command interfaceas well as a local position

display,

- provide output signals of current position for use by the

test automationsystem or elsewhere,

-input appropriate control constants as required for any

modificationsof the sting geometry.

The sting support control system will be configured to be

. compatiblewith the existingfacilitycontrol system.

" 2.6.2 Rotor Drive System

The general concept for the rotor drive shown in Drawing

LD - 544309, Sheet 1, is based on the U.S. Army 2 m Rotor Test

System with modificationsmade to permit operationwith the roll,
Page 36

pitch and yaw inputs indicatedabove. The majorityof the design

work carried out as part of this study centered on the gear box

and particularlyon its lubricationsystem which will be described

in more detail below. The rotor is driven by an Able Corporation

75 HP, water cooled electricmotor (designrequirementscalled for

a 60 HP motor while the closest Able design is capable of 75 HP).

The rotor head is a four-bladed design with adjustable viscous

dampers on the lead/lagpivot point and potentiometersto resolve

the flap and lead/lag angles. Cyclic and collective inputs are

fed to the blades through the rotating and non-rotating swash

plates from three electro-mechanicalactuatorsmounted on top of

the gear box. Flap and droop stops are providedso that the model

can be stopped in any attitude.

The entire drive system is supportedon a gimbal mount where any

vibration is reacted by springs and adjustableviscous dampers.

The springs and dampers will be selected to locate the resonant

frequenciesof the rotor drive system outside the normal operating

speed range.

Separate balancesare providedfor the fuselage and rotor drive as

well as a total balancewhich connects to the sting.

Further detail of the gear box design is shown on Sheet 2 of

Drawing LD - 544309. A pair of spiral bevel gears carry the drive

input from the motor to the intermediate shaft and achieve a

reduction ratio of 2:1. Final reductionis achievedby a pair of

helical gears also with a ratio of 2:1 (or greater if required).

Final selection of tooth geometry will be based on available

manufacturingequipmentin order to minimizecosts.

Lubrication and cooling of the gears and all the bearings is

achieved by individualspray feeds. Two nozzles spray oil on the

mesh points of the two gear pairs. An additional two nozzles

spray the intermediategear shaft bearings from the side of the

bearing cap. This allows the oil to be carried through by the
Page 37

pumping action of the bearing. Similarly,oil is spray-fed from

between the pair of tapered roller bearingson the output shaft.

The pumping action of the bearingscarries the oil either through

the drain holes providedor onto the helical gear from which it is

" flung to the side of the gear box. Oil fed to the cylindrical

roller bearing of the output shaft will drain by gravity through

the drain holes or, with the gear box inverted,will fall back

down onto the gear.

Feeding the oil to the gears and bearings is relativelysimple

compared with the scavenging system requiredto insure that the

•box does not fill up. A brief reviewof accessorygear boxes on

aircraft engines which may be called upon to operate in an

inverted attitudeshows that

- either two scavenge pump pick-up points are used with

selection made by gravity acting on a suitable switchover

device,

- or the scavenge points are located at the bottom of the gear

box only for operationin a normal attitudeand when inverted

or in unusual attitudes,the gear box is allowed to fill with

oil.

The second case is considered acceptable for an aircraft

application. Oxidation of the oil caused by aeration when in

contact with the gearing is minimal due to the short time spent in

the unusual attitude,and the power lost by the action of churning

the oil is insignificantwhen compared with the amount of power

availablefrom the engine. In the case of the subject rotor drive

o

system, degradation of the oil could be tolerated to a certain

extent as a relatively large reservoir is available externally,

but a large power loss could not be tolerated as only limited

power is availablewithin the constraintsof the model envelope.
Page 38

The number of oil scavenge points is largely dependent upon the

size of the gear box casing - a large casing can incorporate

considerable sump capacity which will a11ow the oil to collect

regardlessof model attitudeand can be scavengedbeforethe level

reaches the gears. A compromise between gearbox size and

excessivedrain connectionsresultedin the incorporationof eight

scavengepoints, one at each corner of the box. A rotaryselector

valve is used to connect the drain line with the appropriate

scavenge point. The rotaryselector is driven by a stepper motor

connected through a gear set. Gravity and an eccentricweight on

the rotary valve could have been used to achieve the appropriate

selection; however, it was felt that more positive results would

be obtained by a motor drive with input from the sting control

system. This also results in a more compact arrangement.

The selectionof a pressurizedgear box versus one operated with

some degree of vacuum is based mainly on considerationsof the

effects of leakage. With this in mind and given the availability

of an existing vacuum oil lubricationsystem, vacuum scavenging

was adopted. The degree of vacuum in the gear box is determined

by the pressure loss at the vent fitting. This loss is minimized

to insure that sufficient pressure is still availableto push the

oil through the drain line and sting back to the vacuum reservoir.

Within the gear box, a small trap is providedon the air vent line

to prevent any oil loss when the model is stopped in an inverted

attitude.
Page 39

3. COST ESTIMATES

3.1 General

" The budgetarycost estimates presentedin this section have been

based on the designs developedin the study, shown on the layout

drawings and describedin the report.

The estimates include material, shop fabrication, assembly,

erectionand the requiredcheckouttesting. Costs of engineering,

procurement and construction management are not included. No

allowance has been made for taxes or custom duties. An optimum

fabricationand erectionschedule was assumed;thus, no allowance

was made either for compressingor stretchingthe program.

The estimates have been based on costs developed in-house from

weight estimatesand cost data from other similar projects,and on

cost estimatesobtained from suppliersof the proprietaryitems.

In particular,the fan nacelle and fan rotor costs were estimated

on the basis of weight estimates and unit costs from similar

recent DSMA projects.

The cost estimate for the fan blades was based on budgetarycost

estimates receivedfrom two potentialsuppliers, Hoffmann Co. in

Germany and Permali Co., in England.

The acoustic treatment in the settling chamber and in the test

chamber was costed in-house, and confirmatory estimates were

obtained from Eckel Industries,a supplier of anechoic chambers

and acoustic treatment panels. Transport and installation

equipment costs (for the removablepanel handling)were obtained

from equipmentsuppliers.
Page40

The constructioncosts for the new control room were preparedfor

DSMA by a civil engineeringcompany while the costs for re-routing

the electrical cabling were estimated by the DSMA electrical

department.

( The acoustic model preparation building costs were based on a

budgetary estimate from Butler Manufacturing, a supplier of

prefabricatedbuildings.

DSMA designed the acousticallytreated corner vanes on DNW wind

tunnels and, more recently,on a low speed wind tunnel (of similar

size to the 4 x 7 m) presentlyunder constructionin Europe. The

cost data from these two projectswas used to estimatethe cost of

the new acousticallytreated vanes in corners 1 and 2.

The sting and rotor drive system costs were based on discussions

with personnel of NASA Langley, and Sikorsky Aircraft (for the

rotor drive system). It should be noted that the costs of the

control system hardware and software for these two systems are

excluded.
Page 41

3.2 Cost Estimate (1984 Dollars)

US DolIars

(000)

Fan ........................... 3,300

- New Fan Centerbody(Nosecone,nacelle, 1,000

tailcone)

Fan Drive - Modified (coaxialgearbox) 400

Fan Rotor 400

Fan blades 1,500

SettlingChamber AcousticTreatment ........... 1,100

Relocationof Control Room ............... 250

Test Chamber ....................... 1,050

AcousticTreatment 900

Transport and InstallationEquipment 150

AcousticModel PreparationBuilding............ 100

Corner Vanes ....................... 550

Removal of existingvanes 50

New vanes with acousticpanels 500

Sting and Rotor Drive System ............... 1,200

- Sting Support 450

Rotor Drive 750

TOTAL ....... 7,550
Page 42

4. PRO_CT SCHEDULE

The project schedule is shown in Figure 4. It covers only the

constructionphase of the project;the engineeringand procurement

(tenderingand contract award) activitiesare excluded.

An optimum schedule has been assumed as already mentioned in the

previous section. Duration of the individual activities were

discussedboth internallywithin DSMA and with potentialsuppliers

(fan blades, acoustic treatment). The total duration of the

constructionphase up to the point of the aeroacousticperformance

verification (commissioning) is 16 months, and the estimated

shutdown of the facility is 6 months. It is felt that the fan

modificationscan be done faster than shown, especially when the

proposedconcept with coaxial gearbox is adopted. However, it is

not likely that the facility shutdown can be reduced below 5

months.

The sting support and rotor drive are shown as requiring16 months

to completion. However, this activity is not necessarily

connected with the facility shut down; furthermore, it could be

initiatedearlierthan the remainderof the work.
Page 43

5. CONCLUSIONS

As a resultof this study, the followinghas been concluded:

- Mechanical feasibilityhas been establishedfor implementation of BBN "Scheme B" for the modificationof the 4 x 7 m

i.

tunnel for aeroacousticresearch.

- The design goal for 50 percent reductionin fan speed has not

been achieved and is not feasible with a conventional fan

design.

- The test section noise level specification may well be

achievable with the fan design proposed in the study.

However, the substantiationof the acoustic performanceof

the fan assemblywas not within the scope of this study and

will be assessedby NASA.

- The closed test section performanceof the facility with the

new fan will be improvedover the present configurationdue

to the improvementin fan efficiency.

- The proposed modifications can be accomplished within a

reasonabletime and at a reasonablecost.
Page44

REFERENCES

(1) Hayden, R. E., and Wilby, J. F., "Sources, Paths, and

Concepts for Reduction of Noise in the Test Section of the

NASALangley 4 x 7 m Wind Tunnel", NASACR-172446-I,

September,1984.

(2) NASARequest for Proposal 1-14-5627,0236 Architect-Engineer

Services for Feasibility Study for Modifications to the 4 x 7

Meter Tunnel for Aeroacoustic Research, Bulding 1212C. July

24, 1984.

(3) Hayden, R. E., "Addendum and Executive Summary: Sources,

Paths, and Concepts for Reduction of Noise in the Test

Section of the NASALangley 4 x 7 m Wind Tunnel", NASA

CR-172446-2, September, 1984.

(4) van Ditshuizen,J. C. A., and Ross, R., "Aerodynamicand

AeroacousticDesign Aspects" in "Construction1976-1980",

M. Seidel, Editor, D.N.W., May 1982.

(5) Applin, Z. T., "Flow Improvementsin the Circuitof the

Langley 4- by 7- Meter Tunnel", NASATM-85662, December 1983.
I. TABLES}

4&
LANGLEY 4 X 7 M. TUNNEL - EXISTINg, CLOSED T/S, 0CT. 30/84.

TEST SECTION CONDITIONS

MACH NUMBER - 0.2850

TOTAL PRESSURE - 1.0721 BARS

TOTAL TEMPERATURE - 293.7000 DEg. K.

DYNAMIC PRESSURE - 0.0576 BARS

CHORD REYNOLDS NUMBER - 3.5796 MILLIONS

FAN LOSS FACTOR(DPTF/GTS) - 0.2493

TOTAL PRESSURE RISE - 0.0144 DARS

AIR POWER - 5898.3991KW

EFFICIENCY - 0.6700

(PTFO/PTFI) - 1.0135

(RMF*SGRT(TRFI)/PRFI) - 3346,2277

CIRCUIT TRANSIT TIME - 12.0265 SEC.

EGUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAOE - 0.0000

TUNNEL MASS FLOW - 3478.4118 KgR./SEC.

FAN INLET UNIT RE. - 1,7007 MILLIONS/M.

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER DLOCRAGE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SQ.M. BARS DEg. R. M./SEC. LOCAL T/S

TEST SECTION 29.305 0.2850 1.0721 1.0133 293,700 289.005 97,061 0.0000 0.0000

T/S DIFFUSER 29,614 0.2817 1.0721 1.0146 293.700 289.113 95.942 0.0775 0.0758

CORNER 1 79,008 0.1018 1.0677 1.0600 293,700 293,093 34.898 0.1500 0.0200

CROSSLEg 1 79.008 0.1019 1.0666 1.0589 293.700 293.092 34.936 0,0775 0.0103

CORNER 2 86.304 0.0932 1.0660 1.0595 293.700 293.191 31.973 0.1500 0,0168

FAN INLET S6.304 0.0933 1.0650 1.0586 293.700 293,190 32.002 0.1975 0.0221

FAN 112.615 0.0714 1.0637 1.0600 293.700 293.401 24.511 -3.8046 -0.2500

FAN TAILCONE 112.615 0.0706 1;0781 1.0744 294.831 "294,537 24.276 0.0473 0.0031

FAN DIFFUSER 141.448 0.0562 1.0780 1.0756 294.831 294,645 19,314 0.2024 0.0083

AIR OUTLET 263.329 0.0301 1.0775 1.0768 294.831 294,777 10,367 0.0000 0.0000

CORNER 3 263.329 0.0301 1.0775 1.0768 293.700 293.647 10.328 0.1500 0.0018

CROSSLEg 2 263.329 0.0301 1.0774 1.0767 293,700 293,647 10,328 0.0008 0.0000

CORNER 4 263.329 0.0301 1.0774 1.0767 293.700 293.647 10,328 0.1500 0.0018

SETTLINg CHAMBER 263.329 0.0301 1.0773 1.0766 293.700 293.647 10.328 4.0031 0.0474

CONTRACTION 263.329 0.0302 1.0746 1.0739 293.700 293.647 10.355 0.0092 0.0001

TEST SECTION 29.305 0.2842 1.0745 1.0159 293.700 289.030 96.800 0,0412 0.0411

Table 1. Losses, Existing Circuit, Power Point

a) Closed Test Section
! • f

LANGLEY 4 X 7 M. TUNNEL - EXISTINg, OPEN T/S, 0CT. 30/84.

TEST SECTION CONDITIONS

HACH NUMBER - 0.2170

TOTAL PRESSURE - 1.0471 BARS

TOTAL TEMPERATURE - 291.7000 DEQ. K.

DYNAMIC PRESSURE - 0.0334 BARS

CHORD REYNOLDS NUMBER - 2.7259 MILLIONS

FAN LOSS FACTOR(DPTF/QTS) - 0.7192

TOTAL PRESSURE RISE - 0.0240 BARS

AIR POWER - 5859.7333 KW

EFFICIENCY - 0.8700

(PTFO/PTFI) - 1.0232

(RMF*SGRT(TRFI)/PRFI) - 2&07.5574

CIRCUIT TRANSIT TIME - 15.6274 SEC.

EGUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAGE - 0.0000

TUNNEL MASS FLOW - 2648.5909 KgR./SEC.

FAN INLET UNIT RE. - 1.3015 MILLIONS/M.

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER BLOCKACE - 8,1B03 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SQ.M. BARS DEQ. K. M./SEC. LOCAL T/S

TEST SECTION 29.305 0.2170 1.0471 1.0133 291.700 288.978 73.899 0.000 0.0000

COLLECTOR 32.620 0.1938 1.0471 1.0200 291.700 289.525 &&.067 0.329 0.2641

CORNER I 79.008 0.0792 1.0383 1.0337 291.700 291.334 27.082 0.150 0.0204

CROSSLEg 1 79.008 0.0793 1.0376 1.0330 291.700 291.334 27.100 0.077 0.0105

CORNER 2 86.304 0.0725 1.0372 1.0334 291.700 291.393 24.806 0.150 0.0171

FAN INLET 86.304 0.0726 1.0367 1.0329 291.700 291.393 24.820 0. 197 0.0225

FAN 112.615 0.0556 1.0359 1.0337 291.700 291.520 19.016 -10.734 -0.7188

FAN TAILCONE 112.615 0.0545 1.0599 1.0577 293.616 293.441 18.708 0.048 0.0032

FAN DIFFUSER 141.448 0.0434 1.0598 1.0584 293.616 293.505 14.888 0.203 0.0085

AIR OUTLET 263.329 0.0233 1.0595 1.0591 293.616 293.584 7.994 0.000 0.0000

CORNER 3 263.329 0.0232 1.0595 1.0591 291.700 291.669 7.943 0.150 0.0018

CROSSLEG 2 263.329 0.0232 1.0595 1.0591 291.700 291.669 7.943 0.001 0.0000

CORNER 4 263.329 0.0232 1.0595 1.0591 291.700 291.669 7.943 0.150 0.0018

SETTLINg CHAMBER 263.329 0.0232 1.0594 1.0590 291.700 291.669 7.943 4.003 0.0479

CONTRACTION 263.329 0.0233 1.0578 1.0574 291.700 291.668 7.955 0.010 0.0001

TEST SECTION 29.305 0.2147 1.0578 1.0244 291.700 289.035 73.127 0.325 0.3217

Table 1. Losses, Existing Circuit, Power Point

b) Open Test Section
d8

Assumed Conditions

PSQo= 2116 PSF

TSQO= 60°F

PM -- 8,000 HP

2xl.0Q Screens in Settling Chamber

Quantity Test Section

Closed Open

Mach Number 0.285 0.217

Dynamic Pressure (PSF) 120 70

Fan Speed (RPM) 275 220

Loss Factor 0.25 0.72

Fan Efficiency (%) 0.67 0.87

Table 2. Loss Summary, Existing Circuit
LANGLEY 4X7 TUNNEL - FAN DESIGN CASE, CLOSED T/S, 120 PSF, 0CT. 30/84.

TEST SECTION CONDITIONS

MACH NUMBER - 0.2850

TOTAL PRESSURE - 1.0721 BARS

TOTAL TEMPERATURE - 293.7000 DEg. R.

DYNAMIC PRESSURE - 0.0576 BARS

CHORD REYNOLDS NUMBER - 3.5796 MILLIONS

FAN LOSS FACTOR(DPTF/GTS) - 0.2659

TOTAL PRESSURE RISE - 0.0153 BARS

AIR POWER - 5114.4664 KW

EFFICIENCY - 0.8200

(PTFO/PTFI) - 1.0144

(RMF*SGRT(TRFI)/PRFI) - 3343.1790

CIRCUIT TRANSIT TIME - 11.4852 SEC.

EGUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAGE - 0.0000

TUNNEL MASS FLOW - 3478.4118 KgR./SEC.

FAN INLET UNIT RE. - 2.2069 MILLIONS/M.

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER BLOCKAGE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SG.M. BARS DEg. K. M./SEC. LOCAL T/S

TEST SECTION 29.305 0.2850 1.0721 1.0133 293.700 289.005 97.061 0.0000 0.0000

T/S DIFFUSER 29.614 0.2817 1.0721 1.0146 293.700 289.113 95.942 0.0775 0.0758

CORNER 1 79.008 0.1018 1.0677 1.0600 293.700 293.093 34.898 0.1700 0.0227

CROSSLEg 1 79.008 0.1019 1.0654 1.0587 293.700 293.092 34.941 0.0775 0.0103

CORNER 2 86.304 0.0932 1.0658 1.0594 293.700 293.190 31.978 0.1700 0.0190

FAN INLET 86.304 0.0933 1.0647 1.0583 293.700 293.189 32.011 0.0058 0.0007

FAN 86.833 0.0928 1.0647 1.0583 293.700 293.196 31.816 -2.4013 -0.2656

FAN TAILCONE 86.833 0.0916 1.0800 1.0737 294.900 294.406 31.489 0.0817 0.0089

FAN DIFFUSER 141.448 0.0561 1.0795 1 0771 294.900 294.715 19.290 0.2024 0.0083

AIR OUTLET 263.329 0.0301 1.0790 1 0783 294.900 294.847 10.354 0.0000 0.0000

CORNER 3 231.799 0.0341 1.0790 1 0781 293.700 293.632 11.716 0.1500 0.0023

CROSSLEg 2 231.799 0.0341 1.0789 I 0780 293.700 293.632 11.718 0.0058 0.0001

CORNER 4 231.799 0.0341 1.0789 1 0780 293.700 293.632 11.718 0.1500 0.0023

SETTLINg CHAMBER 263.329 0.0300 1.0787 1 0781 293.700 293.647 10.314 6.3031 0.0745

CONTRACTION 263.329 0.0302 1.0744 1 0738 293.700 293.647 10.355 0.0092 0.0001

TEST SECTION 29.305 0.2842 1.0744 I 0158 293.700 289.030 96.800 0.0412 0.0411

Table 3. Losses, Proposed Circuit

a) Closed Test Section, Power Point
LANGLEY 4X7 TUNNEL - FAN DESIGN CASE, OPEN T/S, 70 PSF, 0CT. 30/84

TEST SECTION CONDITIONS

MACH NUMBER - 0.2170

TOTAL PRESSURE - 1.0471 BARS

TOTAL TEMPERATURE - 291.7000 DEg. K.

DYNAMIC PRESSURE - 0.0334 BARS

CHORD REYNOLDS NUMBER - 2.5310 MILLIONS

FAN LOSS FACTOR(DPTF/GTS) - 0.7126

TOTAL PRESSURE RISE - 0.0238 BARS

AIR PONER - 5444.2288 KW

EFFICIENCY - 0.8000

(PTFO/PTFI) - 1.0230

(RMF_SGRT(TRFI)/PRFI) - 2247.1059

CIRCUIT TRANSIT TIME - 17.1963 SEC.

EGUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAGE - 0.0000

TUNNEL MASS FLOW - 2283.3927 KgR./SEC.

FAN INLET UNIT RE. - 1.4556 MILLIONS/M.

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER BLOCKAGE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SQ.M. BARS DEg. K. M./SEC. LOCAL T/S

TEST SECTION 25.260 0.2170 1.0471 1.0133 291.700 288.978 73.899 0.0000 0.0000

COLLECTOR 28.118 0.1939 1.0471 1.0200 291.700 289.524 66.081 0.3462 0.2781

CORNER 1 79.008 0.0683 1.0378 1.0344 291.700 291.428 23.343 0.1700 0.0172

CROSSLEQ I 79.008 0.0683 1.0372 1.0339 291.700 291.428 23.358 0.0773 0.0078

CORNER 2 86.304 0.0625 1.0370 1.0341 291.700 291.472 21.381 0.1700 0.0144

FAN INLET 86.304 0.0625 1.0365 1.0337 291.700 291.472 21.392 0.0058 0.0005

FAN 86.833 0.0622 1.0365 1.0337 291.700 291.475 21.261 -8.5107 -0.7125

FAN TAILCONE 86.833 0.0610 1.0603 1.0575 293.598 293.380 20.920 0.0848 0.0070

FAN DIFFUSER 141.448 0.0374 1.0600 1.0590 293.598 293.516 12.830 0.2036 0.0063

AIR OUTLET 263.329 0.0201 1.0598 1.0595 293.598 293.574 6.890 0.0000 0.0000

CORNER 3 231.799 0.0227 1.0598 1.0594 291.700 291.670 7.778 0.1500 0.0017

CROSSLEg 2 231.799 0.0227 1.0598 1.0594 291.700 291.670 7.778 0.0059 0.0001

CORNER 4 231.799 0.0227 1.0598 1.0594 291.700 291.670 7.778 0.1500 0.0017

SETTLINg CHAMBER 263.329 0.0200 1.0597 1.0594 291.700 291.677 6.846 6.3033 0.0560

CONTRACTION 263.329 0.0200 1.0578 1.0575 291.700 291.677 6.859 0.0098 0.0001

TEST SECTION 25.260 0.2148 1.0578 1.0244 291.700 289.034 73.141 0.3250 0.3218

Table 3. Losses, Proposed Circuit

b) Open Test Section, Power Point
LANGLEY 4X7 TUNNEL -FAN DESIGN CASE, OPEN T/S, 50 PSF, OCT. 30/84

TEST SECTION CONDITIONS

MACH NUMBER - 0.1840

" TOTAL PRESSURE 1.0375 BARS

TOTAL TEMPERATURE - 291.0000 DEg. K.

" DYNAMIC PRESSURE - 0.0240 BARS

CHORD REYNOLDS NUMBER - 2.1454 MILLIONS

FAN LOSS FACTOR(DPTF/OTS) - 0.7133

TOTAL PRESSURE RISE - 0.0171 BARS

AIR PONER - 3338.6595 KW

EFFICIENCY - 0.8000

(PTFO/PTFI) - 1.0166

" (RMF*SQRT(TRFI)/PRFI) - 1914.7184

CIRCUIT TRANSIT TIME " 20.1294 SEC.

EQUIV. CONTRACTION L. - 9.0000 M.

• PLENUM BLOCKAGE - "0.0000

• TUNNEL MASS FLOW - 1935_8910 KgR./SEC.

FAN INLET UNIT RE. - 1.2359 MILLIONS/M.,

FAN OUTLET BLOCKAQE - 3.0000 PERCENT

FAN DIFFUSER BLOCKAGE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SQ.M. BARS DEg. K. M./SEC. LOCAL T/S

TEST SECTION 25.260 0.1840 1.0375 1.0133 291.000 2B9.043 62.668 0.0000 0.0000

COLLECTOR 28.118 0.1646 1.0375 1.0181 291.000 289.431 56.108 0.3453 0.2777

CORNER 1 79.008 0.0581 1.0308 1.0284 291.000 290.803 19.861 0.1700 0.0172

CROSSLEg 1 79.008 0.0582 1.0304 1.0280 291.000 290.803 19.870 0.0774 0.0078

CORNER 2 86.304 0.0532 1.0302 1.0282 291.000 290.835 18.189 0.1700 0.0144

FAN INLET 86.304 0.0533 1.0299 1.0278 291.000 290.835 18.196 0.0058 0.0005

FAN 86.833 0.0529 1.0299 1.0279 291.000 290.837 18.085 -8.4863 -0.7125

FAN TAILCONE 86.833 0.0522 1.0470 1.0450 292.373 292.214 17.873 0.0861 0.0071

FAN DIFFUSER 141.448 0.0320 1.0468 1.0461 292.373 292.313 10.964 0.2041 0.0064

AIR OUTLET 263.329 0.0172 1.0467 1.0464 292.373 292,356 5.889 0.0000 0.0000

CORNER 3 231.799 0.0195 1.0467 1.0464 291.000 290.978 6.658 0.1500 0.0017

CROSSLEO 2 231.799 0.0195 1.0466 1.0463 291.000 290.978 6.659 0.0059 0.0001

CORNER 4 231.799 0.0195 1.0466 1.0463 291.000 290.978 6.659 0.1500 0.0017

SETTLING CHAMBER 263.329 0.0172 1.0466 1.0464 291.000 290.983 5.862 6.3033 0.0566

CONTRACTION 263.329 0.0172 1.0452 1.0450 291.000 290.983 5.869 0.0100 0.0001

TEST SECTION 25.260 0.1826 1.0452 1.0212 291.000 289.072 62.206 0.3250 0.3227

•" Table 3. Losses, Proposed Circuit

.... c) Open Test Section, Acoustic Design Point
52

Assumed Conditions

PSCo-- 2116 PSF

TSO) = 60°F

i.

Grid at Corner 3

Honeycomb and 4 Screens in Settling Chamber

New Fan

"Acoustic" Turning Vanes in Corners 1 and 2

Acoustic Lining in Crossleg 2 (Settling Chamber)

and Test Section __

Test Section

Quantity

Closed Open

Mach Number 0.285 0.217 0.184

Dynamic Pressure (PSi=) 120 70 50

t

Fan Speed (RPM) 182 158 135

Loss Factor 0.266 0.713 0.713

Fan Efficiency (%) 0.82 0.80 0.80

Fan Power (HP) 6,900 7,300 4,500

Fan Pressure Ratio 1.0144 1.0230 1.0166

Mass Flow (kgls) _J-_'/(_ • 3343 2247 1915

*

_=Tol 288 K, _= Pol 101325 Pa

Table 4. Loss Summary, Proposed Circuit
53

Existing Proposed

Tip Diameter 12.5 M 12.5 M

!= Hub Diameter 4.9 M 7.0 M

Inlet Guide Vanes

J None 5

Rotor Blades

y _ 9 19

Stators

7 7

Table 5. Comparison of Existing and Proposed Fan Geometries
LANGLEY 4X7 TUNNEL - CLOSED T/S, 120 PSF, ORIGINAL XLEg 2, 0CT. 30/84.

TEST SECTION CONDITIONS

MACH NUMBER - 0.2850

TOTAL PRESSURE - 1.0721 BARS

TOTAL TEMPERATURE - 293.7000 DEg. K.

DYNAMIC PRESSURE - 0.0576 BARS

CHORD REYNOLDS NUMBER - 3.5796 MILLIONS

FAN LOSS FACTOR(DPTF/QTS) - 0.2653

TOTAL PRESSURE RISE - 0.0153 BARS

AIR POWER - 5114.4664 KW

EFFICIENCY - 0.8200

(PTFO/PTFI) - 1.0144

(RMP*SGRT(TRFI)/PRFI) - 3343.1790

CIRCUIT TRANSIT TIME - 11.8220 SEC.

EQUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAGE - 0.0000

TUNNEL MASS FLOW - 3478.4118 KgR./SEC.

FAN INLET UNIT RE. - 2.2069 MILLIONS/M.

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER BLOCKAGE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SQ.M. BARS DEO. K. M./SEC. LOCAL T/S

TEST SECTION 29.305 0.2850 1.0721 1.0133 293.700 289.005 97.061 0.0000 0.0000

T/S DIFFUSER 29.614 0;2817 1.0721 1.0146 293.700 289.113 95.942 0.0775 0.0758

CORNER I 79.00S 0.1018 1.0677 1.0600 293.700 293.093 34.898 0.1700 0.0227

CROSSLEg 1 79.008 0.1019 1.0664 1.0587 293.700 293.092 34.941 0.0775 0.0103

CORNER 2 86.304 0.0932 1.0658 1.0594 293.700 293.190 31.978 0.1700 0.0190

FAN INLET 86.304 0.0933 1.0647 1.0583 293.700 293.189 32.011 0.0058 0.0007

FAN 86.833 0.0928 1.0647 1.0583 293.700 293.196 31.816 -2.4013 -0.2656

FAN TAILCONE 86.833 0.0916 1.0800 1.0737 294.900 294.406 31.489 0.0817 0.0089

FAN DIFFUSER 141.448 0.0561 1.0795 1.0771 294.900 294.715 19.290 0.2024 0.0083

AIR OUTLET 263.329 0.0301 1.0790 1.0783 294.900 294.847 10.354 0.0000 0.0000

CORNER 3 263.329 0.0300 1.0790 1.0783 293.700 293.647 10.312 0.1500 0.0018

CROSSLEg 2 263.329 0.0300 1.0789 1.0782 293.700 293.647 10.312 0.0058 0.0001

CORNER 4 263.329 0.0300 1.0789 1.0782 293.700 293.647 10.312 0.1500 0.0018

SETTLINg CHAMBER 263.329 0.0300 1.0788 1.0781 293.700 293.647 10.312 6.3031 0.0745

CONTRACTION 263.329 0.0302 1.0745 1.0738 293.700 293.647 10.352 0.0092 0.0001

TEST SECTION 29.305 0.2842 1.0745 1.0159 293.700 289.032 96.781 0.0412 0.0411

Table 6. Losses, Proposed Circuit, Original Settling Chamber Area

a) Closed Test Section
LANGLEY 4X7 TUNNEL - OPEN T/S, 70 PSF, ORIGINAL XLEg 2, 0CT. 30/84.

TEST SECTION CONDITIONS

MACH NUMBER - 0.2170

TOTAL PRESSURE - 1.0471 BARS

TOTAL TEMPERATURE - 291.7000 DEg. K.

DYNAMIC PRESSURE - 0.0334 BARS

CHORD REYNOLDS NUMBER - 2.5310 MILLIONS

FAN LOSS FACTOR(DPTF/QTS) - 0.7122

TOTAL PRESSURE RISE - 0.0238 BARS

AIR POWER - 5444.2288 KW

EFFICIENCY - 0.8000

(PTFO/PTFI) - 1.0230

(RMF*SQRT(TRFI)/PRFI) - 2247.1059

CIRCUIT TRANSIT TIME - 17.7033 SEC.

EQUIV. CONTRACTION L. - 9.0000 M.

PLENUM BLOCKAGE - 0.0000

TUNNEL MASS FLOW - 2283.3927 KgR./SEC.

FAN INLET UNIT RE. - 1.4556 MILLIONS/M,

FAN OUTLET BLOCKAGE - 3.0000 PERCENT

FAN DIFFUSER BLOCKAOE - 8.1803 PERCENT

AREA M PT PS TT TS U LOSS FACTORS

SG.M. BARS DEg. K. M./SEC. LOCAL T/S

TEST SECTION 25.260 0.2170 1.0471 1.0133 291.700 288.978 73.899 O. O000 0.0000

COLLECTOR 28.118 0.1939 1.0471 1.0200 291.700 289.524 66.081 0.3462 0.2781

CORNER 1 "79.008 0.0683 1.0378 1.0344 291.700 291.428 23.343 0.1700 0.0172

CROSSLEg I 79.008 0.0683 1.0372 1.0339 291.700 291.428 23.358 0.0773 0.0078

CORNER 2 86.304 0.0625 1.0370 1.0341 291.700 291.472 21.381 0.1700 0.0144

FAN INLET 86.304 0.0625 1.0365 1.0337 291.700 291.472 21.392 0.0058 0.0005

FAN 8b. 833 0.0622 1.0365 1.0337 291.700 291.475 21.261 -8.5107 -0.7125

FAN TAILCONE 86.833 0.0610 1.0603 1.0575 293.598 293.380 20.920 0.0848 0.0070

FAN DIFFUSER 141.448 0.0374 1.0600 1.0590 293.598 293.516 12.830 0.2036 0.0063

AIR OUTLET 263.329 0.0201 1.0598 1.0595 293.598 293. 574 6.890 0.0000 O. O000

CORNER 3 263.329 0.0200 1.0598 1.0595 291.700 291.677 6.846 0.1500 0.0013

CROSSLEg 2 263.329 0.0200 1.0598 1.0595 291.700 291.677 6.846 0.0058 0.0001

CORNER 4 263.329 0.0200 1.0598 1.0595 291.700 291.677 6.846 0.1500 0.0013

SETTLINg CHAMBER 263.329 0.0200 1.0597 1.0594 291.700 291.677 6.846 6.3033 0.0560

CONTRACTION 263.329 0.0200 1.0579 1.0576 291.700 291.677 6.859 0.0098 0.0001

TEST SECTION 25.260 0,2148 1.0579 1.0244 291.700 289.034 73.141 0.3250 0.3218

Table 6. Losses, Proposed Circuit, Original Settling Chamber Area

b) Open Test Section
Attenuation, DB

i

TC Turning Vane TurningVane Concept Similar To DNW (Rolled Plate Vane)

Hz ProposedBy 8BN 1.6 M Chord 2.5 M Chord 4.0 M Chord

(Profiled

Vane) z_ z_ z_

125 8 0 8 4 4 8 0

250 12 6 6 10 2 13 -

500 10 14 - 13 - 10 -

1,000 10 10 - 10 - 10 -

2,000 10 10 - 10 - 10 -

4,000 5-10 10 - 10 -- 10 --

8,000 5-10 9 - 10 - 10 -

Table 7. Comparison of Acoustic Turning Vane Concepts
•

...

FIGURES J

57
58

tl

Settling Chamber Redesigned

Acoustic Treatment Fan

_ iiiiiiiiii!iiiiiiiiii!iiiiiiiiii!iiiiii:ii_:iiiiiiiiiiiii _iii?iiiiiiiii!i!!: ___,,_'

f " AcCOUS_l_al/yTreated

Turning Vanes Acoustically Treated

Test Chamber

Figure 1. Scheme B (Significant Fan Redesign)

Acoustic Treatment of the 4x7 m Tunnel Circuit

FromReference 3
59

Open Test Section

Power Point

. 1.030

® Specified Operating

Point

1.025 Surge Line _ _ Fan Design Point

70 psf

1.020 Open Test Section Acoustic Design

Point

PR

160

Closed Test Section

1.015 Power Point

120 psf

185

1.010 Open

Test Section 130 180

150 N (RPM)

1.005

Closed Test Section

1.0 -T I I I I '-,

q !000 2000 3000 4000 5000

• _ _ (kg/s)

Figure 2. Approximate Fan Performance
6O

3O

J

2O

1st Bending

[.z3

P

1st Torsion

i

0 I

100 182 200

RPM Fan

Maximum

Speed °

Figure 3. Fan Blade Interference Diagram
Project No.

',L DSMAEngineering Corporation Figure 4. Project Schedule- Construction 4054 _, Orlando, Florida Project Feasibility Study Date Nov. 2184

Title _ Modificabons To The 4x7 Meter

Tunnel For Acoustic Research Sheet 1 Of 1

Description 1 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18

FAN _:.i:.!:.i::_::_:: i_::_::_! :.i_::_::_!_!_::_i_i_::_::_._.:.i:.i:_ __:_::_i_::_!:.;:_i:.i:.i :__!_._!_::_i_::_!_:._:._::_::_i_:: i_!_i_i_i_i_ :._i_:.i:.i:._:i!i :.i_!_i_i_i_ : _:

Fabrication

Drive .ouGearbox ,,no ............ i Existing Fan Disassembly

Site Installation _ _ ______=_ _=_'__i_i_i_!_i_i_i_i_!_i_'_'__ i_'_'_'_'_i_'_'_i_ii!i!iiii

SETTLING CHAMBER iiiiiiiiiiiiii!i!iiiiiiiiii ! ==:::::::::::::::::::::::::;

Shop Fabrication :.:.:::.!:.::il .:_:E:_:_:E:_:E:E:E%

::::::::::::::::::::::::::::::::::::: .............

Shop Fabrication _:::_:_:_:_:_:_:: _i!i_i_i_i_i_ili_iii_i_i:i

Site Installation ........... _:_:_:_:_:i:_:_?_:_:_:_:_?_:

MRemoval ode, Prepa of Existing ration Bui, Vanes ding ::_iiii!iiiiiiiiii_i!i_iiiiiii_ _ _ _i _iiiiiiii!iiii.,E!_!_i_!ii_i_!iiiiii_i

Shop Fabrication _ _ ?_::_:_ _:_::__::__:_, :_%_:_:_:_:

Site Installation - Vanes _ _ iiiii!i!iiii'_i_' :_!_:_:_:_:_:_:_

- Panels i_i_i_i_::_!_:,:,_::_::_::_:

:i:i:i%!$_:::::::::::::::::::::::::::

RELOCATION OF CONTROL ROOM i,i,:-_::_::_,_,:._i_i::i::i iiiiiiiiiiiiiiill iiiiiiiiiiiiiiiiiiiiiiiill _i_!!i:ii_!iiiii_,!_,i ,i',i'_'_i iiii::,i!iii;ii!iiiiii _!_,ii',_'_iiiiiiiiiiii_,ili :_ii_i_ :,i',ii iiiiii!iii :: _i'_i'_iiiii'_ii'_iii!ii!!i' ::i 

STING SUPPORT AND MODEL DR'VE iiiii!iiii!iiiiiiiiiii iiiiii!iiiii!ii!i ii i!ili:_iii!iiiiiilii

Long Lead Hardware :::::::::::::::::::::::::::::::::::::::::::::::::::: ::::::::::::::::::::: iiiiiiiiiiiiiiii!i;::::!ii::::::::::: ::!:: :::

Shop Site Assembly Installation Fabrication Tests and -ModelSting _ Model

FACILITY CHECKOUT

FACILITY COMMISSIONING __

..

..

DRAWINGS I

63
, I 3 ! 2 I 1

" |

/

NEW 8U,LD/tG / 55 "O"

FO_ aCOUSTIC

MODEL PREP J

.__t

I

I 1\ I

I

/1 , _'O.

ACOUSTIC OETTREATMA,ENT

,.O. ? -- -- -- -- J f\l/' I To..... t °VASN.. .--...... "

FOR N_W FAN _ x l \ ] { [ DWG NO. LD-544307 -I

CONCEPT SEE _-_ _, _.- I 'i_ ___

,%*gZ%_ r _-._ r- : -

,,os

;°'

;Lo-54_so6sMr

"

,___1 _' I _

I

'

co",O

LD'544308 _ I 8Z x ..... _"I', 1"-

i

/ II ,o.o.,.,:O,o.

/ i

_ FOR DETAILS OF AEOUSTIC J

TREATMENT TO 5_rTTLING CHAMBER

SEE DWG NO. LD'544304 .J _),#,0_, "_

DSMA Engineering Corporatio_ _ ' .... ,-',, "-- , ........ ,"" < --.o... :_.

.. Orlando, Florida -'_.'..J.'.%'T'...: _" _ _ .:, _ ._:_,_^, : 2

/

il' _"°...... " -" I_ LD. 544._o_

4 3 I 2 *DSMAv_ _054-00,

I

• t €
• i 41 •

, I 3 I 2 I ,

5TA_ 601

5TA390"3

SECTION4 _ 5ESTIGN _ _ SE_,_C_ _ ......... ..,_...

STAJS#3"

5 J_,_ET GI,_,E vA',£5_ 6EAR BOx _-/.DES VANES l-.-I

/

r • 1 i i f

\_-.L- -/- --i . r---, --; _ ....._-_-_--<_--=-----_-----_________:__

_[ : , : _=:_; - --_ \

)

i ! zl : ............ ;...... :.-, . ,

'. " , I $'1 --- ! I _ ''

........... _>.--1..t_l....

- _"............ •.............. _ ........... • t ..... ;.......... ; '

i " ' ": ' :_ 1-_" "P_ ] " "

f--- ,

23:e" _ 5-6" _ ........ _i-2' 37._q" ..........

STA 325"-G "'_ _- St4 J33"-4"

I. -'_'/- ........

' :)SMA Engineering Corporatior ..... t'"i ........ i ='' =.--'".-.= _ .... _....

JA!l OrlandoFlor , ida 1 I I r'..l,=...: V" _ _ :'.:,, ,.:_¢ y-INITIAL _"_,'v2EPT

' 1 ._+.......,,...., -" lz l_ _<_3°z I

4 3 [ 2 _r #of4 I.._M,J,N£ DJ2_J-_C2
, L

10_'-4"

DSMA _,-,g;_,_,_r,_.._. co_,C°rp°rati°n --_._ _- _ -_'_'- ' =" ' .......... _. _ _ _ _ "_ _

I _!'1 l,,_ _ _,_A_'_.!: _:r 4x7 M TUNNEL. STUDY

"_I 1_,I -" I"_' LD-.54430,3

4 3 I 2 S_4OF,=I _SMA N204054"O02
• •

B

A

\

SECTION B-B

.. ---.

""""""'0 Do" _

2

--- 2

Orlando. Florida

-.._--..---

OSMA Engineeri flI8 Env__ ~g Corporatio DI!J ConoltUClOB

3

3

'H.j5'"

rrp (10 BLADES)

._ L

I

J------- s:.§:

ReTCR

It£VISIOHS

4

4

,

I

1

I... ,J,'··oo·

A

B
, ! 3 1 2 I ,

IPL_N_T G[AR _ T ._]P FAN ROTORHUB

66 ' /

,+ --;------- -I i

N£EDL__AR#_ ,,N,ll E919 Cia..*30000 " - ---/-_ --r-" '/ !!

................. , ! ! ! ,, f

, iI /"

_d2U_""M SUN <'" 'UP,,R, . ;1 / rl ' ,

f _ _ \-J.." . .. /, ".,_-_.q-.

, ! \ ;A"\_ I'1 _1._

, ! i--:--<_-.-I::-:_i I ..\'.\ \ _+..+._--::_-,

I ............ _.,__.... _ _ i

--L / / =lk-_,".2. " . .J

S_Uq.GfM+ f_ r 30P I "

OIN_AR_._ !13 K._JDP_ .1! ..... ... .......... _1 __

TAPER8EARI_IGCdZ,_,_O_QQ_Lb

DSMA EngineeringCorporatior ......................... /."_0._,_._,_.._-_._M,, r:<__, ,_o.

Orlando, Florida ..... V_- ;_"_"_ COAXIAL jEARB_X CONCFPT

4 3 I 2 s_r ao_4 1DSMA 'vP._O_4-OO2
I

• •

4 I 3 I 2 I 1

C

r ,

T T T

'" ./

~" 1

. ! -,

~i 1 '-' '-' "J J '-" 1'-" '-' '-/ '-' '-' -1 ! I :

I: :

I ; .' ~"'-. ,

"'-.' I

I ,

~" i

, , B - '" "

B 1'." , - FLAof PANEl

12"· O' THIe," .·Y~

~" !

f- , 1 i

"'''' i

~c::rU;~:~fL?-~

f-~I '" ! -I

1 "'.-

!

TI,.,Rfl/IN6 VANES N r ., , -

~D .. u/ 1-0 --=~!-' - ..- .. ./

- /

I, ! -- r--H-; I--

I~ J.

1

S

1

.. S~A ..E -¥4"· (0'

J V</ I /

). I--1/ "/ \

'l

I/l'l I ' ... AT __-- I ) .. j C 6.:.TT!N - iJrAN£L5 I )

l/.~ / \ )! ,r""-!>O I \

v/ I \ I- .. I - ------ ._- ..

.. V/ '" ] ~II I-r)ij I , .,

I

I

A l/. // I ~A I A V/ I 1 I

"""- ""- ;ONCR[Tt rLCX;VI 1 1 1

A-A ~A --- 50CTION

0 seA.. ! "Y4-· ':0

SECTIONAL PL AN VIEW 40

SCALf !-& •'·0·

""""""D ..- ,- "'notW. AlJlOfiWJTlCI .uG .ACI ACIIIIMIT1tAfICIIt

DSMA Engineering Corporatio ~,- ~, - -.1.__

VoI"IGl.........t,ll('Mct..f'(.

.........e- ". ~lM\

BE end CoIl8l1UC:t<n =:••~:- (:::.::==::' ~..;., .-.\'':T:; .H\D ~I,.·•.\E:.. STWY Orlando. Florida _. VF-:::;" _-:'~~-:ST<' 7J.i.~~r.~EfjT . -, , -. -~ .. bQ;.544304 lI[V1SlONS w - .1_- .. - - "=,,or, -_.- Il[YTSIONS w .- aft _.- -- - - - - 4 3 I 2 T 1 :Y5MA \Q ;';05';-005
4 I I

B

A

0;P

..{..!

'I '

f :il

SEcT/O'" A·A ;'YJr4·:~ 9~·

SCALE: ~4~/:O~

:1"

I

I

I

I -

'~ll ~'1 ARRAN5[II[NT PO$$18LE

•. - O~ CON rROLS,i CON~OL!

, '"

~"-~ ~: CJ --r---~

J., L,,-LjJ .... - .... DOOR wITH

AIRLOCK

-

--~._--- ----r _

rc_==nhl ==nr====n:~::::::::--'1P1 ~t==

-----/--

IrEsr CHAMBER I .

Hl---1---

(j) --1-----

J

- ,-' -_.~-==tI=::=::=.$~~.4JM=,==::=:j·f===t--

i _I I_I~:=-l~

1t=1-It:=if--i-~ IF==:: I~ is:::::-- J=

A

B

-

I

.. (::.:---.:~ ""'..J, ~~, -...,,\..V~L 5;U;f

-. "V---~ ';;"'EW ~·:::W=O_ =CCM LO

: •. •:-;" ... •• LO- 544305 - - .... IO~1 __

- - 1~SM.l \c, ,) .JC54,OC9

.T _

2 I

Orlando, Florida

DSMA Engineering Corporation am EngiMers lIl1d Conotruetor.

3

I. • •
• •

4 I 3 I 2 I

-- l.$f~:o M"'" ~~.-aTUl1CII

-"_. (;::.:---::' "::4X 7 METER WIW TI.Jf'.;NE~ srwr _ _ if F '=" 4C(lfs'l~(

B

5FCTlON A -A

S:AL£: yi. ,:.00

,..-- SEE TYPICAL CROSS-seCTION OF·FAfHI"-6

T

TYPICAL CROSS'SECTION OF F"';;·,\G

SCALe .}r/·'-O·

i

riJ

DSMA Engine«lng Corporation

Engn«s _ ConotNc:torw

:- s[£ r'fPlGAL

1 [ROSS SECTION \ JF ,J, ~,·.G

f

.9

0---

0--"--

SGI.L£ : ti'· /-0'

lAIR FLOW>

B

-

-.

3 I 2 I

::'0< > LQ:§44306

SHUT' O'l 1 DSMA N9 4054·004
4

I3

r2

(

1

cp VJ !i 1

T

I

1

I

I

, ,II

;!

/ J:O"THICIf WfD6E fMNfU

B

ON C(ILING TRUSSES

/

-

t ..••E< I

SECTIONA -A FRey SI"t££T I

A

B

I--A

I. '.

•
•

4 3

_~!~__FV~_?_~E-:C_ON__rF1O__L~~I -:- !_l r_\( a

t r"'NfL

B

A

'12"

'..

''';

.~

i

@

L SEE DETAIL A

lAIR FLOW)

wIRE I,IESH BACI<#IG

B

A

FIRST CfY?N[R SECTIONAL . PLAN VIEW

_ .... Uf..... 1l£V......

3

DSMA

ftm Engineenng~~..::..:: . "A~-rBtion __

~----~.

2
3

._- -------~_4

I

A

nccTRtCAL CONTROL

HARNESS

-~-i~

J~-':'l

U

ROTARY JOINT· J

COOLANT AND OIL

StJPPtr AItI(J (JIfAIN

/

(XISTING FtOOR LEvEL

ROTARY JOINT·'

SEE DETAIL A / (SEE SHUT 2)

-~--~ --..........,

::EE DETAiL. 8 (so; SHeer Z J

..' . ..

I

. .J

L~~~tf-- ---,-----.

'L.---l-_-"/ "' -_+'

12:"·

.---------

A

I

-',eY' LD·544308

SHUT /OF:3 1 DSMA ",fJ 04054-007

'1&"10 ...nGIIlII. ~.=o.-:,....-nMftM co ......... .,. l]llld

~:.:=::'::' "=' 4x7M TlNJEL STUDY

V-,=" ROTARY STifliG ARRANGEI.£NT

DSMA Engineering Corporation Hm EngNww - ConolJuctarI

3

.-

" -.... -

.. rio
...... , I 3 I 239" I ,

_8.S"

LOC_N_.F "_ [ lOlL 2"TS'COOLANT ,'ENT$

. /_',..,,,/_.. _, 1- • _ __

-'

_ -q_-llrn ' " ,'q\.\"' ._ _ /I_OT TO _ALE)

/,-°,.... =,=_ I ..; .,

,\ 7/

.................... DSMA Engineering Corporation _ _" ....... _ ........ - '_" _...,0,"'_",.:,,,,_'_'

"- 1_¢_ _.--._-_.-.._I _. l!:.i_-:=:: "7,_" 4x TM TUNNEL STUDY

i.C.... _ o,_._,_ __ ._..m: %7- "= _ _0_ #OrA#Y_O._T

[ .... _ ,-.,-:1, ...... [': :;C, I"_.... ILD-544308

4 3 T 2 _ s,_. 3 _r3 1 DSMA D -;0..58 007
4 3 2

B

WAT[R. Dt. CON7JQ. ,&

IIVSTRUIt/ENTATIOH llNCS

"·0" DIA

B

A A

-...- .....-4

.-- - ......... 3

DSMA Engineering Corporation

lim =:::~

2

---- ---- _.

'. ,. '.
•

4 3 2

.- --.:8.=.:'.:.' _

B

A

OIL

SIJPI'Lr

A

fLECTRIC

WOTOR ?

+

I

'\ \ ~\

- - '--\

'" "'" II .-/

~:.:::. - - -~ -~ -- .

+

B

SECTION A·A

+

A

j

seA/ENGE SYST[IJ

ROrA~Y SELtCTOlf VAL ..!

\

OIL

/1ETURN

U~P£R

5CM[N6f :l01#7

'. TrP 4 PLACES

LONER " SC.-.'!"JS! ;'OIlT-'::'

~"" 4 :>~ACES

SECTiON C-C

B

A

u11ClJW. fo[JlOfW1T1CI AMD sr,ra ADIIIMITU11DIII ~UIIUloU!C"Cf"'111

_(lIIl •• :>foU

oo;::'ROTOR DRIVE GEA"SOX CexvCEPT

_ -::'2N. bQ;t4...J309

;,.fer OF 1051,/,4 ",. i).JL54-CC6

----- -...~.

---

2

Orlando, Florida

OSMA Engineering Corporation am Eng~ and Conllructon

3

MViSIONS

4
1. Hcport No.

NASA CR-178079

Standard Bibliographic Page

12. Government Accession No. 3. Recipient's Catalog No.

4. Title and Subtitle

Modifications to the 4x7 Meter Tunnel for Acoustic

Research--Engineering Feasibility Study

7. Author(s)

9. Performing Organization Name and Address

DSMA Engineering Corporation

Orlando, Florida

5. Report Date

March 1986

6. Performing Organization Code

8. Performing Organization Report No.

4054/R128

10. Work Unit No.

11. Contract or Grant No.

NASl-17892

•

f-,------------------------'--------j 13. Type of Report and Period Covered

i2. Sponsoring Agency Name and Address

Contractor Report National Aeronautics and Space Administration Washington, DC 14. Sponsoring Agency Code

534-03-12-02

15. Supplementary Notes

Final Report

Langley Technical Monitor: S. R. Barringer

16. Abstract

The NASA-Langley Research Center 4 x 7 Meter Low Speed Wind Tunnel is

currently being used for low speed aerodynamics, V/STOL aerodynamics and, to a

limited extent, rotorcraft noise research. The deficiencies of this wind

tunnel for both aerodynamics and aeroacoustics research have been recognized

for some time. Within the FY 1984 NASA Construction of Facilities (CofF)

Program, modifications to the wind tunnel are being made to improve the test

section flow quality and to update the model cart systems.

A further modification of the 4 x 7 Meter Wind Tunnei to permit rotorcraft

model acoustics research has been proposed for the FY 1989 CofF program. As

a precursor to the design of the proposed modifications, NASA have conducted

both in-house and contracted studies to define the acoustic environment within

the wind tunnel and to provide recommendations for the reduction of the wind

tunnel background noise to a level acceptable to acoustics researchers. One

of these studies by an acoustics consultant, Bolt, Beranek and NeWman Inc. (BBN) ,

has produced the primary reference documents (Refs. 1 and 3) that define

the wind tunnel noise sources and outline recommended solutions.

As wind tunnel design consu1tatns, DSMA Engineering Corporation has been

retained to conduct a conceptual design arid feasibility study for the practical

application of the modifications recommended in Refs. land 3. This report

covers the results of this study.

17. Key Words (Suggested by Authors(s»

wind tunnel design

wind tunnel fans

acoustic treatment

18. Distribution Statement

Unclassified - Unlimited

Subject Category 71

19. Security Classif.(of this report)

Unclassified 1

20. Security Classif.(of this page)

Unc1assifip,t

21. No. of Pages \22. Price

85 lAOS

I

For sale by the National Technical Information Service, Springfield, Virginia 22161

NASA Langley Form 63 (June 1985)