NASA Contractor Report 189736

/N- o_-- -J

0

Modifications to Langley 0.3-m TCT Adaptive

Wall Software for Heavy Gas Test Medium

Phase I Studies

A. V. Murthy

ViGYAN, Inc.

Hampton, Virginia

Contract NAS1-18585

December 1992

NASA

National Aeronautics and

Space Administration

Langley Research Center

Hampton, Virginia 23665-5225 Assoc i ates )

(NASA-CR-!89736) MODIFICATIONS TO

LANGLEY O.3-m TCT ADAPTIVE WALL

SOFTWARE FOR HEAVY GAS TEST MEDIUM,

PHASE I STUDIFS (Vigyan Research

42 p

N93-16710

Unclas

G3/OZ 0141130

MODIFICATIONS TO LANGLEY 0.3-M TCT ADAPTIVE WALL SOFTWARE

FOR HEAVY GAS TEST MEDIUM

The scheme for two-dimensional wall adaptation with sulfur hexafluoride (SFo) as test gas inlthe

NASA Langley Research Center 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT) is presented.

A unified version of the wall adaptation software has been developed to function in a dual gas

operation mode (Nitrogen or SF6). The feature of ideal gas calculations for Nitrogen operation is

retained. For SF 6 operation, real gas properties have been computed using the departure function technique. Installation of the software on the 0.3-m TCT ModComp-A computer and

preliminary validation with nitrogen operation were found to be satisfactory. Further validation

and improvements to the software, if necessary, will be undertaken at a later date when the 0.3-

m TCT is ready for operation with SF e gas.

INTRODUCTION

The Langley 0.3-m TCT ]"is a unique wind tunnel facility for testing two-dimensional airfoil

models at transonic Math numbers and flight equivalent Reynolds numbers. The high Reynolds

number capability is achieved by using cryogenic nitrogen gas as the test medium. The 0.3-m

TCT, since its first proof-of-the concept studies in 1976, has undergone several major changes to

provide additional testing features. In its present form, the 0.3-m TCT has a 13-inch square test

section with adaptive wall capability for top and bottom walls and a sophisticated side wall

boundary-layer removal system. These features make possible testing of airfoil models with a

greatly reduced level of wall interference.

i

The application of the cryogenic concept has been highly successful in simulating the much

needed high Reynolds number capability at transonic speeds. Many cryogenic wind tunnels have

been built in the last decade and are being used routinely to test under high Reynolds number

conditions. Presently, an alternative approach of using a heavy gas in place of the cryogenic

nitrogen to provide high Reynolds numbers is under consideration. The use of' heavy gas per-

=nits operation under ambient temperature conditions making model design, and force and pressure measurement instrumentation simpler. Also, as demonstrated by Smelt 2, the power

requirements will be lower.
Thepresent heavy gas feasibility study at Langley uses sulfur hexafluoride.(SFo) which is about

five times heavier than nitrogen/air. However, at a given test Mach number, the increase in

Reynolds number is about two times due to lower speed of sound ( 30% of air) and lower viscosity (80%). The use of SF e also poses much less environmental concerns compared to CFCs.

However, the effect of the real gas properties of SF 6 on the flow around the model and on the

shock location at transonic speeds is not well known. The different value of the ratio of specific

heats and other real gas effects may require corrections to be applied to the test data for valid

comparison with the nitrogen test data. Therefore, to facilitate a comparative study between

using cryogenic nitrogen and SF e, the 0.3-m TCT is being modified to operate using either gas

mode. The proposed modification permits a direct tunnel-independent aerodynamic evaluation

of the two different methods of generating high Reynolds numbers.

The objective of the present work is to study the aspects of using the 0.3-m TCT adaptive wall

capability with the SF e test gas. Necessary modifications to the adaptive wall testing technique

in support of the aerodynamic evaluation studies using SF e gas have been considered. The adaptive wall software currently in use has been developed specifically for using nitrogen gas as the

testing medium. For use with SF o gas as the test medium, it is necessary to incorporate changes

to account for the thermodynamic properties of SF e and other operational features. The new

version of the adaptive wall control software has been developed to incorporate the following

main features.

a) Easy switching between two test media (Nitrogen & SFo)

b) No major changes at operator end; thus avoiding operator retraining.

c) Retain the same program structure and add additional features

to facilitate easier maintenance of the software.

This report describes the methodology used in modifying the software for the dual gas mode and

provides details of the modified software developed during this first phase of the study. Limited

tests were made to check the performance of the software. Final checking and changes, if

needed, will be made when the tunnel is ready for operation with SF e gas.

Nomenclature

.40,4

a

Constants in expression for constant-pressure ideal heat capacity (Eqn. 2)

Speed of sound (meter/second)

i t

,

it

.-
02,S

b

b2,6

Cp

• O

(-p

C

Y

C °

Y

¢2,6

H

k

M

N 2

P

R

S

SF 6

T

T

C

U

V

W

Z

P

Constants inequation of state (Eqn. l)

Constant in equation of state (Eqn. I)

Constants in equation of state (Eqn. I)

Constant-Pressure heat capacity

Constant-Pressure Ideal heat capacity

Constant-Volume heat capacity

Constant-Volume Ideal heat capacity

Constants in equation of state (Eqn. 1)

Enthalpy (Joule/kmole)

Constant in equation of stati_ (Eqn. 1)

Much number

Nitrogen ......

Pressure ( Newton/meter z)

Universal gas constant (,= 8314.34 Joule/(kmole Kelvin)

Entropy (Joule/(kmole Kelvin)

Sulfur hexafluoride

Temperature (Kelvin)

Constant in equation of state (Eqn. 1)

Velocity (meter/second)

Volume (meterS/kmole)

Mo!ecular weight

Compressibility factor

Ratio of specific heats (Cp/C v)

Density (kg/m s)

Subscripts

t Stagnation conditions

v Volume

1 Static conditions after isentropic expansion

0.3-m TCT Adaptive Wall Test Section

"l'he 0.3-m TCT adaptive wall test section (fig. l) uses a flexible wall concept for wall adaptation.

It has rigid side walls and flexible stainless steel plates for the ceiling and the floor. The test
section has a square cross section with a nominal height of 0.33m (13.0 in.) with the flexible walls

set to a flat shape. The flexible plates, 1.82m (71.7 in.) long, are anchored at the upstream=end

and are free to move longitudinally in a sliding joint at the downstream end.

the wall shapes are controlled by stepper motor operated jacks positioned at twenty-one locations

on the ceiling and floor. The wall positions are monitored by linearly variable differential

transducers (LVDT) located at each jack station. The wall Posifi0ns are referenced to the undeflected straight wall shape. In addition to the wall shapes, the wall streamlining algorithm

requires the fluid velocity distribution along the wall. This is calculated from measured wall

pressures at the jack locations from static pressure orifices. The reference test Mach number is

determined by a static pressure measurement near the upstream anchored end of the flexible

plates, This station is 0.8m (31.25 in.) upstream of the model mounting turntable center.

Wall Adaptation Method

Wall adaptation is the process of adjusting the test section wall shapes to nearly free air streamline shapes. Modern methods developed in the last decade are based on the iterative concept

proposed independently by Ferri and Baronty s and Sears 4. The iterative concept treats the flow

over the model in two parts; the real wind tunnel flow inside the test section and an imaginary

flow extending to infinity outside the test section walls. For a test section with flexible walls for

the boundaries, the matching of the flow conditions at the boundaries leads to wall shapes close

to free air streamline shapes. This concept of streamlining was first introduced by Goodyer s to

define the streamlined conditions for a solid flexible wall wind tunnel. The wind tunnel

measurements give the flow velocity and direction at the boundaries. One of these quantities

along with the boundary condition at infinity is sufficient to calculate the imaginary flow. The

other quantity serves as a compatibility check. Iterative calculation of the real and imaginary

flows leads to identical flow conditions at the interface boundary.

2

!'i

3

There are two approaches to applying the iterative concept of adapting the walls. The first

method, known as the interface discontinuity method, is particularly suitable to two-dimensional

airfoil testing. The interface discontinuity method treats the imaginary flow outside the test section ceiling and floor separately. The calculated wall deflections for each wall are then modified

by adding a portion of the deflection for the opposite wall to represent the coupling effects.

The second approach 6 considers the coupling effects by using the Cauchy integral formula and

eliminates the need for separate calculation of the imaginary flows for the ceiling and floor.
Further, the concept can be extended to three dimensional test section using Green's theorem.

For the 0.3-m TCT, the interface discontinuity approach has largely been used. A limited

study 7 using the second approach has been made. The purpose of this study was to demonstrate

the concept of making simultaneous calculation of wall adaptation and residual interference, and

also to identify some of the shortcomings 8 of the wall adaptation method (WAS-I) then in use at

the 0.3-m TCT.

0.3-m TCT Adaptive Wall Software & Present Status

The 0.3-m TCT adaptive wall software has been developed over a number of years by several

authors. The software function can be broadly divided into two categories. The first category

relates to the control of the flexwall hardware, measurement of wall pressures and positions, and

associated safety features. This portion of the software function will not be affected by the

heavy gas operation. The second category, critical to the adaptive wall function, is the algorithm

used to calculate the wall shapes.

As mentioned earlier, the algorithm used in the 0.3-m TCT is based on the interface discontinuity approach. The related studies were primarily developed at the University of

Southampton, England and adapted to the 0.3-m TCT at various stages. Within the concept of

interface discontinuity, different approaches to calculate the imaginary flow are possible.

Reference 9 gives the details of a predictive strategy known as WAS-1, first developed at the

University of Southampton. The WAS-I method was implemented later at the 0.3-m TCT and

has been used in a number of airfoil tests. Reference 10 which describes in detail the 0.3-m

TCT Wall _adjustment strategy software, incorporates the WAS-i method.

Despite its wide use in a number of airfoil tests, the experience at Langley in using the WAS-I

was not encouraging 8. Hence, during late 1988, the WAS-I method was replaced with a different method known as IFLEX. This major revision is not documented and should be considered as an integral part of reference 10.

Reference ! I gives the details of the IFLEX method and a program in HP Basic language. The

IFLEX method creates an imaginary semi-infinite flowfield which has a streamline originating at

i,ffinity and has the same shape as the flexible wall. The method represents (fig. 3) the wall

shapes by a distribution of sources and sinks on a line corresponding to the straight wall shapes.

5
Thesources/sinkstrengthsare determined by the local wall slopes. The difference between the

measured wall pressures and the imaginary flowfield field solution is a measure of new wall

movements required to adjust the walls to streamline shapes. The procedure is again iterative.

Since the top and bottom wall shapes are generally different, separate calculations are made for

each wall.

The IFLEX approach overcomes the shortcomings of the original WAS-I method. Since its installation, the streamlining performance has been found to be satisfactory for the airfoils tested.

However, with a new computer operating system installed during 1991, difficulties were encountered with convergence of the wall contours. This necessitated a complete check-out of the

software before modifications for the SF e operation could be incorporated. Details of the

preliminary check-out program are given in Appendix A. The problem was found to be unrelated to 1FLEX performance but required changes to the Code to work satisfactorily with the new

operating system.

Wall Adaptation for Sulfur Hexafluoride Test Medium

The principle of wall adaptation as used in the IFLEX approach is essentially based on incom=

pressible flow theory along with the Prandtl-Glauret rule to take into account the effect of compressibility. This assumption implies that the flow conditions at the wall be subsonic whereas

the flow over the model can still have regions of supersonic flows and shock waves. This condition is satisfied for most of the transonic testing conditions encountered in the tunnel.

The requirement of subsonic flow conditions implies that the shape of the free-air streamline

shapes are independent of the gas properties for a given test Mach number. Therefore, to first

order, the wall shapes in the fully adapted conditions must be the same for both the nitrogen and

sulfur hexafluoride operation. However, the approach to the final adapted conditions will be

different because of the different thermodynamic properties. For a given wall shape and free

stream Mach number, the measured wall pressures will be different for nitrogen and sulfur

hexafluoride. Correspondingly, the calculated speed of sound and the fluid velocities at the

walls will also be different. However, the values of the pressure coefficients remain the same in

both cases. This feature has been utilized to simulate SF 6 with nitrogen operation. This option

will be helpful during final validation tests.
/

/

Results and Discussion

Properties of Sulfur Hexafluoride

The change in wall adaptation calculation for sulfur hexafluoride gas arises from the fact that the

ratio of specific heats is about I.l compared to 1.4 for the nitrogen gas. The present adaptive

wall software for nitrogen operation uses a constant value of 1.4 for all test conditions. This approximation is adequate since nitrogen behaves like a perfect gas over the operating conditions of

interest.

For SF o operation, the following three options are possible for representing the real gas effects in

wall adaptation calculations.

a. Use a specified constant value of '_sge

b. Use value of 3sv6 based on stagnation conditions.

¢. Perform complete real gas calculations to calculate

the thermodynamic properties.

In contrast to nitrogen, the thermodynamic behavior of SF6 departs from ideal gas even at fairly

low pressures. Hence the calculation of thermodynamic properties require solution of the equation of state and ideal heat capacity equationl2:

i=6

RT _-_ ai + hiT + c i exp(-kT/T c) P II

(v - b) L.., (v - h)_

i=2

(1)

Cp° = Ao + AIT + A2T2 + A3T s + A4T2 (:z)

Reference 13 gives in detail the solution of the above equations and also the procedure to calculate properties after isentropic expansion using the departure function technique. In the present

calculations, the method of reference 13 has been used. Appendix B gives a summary of the

results obtained in reference 13.
Figures4a-eshowthe change in thermodynamic properties of SF 6 over the range of pressures (1-

8 arm.) and temperatures (275-350K) of interest to testing in the 0.3-m TCT. The ratio of

specific heat, "t, increases from about 1.1 at 1 atmospheric pressure to about 1.13 at 6 atmospheres

under ambient temperature conditions. Hence, it would be difficult to fix a priori a constant

value for the ratio of specific heats to simplify adaptive wall calculations. The compressibility

effects increase rapidly with increase in pressure (fig. 4b). With increase in pressure, the acoustic speed (fig. 4c) decreases at a given temperature. Hence, for a given Mach number the fluid

velocity will be lower at higher pressures than at lower pressures. The decrease in density with

increase in temperature is shown in fig. 4d. The specific heat at constant pressure (fig. 4e)

shows non-linear changes for higher pressures and temperatures below about 275 K.. Hence it

appears that to avoid rapid variations in the properties, it is advisable to work at a stagnation

temperature of about 300K or higher.

In addition to these features, the isentropic expansion causes a drop in pressure and temperature.

The determination of the Mach number after isentropic expansion from stagnation conditions

requires solution for the entropy equation along with the equation of state and constant pressure

ideal heat capacity (Appendix B). As mentioned earlier, reference 13 gives a computer program

to calculate the isentropic expansion. Figure 5 shows the Mach number after isentropic expansion from an initial stagnation condition of 8 atmospheres pressure and 300K temperature. The

Mach numbers obtained from real gas calculations are higher than the values using a constant

value of "I based stagnation conditions. The differences are smaller at lower Mach numbers.

The use of heavy gas though requires higher pressures to increase the Reynolds numbers. To account properly for departure from ideal conditions, it is necessary to retain real gas calculations

in the wall adaptation process in the initial studies.

Sin_plified calculations based on a fixed value of "/may be possible after some experience is

gained. While such a simplified calculation may be adequate from the wall adaptation process,

the residual errors in the Mach number may be of uncertain magnitude if different types of calculation are performed for tunnel measurements (ModComp-B) and wall adaptation (ModCompA). Hence, in the present work, complete real gas calculations based on the departure function

technique have been implemented. Further modifications to provide an option for using a fixed

value of '/can be incorporated.
Program Implementation

A Fortran program suitable for implementation on the 0.3-m TCT ModComp-A computer was

developed based on the method described in reference 13. The program was validated on a HPworkstation before installing on the Modcomp computer and integrating with the adaptive wall

software. The original version of the program presented in reference 13 uses double precision

calculation to solve the transcendental equations. It was felt that the double precision calculation may not be required in a real time environment. Further, double precision is not compatible with the remaining calculations, performed using single precision.

Table la compares the results of single and double precision calculations on the 0.3-m TCT

ModComp 16-bit computer for a high pressure test case. The difference between the two results

is not significant, implying that the single precision calculation is adequate. Table lb and lc

show examples of single precision calculations for stagnation pressures of 0.6 and 6 atmospheres

respectively. The results are also compared with results obtained on a HP workstation for validation purposes. However, using single precision calculation requires the convergence limits to be

altered suitably. A typical value of convergence used was 10"6 for the ratio of the change in -

parameter value to the initial value between two iterations.

Program Integration:

The real gas program discussed above was integrated with the adaptive wall software described in

reference I0. The program integration required several changes to many subroutines so that the

integrated software works in the dual gas mode. Appendix D gives a summary of the various

programs and subroutines in the modified software. A source listing of the modified and new

programs added is presented in a separate report. The program is now presently installed on the

following partitions of 0.3-m TCT ModComp-A computer.

a. Source files ... Partition ESL

b. Object files ... Partition EUL

c. Load files ... Partition ELM

The start-up and execution procedures remain the same except the load module is assigned to the

new partition by command//ASS LM ELM. No changes have been made in the OAP system.

9
In the present version, the software developed has the following features.

a. Functions in both the nitrogen and SF o modes.

b. Choice of the mode, either nitrogen or SF o, is made from the digital

control panel. The values of the parameter IANAL are incremented

by 10 to represent SF e mode of operation (Appendix C)

c. All the previous features of the control software have been retained.

Hence, procedures at the operator level remain unaffected.

d. Automatic or manual selection of scaling factors (Appendix C)

e. Appropriate message, whether in the nitrogen or SF e mode,

is displayed on the terminal at various stages of program

execution during testing.

Appendix C gives a summary of the various settings on the digital control panel for the present

version of the software. To facilitate installation and checking the various functions of

the program, a simulation routine has been added. The function of this subroutine is to convert

the pressures measured during operation with nitrogen to equivalent pressures with SF e operation.

This will be helpful in initial checking and can be retained, if necessary, as an additional feature

of the software. Suitable changes are necessary after final validation to retain or delete

this feature.

Val/dJ!!on Tests

The integrated program was successfully installed and wind-off checks were made to ensure the

execution of the software in the modified version. A limited number of wind-on checks were

made to check execution of the flexwall data acquisition and ensure satisfactory execution in the

nitrogen mode. One of the tests involved a complete wall streamlining cycle with a space shuttle

model. Though the two-dimensional streamlining procedure for a three-dimensional model may

not be exact, the test was mainly meant to prove the functioning of the software in the nitrogen

mode. These initial tests have been useful and have saved considerable development work that

would have been required later with the heavy gas. Final wind-on proof tests with the SF e gas

10
will beconductedlaterwhenthe0.3-mTCT is readyfor operationwith SFegas. In thepresent

form, the real gas calculation portion of the software has optional outputs which will be useful in

debugging the program. However, the optional printing may slow down the process and will be

suppressed in the final version.

Appendix E gives a listing of the program used on the HP workstation to calculate the properties

of SFe gas and isentropic expansion. The program can be executed interactively and has provisions for real gas calculations or for using a specified value of the ratio of specific heats. This

option can be installed on the 0.3-m TCT ModComp computer, if found necessary, after final

validation tests.

Acknowledgments

Discussions with Mr. R. V. Jenkins and Mr. J. B. Adcock were helpful in implementing the real

gas program on the 0.3-m TCT computer. Mr. E. Walberg's help in installing and conducting

initial proving tests is gratefully acknowledged.

II
References

l. Ladson,C. L.; and Ray, E.J.: Evolution, Calibration and Operational Characteristics of the

Two-Dimensional Test Section of the Langley 0.3-Meter Transonic Cryogenic Tunnel.

NASA TP 2749, September 1987.

2. Smelt, R: Power Economy in High Speed Wind Tunnels by Choice of Working Fluid and

Temperature. Royal Aircraft Establishment Report No. Aero. 2081, August 1945.

3. Ferri, A.; and 8aronti, P.: A Method for Transonic Wind Tunnel Corrections. AIAA Journal,

Vol. !1, 1973, pp.63-66

4. Sears, W. R.: Self Correcting Wind Tunnels. Aeronautical Journal, Vol. 78, Feb/Mar 1974,

pp. 80-89.

5. Goodyer, M. J.: The Self Streamlining Wind Tunnel. NASA TM-X-72699, August 1975.

6. Everhart, J. E.: A Method for Modifying Two-Dimensional Adaptive Wind Tunnel Walls

Including Analytical and Experimental Verification. NASA TP-2081, February 1983.

7. Murthy, A.V.: An Experimental Study of Wall Adaptation and Interference Assessment Using

Cauchy Integral Formula. AIAA Paper 91-0399, January 1991.

8. Murthy, A. V.: and Ray, E. J.: Experience with some Repeat Tests on the 9-inch Chord

CASTI0-2/DOA-2 Airfoil Model in the Langley 0.3-m TCT Adaptive Wall Test Section. in

"CAST 10-2/DOA-2 Airfoil Studies - Workshop Results", NASA CP 3052, 1989.

9. Wolf, S. W. D.; and Goodyer, M. J: Predictive Wall Adjustment Strategy for Tow-Dimensional

Flexible Walled Adaptive Wind Tunnel. A Detailed Description of the First One-Step

Method. NASA Contractor Report 181635, January 1988.

10.Wolf, Stephen, W.D.: Wall Adjustment Strategy Software for use with the NASA Langley

0.3-Meter Transonic Cryogenic Tunnel Adaptive Wall Test Section. NASA Contractor Report

181694, November i988.

12
I i.Goodyer, M. J.: Computation of Imaginary-Side Pressure Distributions over the Flexible Walls

of the Test Section Insert for the 0.3-m Transonic Cryogenic Tunnel. NASA Contractor

Report 172363, June 1984.

12.'AccuDriSFo", Technical Bulletin/Sulfur Hexafluoride, Fluorine Chemicals Department, Allied

Corporation, TB-524-999-1/87-2M, 1987.

13.Jenkins, R.V.: Program to Calculate the lsentropic Flow Properties of Sulfur Hexafluoride,

SF 8. NASA Technical Memorandum 4358, August 1992.

13
TABLE la

COMPARISONOF SINGLE& DOUBLEPRECISIONCALCULATIONSFORSF6

PROPERTIESONMODCONP-A(STAGNATIONPRESSURE-- 6.0 ATM.)

STAGNATION CONDITIONS

P, NEWTON/M^2 ......................... =

T, TEHPERATURE, g ..................... =

Vo VOLUME W3/KHOLE ................... =

DENSITY, KG/M_3 ....................... =

Z, COMPRESSIBILITY FACTOR ............. ;

CPO, CONS PR IDEAL HEAl CAP. J/KMOLE,K =

L'VO, C_S 'COL IDEAL HEAT CAP. J/KNOLE,K =

CP-CV, J/KMOLE,K ...................... =

CP, CONS PR HEAT CAP. J/KMOLE,K ...... =

CV, CONS VOL HEAT CAP. J/KMOLE,K ...... =

GA/_IA (RATIO CP/CV) ................... =

SOUND SPEED, METERS/SEC ............... =

ISENTROPIC EXPANSION:

P, NEWTON/M'2 ......................... =

T, TEMPERATURE, K ..................... =

V, VOLUME M'3/KHOLE ................... =

DENSITY, KG/M*3 .......................

Z, CO@4PRESSIBILITY FACTOR ............. =

CPO, CONS PR IDEAL HEAT CAP. JIKMOLE,K =

CVO, CONS VOL IDEAL HEAT CAP. J/KNOLE,K =

CP-CV. J//MOLE,K ...................... =

CP, CONS PR HEAT CAP. J/KMO[E,K ...... =

CV, CONS VOL HEAT CAP. J/KMOLE,K ...... =

GAMMA (RATIO CP/CV) ................... =

SOl_D SPEED, HETERS/SFC ............... =

VELOCITY (H/SEC) ...................... =

MACH Nt./bIBER ........................... =

TEST-SECTION MASS FLOtJ (KGS/SEC) ...... =

DYNAMIC PRESSURE (N/M'2) .............. =

REYNOLDS NO./METER .................... =

RATIO PSTATIC/PTOTAL .................. =

RATIO PSTATIC/PTOTAL .................. =

RATIO RHO-STATIC/RHO-TOTAI ............ =

RATIO DYN-PR/PTOTAL ................... =

HODCOMP-A MOOCOHP'A

(REAL*4) (REAL*8)

607000.000000 607000.000000

305.000000 305.000000

3.905272 3.905273

37.399185 37.399183

0.934786 0.934786

98714.062500 98714.029078

90399.718750 90399.689078

11429.773437 11429.783681

104350.812500 104350.787244

92921.031250 92921.003563

1.123005 1.123005

130.293091 130.293218

420000.000000 420000.000000

294.678345 294.678423

5.540188 5.540190

26.362640 26.362633

0.949725 0.949725

96314.781250 96314.822471

88000.43?500 88000.482471

10666.144531 10666.147160

100819.187500 100819,204486

90153.031250 90153.057325

1.118311 1.118312

129.938538 129.938625

108.851898 108.851251

0.837718 0.837713

312.788940 312.787014

156181,937500 156180.082255

0.183099E+09 0.183098E+09

0.691927 0.691928

0,966158 0.966159

0,704899 0.704899

0.257301 0.257298

14
TABI.F, I b

COMPARISON OF SINGLE PRECISIOfl CALCULATIONS FOR Sf6 PROPER1;IES

(STAGNATION PRESSURE = 0.6 AIM.)

MODCOHP-A

(16 bit)

HP-345

(32 Bit)

STAGNATION CONDITIONS

m_.--:: sl ml: _= -_= =aN m_ =_=r.z

P, NEWTON/M'2 ......................... =

T, TEMPERATURE, K ..................... =

V, VOLUME W3/KMOLE ................... =

DENSITY, KG/M^3 ....................... E

Z, COMPRESSIBILITY FACTOR ............. =

CPO, CONS PR IDEAL HEAT CAP. J/KMOLE,K =

CVO, CONS VOL IDEAL HEAT CAP. J/KMOLE,K =

CP-CV, J/KNOLE,K ...................... =

CP, CONS PR HEAT CAP. J/KMOLE,K ...... =

CV, CONS VOL HEAT CAP. J/KNOLE,K ...... =

GANNA (RATIO CP/CV) ................... =

SOUND SPEED, METERS/SEC ............... =

60700.000000

305.000000

41.517105

3.517923

0.993775

98714.062500

90399.71875O

8569.808594

99208.93_00

9_39.125000

1.094549

136.995361

60700.000000

305.000000

41.517113

3.517923

0.993775

98714.039000

90399.703000

8569.610500

99208.937000

90639.125000

1.094549

136.995460

ISENTROPIC EXPANSION:

P, NEgTON/M'2 ......................... =

T, TEMPERATURE, K ..................... =

V, VOLUME W3/KMOLE ................... =

DENSITY. KG/M*3 ....................... =

Z, COMPRESSIBILITY FACTOR ............. =

CPO, CONS PR IDEAL flEA[ CAP. J/KMOLE,K =

CVO, CONS VOL IDEAl. HEAT CAP. J/KMOLE,K =

CP-CV, J/KMOLE,K ...................... =

CP, CONS PR HEAl CAP. J/KM_[E,K ...... =

CV, CONS VOL HEAl CAP. J/KMOLE,K ......

GAMMA (RATIO CP/CV) ................... =

SOUND SPEED, METERS/SEC ...............

35000.000000

290.833618

68.796326

2.122991

0.995774

95394.500000

87080.156250

8491.566406

95758.843750

87267.281250

1.097305

134.214905

35000.000000

290.833670

68.796341

2.122991

0.995?74

95394,546000

87080.203000

8491.565400

95758.906000

87267.343000

1,09_05

134.214980

VELOCITY (M/SEC) ....................... 136.300598

MACH NUMBER ............................ 1.015540

TEST'SECTION MASS FLO_ (KGS/SEC) ...... = 31.540771

DYNAMIC PRESSURE (N/M'2) ............... = 19720.304687

REYNOLDS NO./METER .................... = 0.187199E+08

RATIO PSTATIC/PTOTAL .................. = 0.576606

RATIO PSTATIC/PTOTAL .................. = 0.953553

RATIO RHO'STATIC/RHO TOTAL ............ = 0.603478

RATIO DYN-PR/PTOTAI .................... = 0.324881

136.300330

1.015538

31.540716

19720.232000

0.187199E+08

0.576606

0.953553

0,603478

0.324880

i5
TABLE lc

COMPARISON OF SINGLE PRECISION CALCULATIONS FOR SF6 PROPERTIES

(STAGNATION PRESSURE = 6.0 ATM.)

STAGNATION CONDITIONS

= === Iz_W=l_sW_t=l zlR=_

HCOCONP-A

(16 Bit)

HP-345

(32 Bit)

P, NE_/TON/M'2 ......................... =

T, TEMPERATURE, K ..................... =

V, VOLUME M'3/ICHOLE ................... =

DENSITY, KG/MA3 ....................... =

Z, COMPRESSIBILITY FACTOR ............. =

CPO, CONS PR IDEAL HEAT CAP. J/IO4OLE,K =

CVO, CONS VOL IDEAL HEAT CAP. J/IGMOLE,K =

CP- CV, J/KNOLE, K ...................... =

CP, CONS PR HEAT CAP. J/KMOLE,K ...... =

CV, CONS VOL HEAT CAP. J/KMOLE,K ...... =

GAMMA (RATIO CP/CV) ................... =

SOUND SPEED, METERS/SEC ............... =

607000.000000

305.000000

3.905272

37.399185

0.934786

98714.062500

90399.718750

11429.773437

104350.812500

92921.031250

1. 123005

130. 293091

607000. OOOOOO

305.000000

3.905273

37.399176

0.934787

98714.039000

90399.703000

11429.782000

104350.790000

92921.015000

I.123005

130.293220

ISEN[ROPIC EXPANSION:

p, NEWTONIM^2 ......................... = 420000.000000

T, TEMPERATURE, K ..................... = 294.678345

V, VOLUME M_3/KMOLE .................... 5.540188

DENSITY, KG/M_3 ....................... = 26.362640

Z, CONPRESSIBILllY FACTOR ............. = 0.949725

CPO, CONS PR IDEAL HEAT CAP. J/KMOLE,K = 96314.781250

CVO, CONS VOL IDEAL HEAT CAP. J/KMOLE,K = 88000.437500

CP-CV, J/KMOLE,K ....................... 10666.144531

CP, CONS PR HEAT CAP. J/KMOLE,K ...... = 100819.187500

CV, CONS VOL HEAT CAP. J/KMOLE,K ...... = 90153.031250

GAMMA (RATIO CP/CV) ................... = 1.118311

SOUND SPEED, METERS/SEC ............... = 129.938538

VELOCITY (M/SEC) . ..................... = 108.851898

MACN NUMBER ....................... = 0.837718

TEST SECTION MASSFLOU (KGSISEC) ...... = 312.788940

DYNAMIC PRESSURE (N/M'2) .............. = 156181.937500

420000.000000

294.678300

5.540190

26.362633

O .949725

96314,820000

88000.484000

10666.148000

100819.210000

90153.062000

1.118312

129.938610

108.851430

0.837714

312.787500

156180.590000

REYNOLDS NO./METER .............. •...... O. 18"30_9_+09 O. 18309_+09

RATIO PSTATIC/PTOIAL ................... 0.691927 0.691927

RATIO PSTATI C/PTOTAL ................... 0.966158 0.966159

RATIO RHO"STAT IC/RHO TOTAL ............ = 0.704899 0.704899

RATIO DYN" PR/PTOTAL .................... 0.257"301 0.257299

16
0

0>

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17
(compUted)

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A_
Sources

Sinks _'_._

@ e e e "_...

_. _-:--._--.....__

MODEL

Fig. 3: Distribution of Sources and Sinks in IFLEX Method.

19
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25
APPENDIX A

Preliminary Check-Out of the 0.3-m TCT Adaptive Wall System

The purpose of this check-out program was to ensure that the 0.3-m TCT adaptive wall system

is functioning satisfactorily before the changes for sulfur hexafluoride operation can be implemented. This effort was necessary in view of the several changes to both the tunnel hardware

and software systems in the last two years, initial operation by the 0.3-m TCT staff on a checkout model proved unsuccessful in obtaining a successful operation of the adaptive walls and convergence of wall shapes. Following this efforl, the check-out program was initiated using the

13-inch chord NACA 0012 airfoil model.

The check-out program consisted of the following:

a) Primary measurements

Tunnel total pressure

Tunnel static pressure

Tunnel reference pressures

Adaptive wall hardware:

Wall alignment, i.VDT calibrations

Wall pressure measurements and instrumentation

c) Control software

The check-outs for items a-b, and rectifying the observed problems, greatly helped the adaptive

walls to perform in a predictable manner. Most of the problems were not of a type as to cause

adverse effects on the wall adaptation process. However, they needed rectification in order to

achieve the desired test accuracy and trouble free wall movements in a production testing environment. One of the major source of errors which affected blockage corrections was a leakage

in the total pressure measurement tubing. The wall pressure measurements were also checked

using both tunnel static and vacuum as reference pressures.

After these changes, it was noted that the walls moved correctly in the first iteration, but never

seemed to converge in subsequen! iterations. The solutions for wall shapes showed continuous

driving of the wails towards free jet conditions. It was difficult to attribute this behavior to any

known past trends or experience. No obvious errors or doubts about measurement systems were

present at this stage.

26
Moredetailed off-line checks _1" the wall adjuslment software on a tIP workstation showed that

the wall shape soluti_ns wele satisfactory and the inlerfelence levels low enough to be acceptable.

This enigma was resolved by tracing the cause of the error to a limitation of the new operating

system recently installed on the ModComp computer in the 0.3-m TCT. The new system interpreted multiplication of an integer constant and a real variable differently in the subroutine

IFLEX which calculates new wall shapes for each iteration. This limitation resulted in calculation of wall movements in only one direction by ignoring the sign of the real variable. The same

subroutine had worked satisfactorily under the old operating system. This spurious calculation

resulted in unidirectional movement of the walls, increasing the level of residual interference

with additional iterations showing no sign of convergence of wall shapes.

This limitation was overcome by defining the integer const:lnt as a real number in the 1FLEX

subroutine. With this change, the adaptive wall software worked satisfactorily. The successful

operation was demonstrated on a 13-inch chord NACA-0012 airfoil model at two angles of attack. Following this, another airfoil model has been tested successfully by the 0.3-m TCT staff

over a range of Mach numbers and angles of attack. The observed limitation of the new operating system requires caution in developing new programs until the system is modified.

Improvements to software

l)uring the course of the check-out program, a new procedure for setting the scaling factors for

top and bottom walls was suggested. The new procedure provides a choice for choosing scaling

factors either automatically or manually through the digital constants panel. This change

eliminates the need for maintaining different programs for these tasks. Often, while testing under hard to adapt conditions, it is desirable to use the manual feature to set lower values of the

scaling parameters to improve convergence. Mr. Eric Walberg implemented the new procedure

in the adaptive wall software.

27
APPENI)IX B

lsentropic Expansion of Sulfur Hexafluoride (SF6)

The equation of state and the Ideal constant-pressure heat capacity for SF 6 are given by 12'Is

RT

(v - b)

i=5

E ai + hiT + c i e._l:(-kT/'r e)

(V - h) _

i=2

t

(,po = Ao + AIT +_A2 '1"2 + A3 T'_ 4 ,44T-2

BI

B2

The various constants equations A I and A2 are given by

h = 0.047812001

k = 6.8830220

T = 318.8

¢

a 2 = - 1.064506759 x 106

a s = 1.284952625 x 10 u

a 4 = - 7.338851897 x l0 s

a 5 = - 3.25590376

h_ = 1.170089157 x l0 s

h 3 _ - 1.040549130 x 102

t, 4 = 0.0

h_ = 7.271143381 x 10 n

c 2 = - 5.007990044 x 10 r

c s = 8.783983640 x 10°

c 4 = 0.0

% = 2.048535876 x 104

A = 15748.49323

O

A 1 = 575.7699892

A_ = - 0.749044588

A 3 = 3.538653215 x 10 -4

A 4 = - i,402388775 x 108

For given values (5 pressure and teml_eralure, the equation of stale is soh, ed to calculate the

vohnme V. 'Fhe constant pressure ideal heat capacity depends only on the temperature. The

¢,art:Slmnding constant-volume ideal heat capacity C _' is given by "V

C " = C o _ R B3

v p

28
where R is the universal gas constant.

The corresponding expressions for the heat capacities, Cp and Cv for the non-ideal behavior of

the gas are given by

Cp Cv = -T (0P/aT)_'/(aP/cgV) B4

Cv = Cv° + T (cg_P/OT2)vdV B5

For the real gas expansion from stagnation conditions at temperature Tt and volume Vt, to conditions at temperature T 1 and volume V 1, the change in enthalpy (H) and entropy (S) are given by

rTt o ['Vt Vt ..:_,)_H,T:_) -j_o.T-j:_- RT.V,)_,,_ .T:,_T_,Io::T,,V _)_Vt

+Iv_P1 - RTI/V1) dVl " Tl(cg/0T1) Ivl(P1-RT1/V1) dVl

oo

+ (PtVt- RTt) + (P1V1 - RT1)

S('rt,Vt) - S(T1,V1) - R log(Tt/Vt)

Vt

+ (O/OTt)foo(Pt-RTt/V t) dV t

B6

R log(Tl/V1) + (0/0Tlf vl - (P1-RTJV1) dV 1

oo

B7

The equations A6 and A7 are derived using the departure function technique defined by the difference in gas properties between the real and ideal states. For the particular case of isentropic

expansion, the change in entropy between the initial and final conditions is zero. The temperature after isentropic expansion is determined by solving equations for state, heat capacity and the

entropy. Because of the transcendental nature, the equations are solved iteratively. Knowing

the change in enthalpy, the fluid velocity U after isentropic expansion is calculated from,

U = ! 2 {H(Tt,Vt) - It(TI,VI)}/W! 1/2 B8

where W is the molecular weight.

29
APPENDIX C

DIGITAL CONTROl, PANEL SETTINGS

Parameter Sym bol N 2 SF e Remarks

Analysis IANAL 0 10

I 11

2 12

3 13

Airfoil Tests

Empty TS Streamlining

Re-analysis (Airfoil Tests)

Development Streamlining

Scaling

Factor

TWSF &

BWSF

0.0

>0.0

0.0

>0.0

Automatic Scaling

Iteration -1 0.80

Iteration --2 0.70

Iteration>:,3 0.60

Set Values

For all lterations>=l

Coupling

Factor

TWCPLF

BWCPIJF

0.35 0.35 Recommended Value

(Do not change)

30
APPENDIX D

SUMMARY OF ADAPTIVE WALL SOFTWARE MODIFICATIONS

Name Status Changes Remarks

FLXWAS* E Yes Statements & calls related

to IANAL parameter

INITWA + E No

STWALL E No

WALCAL + E No

STAR + E No

WALDAT E Yes

WAS E Yes

SUME E Yes

OUT E Yes

IFLEX E,M No

ERROR + E No

SMOOTH E No

F1LESORT E No

G ETDATA E No

L IFT E No

BLOCK E No

Statements & calls related

to IANAL parameter

Statements & calls related

to IANAL parameter

Statements & calls related

to IANAL parameter

Statements & calls related

to IANAL parameter

Not documented. Further

Modifications Nov '91.

Sorts array in ascending order

Gets wall data from Ref. Table

OAPCM E No

FLXCOM E No

WASCOM E No

FLXTYP E No

FWPTYP E No

WASTYP E No

FWPEQU E No

FM ASSIGN E No

Common Definition (System)

Common Definition (Flexwall)

Common Definition (WAS)

Type Declaration (Flexwall)

Type Declaration (WASPAR)

Type Declaration (WAS)

Equivalence (WASPAR)

Reference Table

continued.

31
APPENDIX D

SUMMARY OF ADAPTIVE WALL SOFTWARE MODIFICATIONS

i=| ii

Name Status

i i i i i|m

STARSF New

SIMUI., New

SF6 New

SISEN New

SVOL New

SSPHEAT New

SINTCP New

SENRCP New

SRCONS New

Changes Remarks

Boundary-layer calculation

for SF 6 gas

Simulation of SF 6 with N 2.

(For initial checking)

Mach Number, Velocity and

Density Calculation (SFe)

lsentropic Expansion (SF6)

Solves equation of State (SFe)

C, Specific heat at Constant

P_'essure Calculation. (SF6)

Calculates Integral of C from

Temperature T 1 to T t (S_e)

Integral for Entropy change

calculation (SFe)

Calculation of constants (SFe).

* Main Program; E: Existing; M: Modified

+ I/0 changes only to compile on HP-Workstation.

Concluded.

Note: in addition to the programs listed in the table, the adaptive wall software

contains/uses several other system calls and procedures for dedicated tasks.

32
C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

APPENDIX E

PROGRAM FOR CALCULATING SF s PROPERTIES

PROGRAM MAIN

IMPLICIT REAL*8 (A-H,O-Z)

DIMENSION PSTAT(22),EM(22),DENS(22),VELFPS(22),IERR(22)

LO=6

PRINT * 'ENTER TOTAL PRESSURE IN PSIA; '

READ * PTOTAL

PRINT * 'ENTER TEMP IN K ; '

READ * TTOTAL

PRINT * 'NUMBER OF STATIC PRESSURES;'

READ * NPORTS

PRINT * 'ENTER STATIC PRESSURE IN PSIA; '

PRINT * 'INPUT NEGATIVE VALUE TO CALCULATE FOR STAG ONLY); '

DO i00 I=I,NPORTS

PRINT * I

READ * PSTAT(I)

i00 CONTINUE

PRINT * 'ENTER PRINT PARAMETER, 0,1 OR 2; '

READ * IPRN

PRINT * 'ENTER TYPE OF CALCULATION;'

PRINT * '0 FOR REAL GAS CALCULATIONS'

PRINT * 'I FOR IDEAL _AS(GAMM STAG VALUE)'

PRINT * '2 FOR IDEAL GAS(SPECIFIED GAMMA VALUE)'

READ * ICODE

rF(ICODE.EQ.2) READ *,SPGAMA

CALL SF6(PTOTAL,TTOTAL,NPORTS, PSTAT, ICODE, IPRN,

+SPGAMA, EM, DENS,VELFPS, IERR)

PRINT *, EM, DENS,VELFPS

DO 200 I=I,NPORTS

WRITE(LO, 150) I,PSTAT(I),EM(I),DENS(I),VELFPS(I)

150 FORMAT(5X, I2,4FI5.6)

200 CONTINUE

STOP

END

SUBROUTINE SF6(PTOTAL, TTOTAL,NPORTS, PSTAT, ICODE, IPRN,

+SPGAMA, EM, DENS,VELFPS, IERR)

IMPLICIT REAL*8 (A-H,O-Z)

DIMENSION PSTAT(22),EM(22),DENS(22),VELFPS(22),IERR(22)

PURPOSE:

TO CALCULATE LOCAL MACH NUMBERS, DENSITY AND VELOCITIES

AT WALL MEASUREMENT POINTS AS_:UMING ISENTROPIC EXPANSION.

METHOD:

TWO OPTIONS ARE AVAILABLE. A) REAL GAS CALCULATIONS FOR

EACH PORT. B) ISENTROPICEXPANSION BASED ON GAMMA VALUE

FOR STAGNATION CONDITIONS PERFORMED.

INPUT PARAMETERS:

PTOTAL : TOTAL PRESSURE _ (PSIA)

TTOTAL : TOTAL TEMP (K)

NPORTS : NUMBER OF PORTS FOR CALCULATION

PSTAT(NPORTS) : STATIC PRESSURE (PSIA) NPORTS TIMES

: INPUT -VE VALUE FOR STAGNATION CALC ONLY

33
=

±

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

c

C

C

C

ICODE

IPRN

CALCULATION CODE

=0 REAL GAS CALCULATIONS

=i EXPANSION BASED ON STAGNATION GAMMA

=2 EXPANSION BASED ON SPECIFIED GAMMA

PRINT PARAMETER

=0, NO PRINT OUTOUT

=I, OUTPUT FINAL PARAMETERS(ICODE=0)

=2, LONG OUTPUT (FOR CHECK) (ICODE=O)

SPGAMA : RATIO OF SPECIFIC HEATS (ONLY FOR ICODE=2)

RETURN PARAMETERS:

EM(NPORTS) : LOCAL MACH NUMBERS

DENS(NPORTS) : DENSITY (SLUGS/FT^3)

VELFPS(NPORTS): VELOCITY (FT/SEC)

IERR(NPORTS) : ERROR CODE

=0 NORMAL RETURN

=I PSTATTO0 LOW FOR ISEN CALCULATIONS

/ISENX/ : PROPERTIES AFTER ISEN EXPANSION

/TOTL/ : PROPERTIES FOR STAG. CONDITIONS

C

SUBROUTINES CALLED:

VOL:

RCONS

SPHEAT

ISEN:

VOL:

RCONS

SPHEAT

RCONS

ENRCP

INTCP

COMMON /ISENX/ VEL, F%_ACH,FMASS,DYNPR,REY,

+ PSBYPT, TIBYTT,VTBYVI,DYNBYPT,

+ TI,VI,ZI,GAMI,ASI,DENI

COMMON /TOTL/ ZT,GAMT, A_T, DENT

DATA LO/0LO/

LO=6

DO 400 I=I,NPORTS

IERR(I)=0

PT=6894.7572D+00*PTOTAL

PS=6894.7572D+00*PSTAT(I)

TT=TTOTAL

3O5

IF(IPRN.NE.0) WRITE(LO,305)

FORMAT(/10X,'STAGNATION CONDiTIONS',/10X,' ,)

IF(I.EQ.I) CALL VOL(PT, TT,VT, ZT, GAMT, AST, DENT, IPRN)

PSCHEK=PS/PT

IF(PSCHEK.LT.0.1) GOTO 330

IF(IPRN.NE.0 .AND. ICODE.EQ.0) WRITE(LO,310)

IF(IPRN.NE.0 .AND. ICODE.EQ.I) WRITE(LO,311)

IF(IPRN.NE.0 .AND. ICODE.EQ.2) WRITE(LO,312)

310 FORMAT(/10X,'ISENTROPIC EXPANSION (ICODE=0;

+ ,/10X,' .................

311FORMAT(/10X,'ISENTROPIC EXPANSION (ICODE=I;

. ,/10X,'

GAMT

S PGAMA

REAL GAS) :'

,)

STAG GAMA=' ,F8.4, ' ) '

,---------- .... 0 )

34
C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

312 FORMAT(/10X,'ISENTROPIC EXPANSION (ICODE=2; SPEC GAMA=',F8.4,')'

+ ,/10X,' ........... ==============================

315

318

REAL GAS CALCULATIONS FOR EXPANSION

IF(ICODE.EQ.I .OR. ICODE.EQ.2) GO TO 315

IF(ICODE.EQ.0) CALL ISEN(PT, TT, VT, PS,GAMT, IPRN)

GOTO 320

ISENTRPIC EXP BASED ON STAGNATION CONDITIONS

IF(ICODE.EQ.2) GOTO 318

GI=(GAMT-I.0)/2.0

G2=(GAMT-I.0)/GAMT

FMACH=SQRT( ((PT/PS)**(G2) -1.0 )/GI )

G3=I.0/(GAMT-I.0)

G =1.0 + G2*FMACH*FMACH

DENI=DENT/(G**G3)

AS1 =AST /SQRT(G)

VEL =FMACH*ASI

GOTO 320

ISENTROPIC EXPANSION USINF SPECIFIED GAMMA VALUE

GI=(SPGAMA-I.0)/2.0

G2=(SPGAMA-I.O)/SPGAMA

FMACH=SQRT( ((PT/PS)**(G2) -1.0 )/GI )

G3=I.0/(SPGAMA-I.0)

G =i.0 + G2*FMACH*FMACH

DENI=DENT/(G**G_)

AS1 =AST /SQRT(G)

VEL =FMACH*ASI

STORE VALUES

320 EM(I)=FMACH

DENS(I)=DENI/515.379D+00

VELFPS(I) =VEL/0.3048

GOTO 400

330 IERR(1)=I

400 CONTINUE

RETURN

END

SUBROUTINE ISEN(PT, TT, VT, PS,GAMT, IPRINT)

IMPLICIT REAL*8 (A-H,O-Z)

DIMENSION AT(5),DAT(5),DDAT(5),AI(5),DAI(5),DDAI(5)

PURPOSE:

TO CALCULATE ISENTROPIC EXPANSION FOR REAL GAS FROM

GIVEN STAGNATION PRESSURE & TEMPERATURE TO A SPECIFIED

EXPANSION PRESSURE.

ENTRY PARAMETERS:

PT :

'IT:

PS:

VT :

GAMT :

IPRINT :

STAGNATION PRESSURE (N/M^2)

STAGNATION TEMPERATURE_(K )

STATIC PRESSURE AFTER EXPANSION (N/M^2)

STAONATION VOLUME

RATIO Or _PEC_FIC HEATS FOT PT _ VT

OUTPUT PARAMETER

=0 NO OUTPUT TO DISPLAY

=I RESULTS OUTPUT TO DISPLAY

35
C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

C

c

C

C

100

150

RETURN PARAMETERS (IN /ISENX/)

VEL : VELOCITY (M/SEC)

FMACH : MACH NUMBER

FMASS : TEST-SECTIONMASS FLOW (KGS/SEC)

DYNPR : DYNAMIC PRESSURE (N/M^2)

REY : REYNOLDS NO./METER

PSBYPT : RATIO PSTATIC/PTOTAL

TIBYTT : RATIO TSTATIC/TTOTAL

VTBYVI : RATIO RHO-STATIC/RHO-TOTAL

DYNBYPT: RATIO DYN-PR/PTOTAL

T1 : STATIC TEMPERATURE AFTER EXPANSION (K)

Vl : STATIC VOLUME AFTER EXPANSION (N/M^2)

Z1 : COMPRESSIBILITY FACTOR

GAMI : RATIO OF SPECIFIC HEAT AFTER EXPANSION

AS1 : SPEED OF SOUND FOR STATIC CONDITIONS (M/SEC)

DEN1 : DENSITY (KG/M^3)

SUBROUTINES CALLED

VOL:

RCONS

SPHEAT

RCONS:

ENRCP:

INTCP:

COMMON /ISENX/ VEL,FMACH,FMASS,DYNPR,REY,

+ PSBYPT, TIBYTT, VTBYVI,DYNBYPT,

+ TI,VI,Zi,GAMI,ASI,DENI

LO=6

CALL RCONS(TT, AT, DAT, DDAT)

XT = I.OD+OO/(VT-O.O4781200ID+O0)

ISENTROPIC EXPANSION

GI=(GAMT-I.0D+00)/GAMT

TI=TT*((PS/PT)**G])

G3=2.0D+00/(GAMT-I.0D+00)

FM=(PT/PS)**GI - 1.0D+00

FMT=DSQRT(G3*FM)

TLO=TI

TUP=0.99999999999D+00*TT

VI=8314.34D+00*TI/PS

IF(IPRINT.EQ.2) PRINT *, TI, V1

CALL ENRCP(TT, TI,_I)

S2 = 8314.34D+00*DLOG((TT*VI)/(VT*TI))

Xl = 1.0D+00/(VI-0.047812001D. 00)

CALL RCONS (TI, AI, DA] ,DDAI)

S3 =

-DAT(1)*DLOG(I.00D+00 + XT*0.04781200iD+00)

+DAI(1)*DLOG(].00D+00 + XI*0.047812001D+00)

+ -(DAT(2)*XT - DAI(2)*XI) _/ i_

+ -(DAT(3)*XT*XT - DAI(3)*XI*Xl)/2.0D+00 :

+ -(DAT(4)*XT*XT*XT - DAI(4)*XI*XI*Xl)/3.0D+00

+ -(DAT(5)*XT*XT*XT*XT - DAI(5)*XI*XI*XI*Xl)/4.0D+00

IF(IPRINT.EQ.2) PRINT *, 'Sl, S2, $3'

IF(IPRINT.EQ.2) PRINT *, SI, $2, $3

G = S1 - $2 + $3 .........

36
C

C

C

C

C

C

C

C

C

C

C

C

C

200

250

3OO

DPV = DAI(5)*(XI**5.0D+00) + DAI(4)*(XI**4.0D+00)

+DAI(3)*(XI**3.0D+00)

+ +DAI(2)*(XI**2.0D+00) _ DAI(1)*(Xl)

DGV = -DPV

IF(IPRINT.EQ.2) PRINT *, DPV, DGV

V2 = V1 - G/DGV

IF(IPRINT.EQ.2) PRINT *, VI,V2

IF (DABS(V2-VI).LT.I.D-II) GOTO 200 change date

IF (DABS(V2-VI).LT.I.D-II .OR. V2.LT.VT) GOTO 200

Vl= V2

GOTO 150

7/13/92

PSI= AI(5)*(XI**5.0D+00) + AI(4)*(XI**4.0D,00)

+ +AI(3)*(XI**3.0D+00)

+ +Ai(2)*(XI**2.0D+00) + AI(1)*(XI)

IF(IPRINT.EQ.2) PRINT *, PSI,PS

ACCURACY CHANGED 7/17/1992 TO 10PASCALS

CONVERGENCE AT LOW PRESSURES

IF(DABS(PSI-PS).LT.0.05D+00) GOTO 300

IF(DABS(PSI-PS).LT.10.0D$00) GOTO 300

TO IMPROVE

IF((PS-PSI).LT.0.0) GO

TLO=TI

T1 = (TLO+TUP)/2.0D+00

GOTO i00

TUP=TI

T1 = (TLO+TUP)/2.0D+00

GOTO 100

CONTINUE

TO 250

CALL VOL(PS,TI,VI,ZI,GAMI,ASI,DENI,IPRINT)

ENTHALPY CALCULATION "

CALL INTCP(TT, TI,SI)

S2 = -AT(1)*DLOG(I.00D+00 + XT*0.047812001D+00)

÷ -AT(2)*XT

÷ -AT(3)*XT*XT/2.0D÷00

+ -AT(4)*XT*XT*XT/3.0D+00

+ -AT(5)*XT*XT*XT*XT/4.0D+00

PRINT *, SI, $2

S3 = °AI(1)*DLOG(I.00D+00 ÷ XI*0.047812001D+00)

+ -AI(2)*Xl

+ -AI(3)*XI*XI/2.0D+00

+ -AI(4)*XI*XI*XI/3.0D+00

+ -AI(5)*Xl*Xl*XI*XI/4.0D+00

PRINT * # $3

S4

÷

+

+

+

S4

PRINT * $4 i

= -DAT(1)*DLOG(I.00D+00 + XT*0.047812001D+00)

-DAT(2)*XT

-DAT(3)*XT*XT/2.0D+00 .....

-DAT(4)*XT*XT*XT/3.0D+00

-DAT(5)*XT*XT*XT*XT/4.0D+00

= TT*S4

= -DAI(1)*DLOG(I.00D+00 + XI*0.047812001D+00)

-DAI(2)*XI

-DAI(3)*XI*XI/2.0D_00

-DAI(4)*XI*XI*XI/3.0D+00

-DAI(5)*XI*XI*XI*XI/4.0D÷00

= TI*S5

$5

_5

+

+

+

S5

PRINT *,

37
C

C

S6 = PT*VT - PS*VI + 8314.34D÷00*(TI -TT)

PRINT *, $6

DH = Sl - S2 + $3 + S4 - $5 + $6

IF(IPRINT.EQ.2) PRINT *, DH

VEL= DSQRT(2.0D+00*DH/146.054D*00)

GI=(GAMI-I.0D+00)/GAMI

G3=2.0D+00/(GAMI-I.0D+00)

FM=(PT/PS)**GI - 1.0D+00

FMI=DSQRT(G]*FM)

FMACH= VEL/ASI

FMASS=VEL*DENI*0.1090D+00

DYNPR=0.5D+00*DENI*VEL*VEL

REY =DENI*VEL/(TI*5.59D-08 - 8.0D-07)

PSBYPT=PS/PT

TIBYTT=TI/TT

VTBYVI=VT/VI

DYNBYPT=DYNPR/PT

IF(IPRINT.EQ.I .OR. IPRINT.EQ.2) WRITE(LO,310)

+VEL, FMACH, FMASS,DENI,DYNPR,REY,PSBYPT, TIBYTT, VTBYVI,DYNBYPT

310 FORMAT(/10X,'VELOCITY (M/_EC) ....................... ' F20.6,

+ /10X,'MACH NUMBER ........................... ' F20.6,

+ /10X,'TEST-SECTION MASS FLOW (KGS/SEC) ....... ' F20.6,

+ /10X,'DENSITY, KG/M^3 ........................ ' F20.6,

+ /10X,'DYNAMIC PRESSURE (N/M^2) ............... ' F20.6,

+ /10X,'REYNOLDS NO./METER ..................... ' E20.6,

+ /10X,'RATIO PSTATIC/PTOTAL ................... ' F20.6,

÷ /10X,'RATIO TSTATIC/TTOTAL ................... ' F20.6,

÷ /10X,'RATIO RHO-STATIC/RHO-TOTAL ............ =' F20.6,

+ /10X,'RATIO DYN-PR/PTOTAL .................... ',F20.6)

IF(IPRINT.EQ.2) PRINT *, 'SI,S2,S3,S4,S5,S6,DH/146.054D+00'

IF(IPRINT.EQ.2) PRINT *, SI,S2,S3,S4,SS,S6,DH/146.054D+00

IF(IPRINT.EQ.2) PRINT *, 'VEL, FMACH, FMT, FMI'

IF(IPRINT.EQ.2) PRINT *, VEL, FMACH,FMT, FMI

RETURN

END

SUBROUTINE VOL(P,T,V,Z,GAM, AS,DEN, IPRINT)

P: IN PASCALS(N/M**2); T: IN KELVIN; V: M**3/KMOLE (OUTPUT)

IMPLICIT REAL*8 (A-H,O-Z)

DIMENSION A(5),DA(5),DDA(5)

LO=6

CALL RCONS(T,A, DA, DDA)

X = P/(8314.34D+00*T)

I00 F = A(5)*(X**5.0D+00) + A(4)*(X**4.0D+00) + A(3)*(X**3.0D+00)

+ +A(2)*(X**2.0D+00) + A(1)*(X) - P

FD= 5.0D+00*A(5)*(X**4.0D+00) + 4.0D+00*A(4)*(X**3.0D+00)

+ +3.0D÷00*A(3)*(X**2.0D+00) + 2.0D+00*A(2)*X + A(1)

XI= X - F/FD

IF (DABS(Xl-X).LE. 1.0D-10) GOTO 200

X = X1

GOTO 100

200 CONTINUE

CALCULATE VOLUME & COMPRESSIBILITY FACTOR

V = 0.047812001D+00 + (I.0D+00/X)

Z = (P*V)/(8314.34D+00 *T)

CALCULATE CP-CV

DPV = -5.0D+00*A(5)*(X**6.0D+00) - 4.0D+00*A(4)*(X**5.0D+00)

+ -3.0D+00*A(3)*(X**4.0D+00)

+ -2.0D.00*A(2)*(X**3.0D+00) - A(1)*(X**2.0D+00)

38
C

C

C

C

C

C

DPT = DA(5)*(X**5.0D+00) + DA(4)*(X**4.0D+00)

+ +DA(3)*(X**3.0D+00)

+ +DA(2)*(X**2.0D+00) + DA(1)*(X)

CPMCV= -T*(DPT*DPT)/DPV

DINT IS INTEGRAL OF DDPDTT W.R.T V

DINT = -(DDA(5)/4.0D+00)*(X**4.0D*00)

÷ -(DDA(3)/2.0D+00)*(X**2.0D+00)

+ -(DDA(2)/I.0D+00)*(X)

CALL SPHEAT(T, CP0)

CV0 = CP0 - 8314.34D+00

CV = CV0 + T*DINT

IF(IPRINT.EQ.2) PRINT *, CP0,CV0

GAM = 1.0D+00 + (CPMCV/CV)

CP = CPMCV + CV

SPEED OF SOUND

AS = DSQRT(-GAM*V*V*DPV/146.054D+00)

DEN = 146.054D+00/V

IF(IPRINT.EQ.I .OR. IPRINT.EQ.2) WRITE(LO,300)

+P,T,V, DEN, Z,CP0,CV0,CPMCV, CP,CV,GAM, AS

300 FORMAT( 10X,'P, NEWTON/M^2 ......................... =',F20.6

+

+

+

+

+

+

+

+

+

+

÷

RETURN

/10X,'T, TEMPERATURE, K ..................... =',F20.6

/10X,'V, VOLUME M^3/KMOLE ................... =',F20.6

/10X,'DENSITY, KG/M^3 ....................... =',F20.6

/10X,'Z, COMPRESSIBILITY FACTOR ............. =',F20.6

/10X,'CP0, CONS PR IDEAL HEAT CAP. J/KMOLE.K =',F20.6

/10X,'CV0, CONS VOL IDEAL HEAT CAP. J/KMOLE.K = ,F20.6

/10X,'CP-CV, J/KMOLE.K ...................... = ,F20.6

/10X,'CP, CONS PR HEAT CAP. J/KMOLE.K ...... = ,F20.6,

/10X,'CV, CONS VOL HEAT CAP. J/KMOLE.K ...... = ,F20.6,

/10X,'GAMMA (RATIO CP/CV) .................... = ,F20.6,

/10X,'SOUND SPEED, METERS/SEC ................ = ,F20.6)

SUBROUTINE SPHEAT(T,CP)

IMPLICIT REAL*8 (A-H,O-Z)

PURPOSE:

ENTRY :

RETURN :

TO CALCULATE CONSTANT PRESSURE IDEAL HEAT CAPACITY

T, TEMPERATURE (K)

CP, SPECIFIC HEAT J/(KMOLE.K)

CP = -15748.49323D+00 + 575.7699892D+00 * T

+ - 0.749044588D+00 *(T**2.0D+00)

+ + 3.538653215D-04 *(T**3.0D+00)

+ - 1.402388775D+08 *(T**(-2.0D+00))

RETURN

END

SUBROUTINE INTCP (TT, TI, $I )

IMPLICIT REAL*8 (A-H,O-Z)

S1 = -15748.49323D+00*(TT-TI)

+ +575.7699892D+00" (TT*TT-TI*TI)/2.0D+00

+ -0.749044588D+00" (TT*TT*TT-TI*TI*TI)/3 .0D+00

+ + 3 .53865_215D-04" (TT*TT*TT*TT-TI*TI*TI*TI)/4.0D+00

+ -I.402388775D+08*(-I.0D+00/TT +I.0D+00/TI)

RETURN

END

39
C

C

C

C

S1 = -

+ +

+

+ +

+ +

+

PRINT *, _Vl',

RETURN

END

SUBROUTINE ENRCP(TT, TI,SI)

IMPLICIT REAL*8 (A-H,O-Z)

15748.49323D+00*DLOG(TT/TI)

575.7699892D+00*(TT -TI)

0.749044588D+00*(TT*TT -TI*TI)/2.0D+00

3.538653215D-04*(TT*TT*TT -TI*TI*TI)/3.0D+00

1.402388775D+08*(0.SD+00/TT**2.0D+00)

1.402388775D+08*(0.5D+00/TI**2.0D+00)

TI, S1

SUBROUTINE RCONS(T,A, DA, DDA)

IMPLICIT REAL*8 (A-H,O-Z)

DIMENSION A(5),DA(5),DDA(5)

EXPCON=DEXP(-6.8830220D+00*T/318.80D+00)

A(5)=-3.25599376D+00 +7.271143381D-01*T

A(4)=-7.338851897D+03

A(3)= 1.284952625D+05 -I.040549!3D+02 *T

A(2)=-I.064506759D+06 +I.170089157D+03*T

A(1)= 8314.34D+00 *T

-2.048535876D+04*EXPCON

+8.78398364D+06 *EXPCON

-5.067990044D+07*EXPCON

DEXPCO=(-6.8830220D+OO/318.80D+OO)*EXPCON

DA(5) = 7.271143381D-01 2.048535876D+04*DEXPCO

DA(4) = 0.0D+0

DA(3) =-I.04054913D+02 + 8.78398364D+06 *DEXPCO

DA(2) = 1.170089157D+03 5.067990044D+07*DEXPCO

DA(1) = 8314.34D+00

DDEXPC=

DDA( 5 )=

DDA (4 )=

DDA (3 )=

DDA (2) =

DDA (1 )=

RETURN

END

((-6.8830220D+OO/318.80D+OO)**2.0D+OO)*EXPCON

- 2.048535876D+04*DDEXPC

0.0D+0

8.78398364D+06 *DDEXPC

- 5.067990044D+07*DDEXPC

0.0D+00

4O

' REPORT DOCUMENTATION PAGE 1 _ _'. o7o,'_.o,.

_,_,_ ,,d_ ,_ d°,,_. _._9. '_ _ '.'_._'mW'__m_,_,_.__,_ _._ ___.m_._,:.,_,p, ,_?j_L-,.. p___ ._,-_-2: _ ,_ -._,,_-_,_,,_

1. AGrN_Y US| ONLY ('Le,)ve J_arek) | 2. REPORT ()AT| i )- R|POR_ TYPE AND BATES COVERED

J December 1992 [ Contractor Report

4. TITLEAND SUBTITLE 5t FUNDING NUMBERS

hlodiricatlons to Langley 0.3-m TC'T Adaptive Wail Software for C NAS1-18585

lletvy Gas Test Medium - Phase ! Studies

A. V. Murthy

7. P|RFO_MING ORGANIZ/_/rI(_NNAME(S) A_IO AOORESS(ES) =

VIGYAN Incorporated

30 Research Drive

llampton, VA 23666-1325

_" 51;()N$ORING/MONIIORING AGiNCY N&MEIS) AND AOORESS(E5)

National Aeronautics and Space Administration

Langley Research Center

tlnmpton, VA 23665-5225

|1. jUPIM.EMENTARY NOiES ......

WU 505-59-86-02

B. PERFORMING ORGANIZATION

REPORTNUMBER

t0. SPONSONNGI MONITORING

AGENCY REPORTNUMBER

NASA CR- 189"/36

l,angley Technical Monitor: .Ioh, B. Anders, Jr.

' 12;.. blS|RIBUtlON;_VAILABKITY _TA_EMENT

Unclassified- Unlimited

_ubject Category 02

1.t..ABSTRACT (Ma_tmum _ words) '*

12b. DISTRIBUTION CODE

The scheme for two-dimensional wall adaptation with sulfur hexafluorlde (SFe) as test gas in

the NASA Langley Research Center 0.3-m Transonic Cryogenic Tunnel (0.3-m TCT) is

presented. A unified version of the wall adaptation software has been developed to function lit

a dual gas operation mode (Nitrogen or SFB). The feature of Ideal gas calculations for Nitrogen

operation Is retained. For SF e operation, real gas properties have been computed using the

departure fu,lctioo technique. Installation of the software on the 0.3-m TCT ModComp-A

computer and preliminary _'alidatio, with nitrogen operation were found to be satisfactory.

Further validation and Improvements to the software will be undertaken when the 0.3-m TCT is

ready for operation with SF e gas.

_4. _-ubJiCT TERMS

Adaptive wallwind tunnel; Wall ndJnslment strategy

Flexible walled test sections

iT, SEcualrY CLaSSIfICAtION lB. S|CUEI/V CLASSIFKAI'ION

OF REPORT OF THIS PAGI_'

Unclassified Uncla_sifled

15. NUMBER OF PAGES

_6. 'PRICECOOt

A03

SEC_JRII'Y CLASSIFICATION 30. LIMITAI'fON OF ABSTRAI_T

OF ABSTRACT

Stonda_d ICorm_96 (Rev 2-89)

Pl_SCfl4M_ _ ANSI 5ld 1t9.1|

_91.t01