NASA T,-chnical Memorandum 86969

Advanced Research and Technology

Programs for Advanced HighPressure Oxygen-Hydrogen

R.,cket "ropulsion

i

S.J. Marsik

Lewis Research Center

| Cleveland, Ohio \ "

and

' S.F. Morea

Marshall Space Flight Center

Huntsville, Alabama

(NASA-TM-E69og) AgVINCP.D _ES|AgC_ AN2 N85-21231

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Preparedforthe

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sponsoredby theJANNAF InteragencyPropulsionCommittee

San Diego,CaliforniAa,pril9-]2,]985

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ADVANCEDRESEARCHAND TECHNOLOGYPROGRAMFOR ADVANCEDHIGH PRESSURE

OXYGEN-HYDROGENROCKET PROPULSION

r

S.J. Marsik

NationalAeronauticsand SpaceAdministration

: Lewis ResearchCenter

Cleveland, Ohio 44135

:. S.F. Morea

NationalAeronauticsand Space Administration

i MarshallSpace Flight Center

Huntsville,Alabama

4 ABSTRACT

A researchand technologyprogram for advancedhigh pressure,oxygen-hydrogenrocketpropulsion

technologyis presentlybeing pursuedby the NationalAeronauticsand SpaceAdministration(NASA)to

establishthe basic disciplinetechnologies,develop tileanalyticaltools and establishthe data

base necessaryfor an orderlyevolutionof the stagedcombustionreusablerocketengine. The need

c. for the programis basedon the premisethat the USA will dependon the Shuttleand its derivative

T I versionsas its principalearth-to-orbittransportationsystem for the next 20 to 30 yr.

N The program is focusedin three principalareasof enhancement: (a) life extension,(b) performanceand (c) operationsand dlagnosis. Within the technologicaldisciplinesthe efforts include:

_ rotordynamics,structuraldynamics,fluid and gas dynamics,materialsfatigue/fracture/life,turbomachineryfluid mechanics,ignition/combustioproce n sses,manufacturing/producibility/nondestructive

evaluationmethods and materialsdevelopment/evaluation.

" i

The paper presentsan overviewof the AdvancedHigh PressureOxygen-HydrogenRocket Propulsion

!i Tsignificant echnologyachieProvement gramSstr.ucture andWorking Groups objectiveswith highlights of several 1

INTRODUCTION

The Space ShuttleMain Engine(SSME) is operationaland has been performingin an excellent

} manner. However,the SSME was designedfor reusabilityand long lifeas well as high performance.

It is in the reusabilityand life areas that technologywork remainsto be done. The design speci- "t

ficationsof the engineare shown in Fig. i.

The high performanceof the engine is attainedby the use of a stagedcombustionpower cycle,

coupledwith high cond)ustlochn amberpressure, Referringto the SSME powerheadcomponents(Fig. 2),

the propellantsare partiallyburnedat a low mixture ratio high pressureand relativelylow temper- :_

ature in the preburnersto producehydrogen-richgas (steam)which powers the high performanceturbo- _)

• pumps. The hydrogen-richgas is then directedto the main injector,where it is injectedalongwlth

L| additionaloxidizerand small amountof fuel, intothe main combustionchamber at high mixture ratio.

The propellantflow, temperaturesand pressuresin varioussectionsof the engineare shown in

"( Fig. 3. Details of the SSMEoperation can be obtained from Ref. 1.

!I The designof the SSME and its hardwarewere basedon the state-of-the-artat the time of its

development. It became evident from the operational experience that the expectations for the initial

hardwarewere too optimistic. Improvementsare needed in all sensitiveareas and sectionsof the

engine to bring its life expectancy to the design requirements. They are also needed to enhance the

engine performance in order to increase operating margins at the upper end of the thrust range and to

improve diagnostics in its operations/maintenance in an effort to re, ca the turnaround time in the

flight schedule. Most of the needed improvements in the SSMEengine require an _mproved technologIcal base. Therefore,NASA instituteda researchand technologyprogramfor advancedhigh pressure,

oxygen-hydrogen rocket propulsion. This paper describes the technology program. It provides a brief description of the program

" swtiruthctuinretheanpdrogelar_bora , bytes suonmmatherizting echnindicaivi l dual effortworbkyeplreovmeidnintsgwisthi pecifi neach c obj diescctiveipslinfeoerndeabchy hdiisghlcipiline ghting several significant achievements within the scope of effort of the program.

• PROGRAMORGANIZATION

Based on the premise that the U.S, will depend on the Shuttle and tts derivative versions Is its

principal _arth°to-Orbit transportation system for the next several decades, NASAinstituted, in

Approved for public release;1 distribution ts unlimited.
1981, a new technology program. The overall objective of the program is to establish the basic discipline technology necessary for an orderly evolution of high pressure, oxygen/hydrogen staged combustion reusable rocket .,ngines in general, and the SSMEin particular. Thus, the work areas within

the program deal with investigation, development and definition necessary to formulate improved

designs and techniques to upgrade performance, extend life, reduce operations cost, lower weight and

improve the functional capability of the main propulsion engines. The program is also directed to

supportthe continueddevelopmentand operationof the space transportationsystemand its derivative

engines. To achievethe objectivethe technologyprogram focuseson three principalareas: (a) Life

ExtensionEnhancement,(b) PerformanceEnhancementand (c) Operations/DiagnosticEnhanceme s nts. The

objectivesof each focus are pursuedwithina seriesof disciplinaryworking groups. The working

group structureis shown in Fig. 4. The responsibilityof each workinggroup is to formulateand

maintaina long-rangeplan for the respectivediscipline,assure its implementation,monitor progress

and initiateactionas necessaryto achievethe objectives. Each working group draws its members

from both the technologyusers who establishneeds and focus priorities,and technologydevelopers

who identifyopportunities.Responsibilityfor the overallaccomplishmentof the program,under

cognizanceof the Propulsion,Power and EnergyDivisionof the Officeof Aeronauticsand SpaceTechnologyhas been assignedto the MarshallSpace Flight Center,Huntsville,Alabama,with the assistance of the Lewis Research Center, Cleveland, Ohio. The overall functional relationship of the

program is shown in Fig. 5.

2

WORKINGGROUPSOBJECTIVESANDHIGHLIGHTSOF SIGNIFICANTACHIEVEMENTS

The technical portion of the technology program is carried out in the working groups as indicated in Fig. 4. The working groups plans comprise some130 Work Elements. These elements are

approximatelyequallydivided betweenthe short-rangedirectionof improvingthe cost per flight

throughcomponentslifeenhancementand providingmodest upratingcapability,and the long-range

directionof performanceimprovementand multipleapplications. Both short-rangeand long-range

elementscan be found in each workinggroup. General objectiveof each workinggroup with a summary

of work elementspursuingthe objectiveare givenbelow. Includedin the descriptionof the Working

Gruupseffortare highllghtsof representativework elementswhich are in variousstagesof progress.

WORKINGGROUPA - BEARINGS

The evolutionof cryogenicturbopumpsto support fully reusablechemicalrocket propulsionhas

placednew demands on bearings. Experiencewith conventionalrollingelementbearings in the SSME _"

turbopumpconfirms previous analytical predictions that the life of this type of bearing will fall _

far short of the reusability goals. While some improvements may come through the use of better _

materials,the major improvementin life requiresuN_thodswhich will reduceeitherbearing speed.Jr _

the bearing load.

The objective of this working group is to advance the state-of-the-art in beartng technology,

prima,lay cryogenic turbomachinery bearing technology, by exploring the life and performance effects

of design changes, design concept changes, materials changes, manufccturtng technique changes and _

) lubrication system changes. I_

Major effort of the working group is focusedon improvedproducibilityof rollingelementbear- _._

! ings through ion plating of materials, surface ion implantation, powder metallurgy techniques, as

well as deve;upment of new design concepts such as magnetic bearings, hydrostatic bearings and hybrtd

1 bearings.

:_ Hybrid Bearings for LH2 and LO? Turbop_s. One of the work elements which promises a large

beneflt Is the developmen_x_r a hyF:n'ldbearing. This bearing consists of a combination of hydrostatic and bail bearings which can be combined to share either speed or load. The two concepts of a

hybrid bearing (i.e., parallel speed and parallel load), can be seen in Ftg. 6, Reduction of either the speed or the load on the ball hearing portion through the transfer of these parameters to the

i hydrostatic PR will dramatically the life in rocket r_ion improve bearing engine turbopump

i appltcatt°ns'¢'J

i WORKINGGROUPB - STRUCTURALDYNAMICS

Oevelol_ent of the current generation of the 02/H2 propulsion systems has been characterized

i by several structural failures, prt_rtly due to htgner cycle fatigue (HCF). A numberof these failures have been solved by trial and error. However, as even higher performance systems are being

planned, better knowledgeof the system dynamic response is required.

The objective of thts working group is to develop improved understanding of the operating

dynamtc characteristics of high-performance ltqutd rocket systems tn order to: increase 11fatima

and performance, decrease weight, identify Incipient failures, meet deflection requtrem_ts, predtct

effect of proposed changes, determine changes to met specified requirements and decrease costs.

l '

i

)
To achieve the objective,the majorityof the effortin this working group is directedtoward

developmentof analyticaltools and methodologythat would allow accuratepredictionof the structural responseand accompanyinglocalstressescaused by complex thermal and mechanicalloads,leadIng to fatigue and failure in space propulsionstructuralcemponents. The goal is to devulop generic

models of the compositeload spectraformed In turbomachlnery,probabillstlcstructuralanalysis

formulationsand _tatistlcalmodels of structures. The models will be based on the SSME environment

and on data from nonreusablerocketengines.

• WORKINGGROUP C - ROTORDYNAMICS

Many SSME turbomachineryfailurescan be attributedto a lack of understandingof the dynamic

behaviorof the rotor and the forcesactingupon it. Rotor instability,high bearing loads and

" operations. excessiverotordeflectionswith rubbing have been some of the problemsencounteredin the early SSME

The objectiveof this working group Is to define the way in which hlgh bearing loads anO rotor

( deflectionsoccur in high pressure,cryogenicturbomachlnery,to describemore accuratelyand com-

! pletelythe forceswhich interactwith the rotorand surroundings,and to define design requirements

for turbomachlnerycoeq_onentwhi s ch influencerotordynamicsloads,deflectionsand stability.

To achieve the objective,a portion of the effort is devoted to the developmentof analytical

! and simulationtechniquesfor betterunderstandingof rotordynamicforcesand their effects on bearIngs,turbine/caseinteractionsand rubbing In turbopumps. Other work elementsin this workinggroup

; pursueinvestigationof: (i) configurationmodificationswhich reducerelativerotor assemblymove-

) mtlenontoanfdwhdynirlampaicrbal ameatncing, ersof (int2)everi rnalfrot ication or friction of dynamcauicscharacteristic ed by pressfitssoafndamp d spllnes ing seal ,ansd, (_I derlva- :)

applicationof eddy currentdampingtechnologyin cryoge;_icturbopumps.

EddyCurrent O_Ing Technology. A uniquemethodof dissipatingvibrationalenergycaused by

i rotor lnstabllltyIs by means of eOOy currentgenerationin a nonferrousconductorcaused to vibrate

in a magneticflux field. Eddy current dampingcan be effectivein controllingboth the synchronous !

and nons)mchronouswhirl,thus reducingdependenceon ultra precisionbalancingor the need for

frequentrebalancing. Furthermore,if properlylocatedand with properlydesignedbearingsupport,

it can reduce the magnitude of forces transmitted through the bearings to the casing, resulting in

bearing ltfe extension. A successful attenuation of synchronous vibration of a stiff unbalanced

i rotor shaft using passive eddy current damping has been demonstrated."

WORKINGGROUPO - TURBOMACHINERY FLUID MECHANICS

i Many SSMEturbomachinery problems can be attributed to designs resulting from lack of understanding of the fluid flow environment in critical areas such as seals, pumpImpellers, turbine

i_ blades, etc.

) The objt ttve of this working group is to advance technology in turbomachinery fluid mechanics . ._ and provide surficient analytical tool for future advanceddesigns. Therefore, the major portion of

the effort is focused on investigation of turbopump characteristics from low blade speed to steady

state conditions. This investigation wtll provide better understanding of transient as well as

steady state modeling. The rest of the effort Is devoted to definingof flute forces on impellers,

i dynamic characteristics of bushing, labyrinth and floating-ring seals and the investigation of

rubbing tolerances.

Compressible Fluid O_namtc Seal Test Facility. At the threshold of major accomplishment tn the

Turbo_hlneryFlulo Mechanics working 6roup ls the establishment of a C_uter-Integrated Compressible Fluid Oyn_tc Seal Test Facility located on the campusof the Texas A&M University. This

! facility ts uniquely equipped to analyze and evaluate seal dynamics (i.e., axial pressure distribution, leakage, direct and cross-coupled stiffness and damping) of existing seals as well as to

predict the dynamics of future designs, thus aiding in optimization of these designs.

Currently the facility ts operational at 8,000 rpm; flow rate of gSOcfm; and 100 pstg pressure

. in air. Four seal configurations (constant clearance, tapered, honeycomb, labyrinth) have been

teste_ and data for seal stiffness, damping and cross-coupling have been obtained. Existing modeling

) appears good for constant clearance seal but is only_rgtnal for tapered seal. Honeycomband

labyrlnthsealmodels requiresignificantmodification. )

) " _KIN6.C_.,.OUPF - FATIGUE@FRACTURE/LIFE

The Space Shuttle Program requires a safe and durable reusable propulsion systmwtth extremely

high performance. Present analytical procedures use_ for life prediction which utilize the flo_

i growth concept, either do not consider conditions required by the SSM_or are too simplistic in their

approach to yield the desired accuracy.
The objectiveof this working group is to improvethe life predictionsof variousfracturecriticalparts by improvingexisting,or developingnew, analyticaltools whichwill be verifiedby

testing,and also to extend life by materialenhancen_nttechniques.

The majorityof the effort in this working group is directedtowardunderstandingand developing

analyticalmodels of low cycle fatigue/highcycle fatigue interactionsand their effectson fracture

mechanism,creep-fatigueconditionsand interactions,environmentalcontributionsto fatigue,and

resultantcumulativefatigue damage. Effort is al_ devoted to the developmentof a methodlor

fatigue life extensionthrough periodicrestoratiom:of a fatigue-damagedsurfaceto its original

condition.

WORKING GROUPG - IGNITION/COMBUSTIONPROCESSES

Developmentexperiencehas indicatedareasof potentialadvancementin combustiondynamic

predictioncodes and experimentalevaluationtechniquesaimed at improvinglife and increasing

operationallimits.

The objectiveof this working group is to extend the state-of-the-artof main combustion

chambers/injectorsand turbinedrive combustorwith emphasison operationaland service 11fe problem

areasexposed duringSSME development. To achieve the objective,the effort of this group is focused

on improvementsand verificationof combustioncodes, enhancementin main chan_)ercombustionand

cooling technology,developmentof analyticaltools for reliablethrust chamber life predictionand

extensionof currentdual throattechnologyto advancedSSME applications, i

Thrust_hamberLife Predictionand Life EnhancedDesign. The main co,_austionchamber (MCC)of

the S_'_'-Ts-'/_postoedan envlronmentthat produceshlgh heat fluxesin the life-limitedthroat

region. To accommodatethese fluxes, the copper base MCC liner is regenerativelycooled through

integralrectangularcoolingchannels. Duringoperation,largetransientthermal gradientssubject

the MCC linerto largethermoplasticcyclic strainswhich in turn influencethe fatigue lifeof the

linerhOt gas wall.

Life predictionsbased on the low cycle thermalfatigue failuremechanismwere generallyunsuccessfulwhen subjected to test verficattons. During hot-fire testing of channel wall combustors at

NASA Lewis ResearchCenter and at Rocketdyne(RockwellInternationalCorp.), it was determinedthat

cyclic operation results in a permanent mid-channel deformation and wall thinning. This thinning ,_:

phenomenonis termed cyclic material creep and appears to be significantly accelerated at elevated _

temperatures. Basedon these results, it was decided that an improved analytical method, which -

models the observed cyclic creep, was needed for life prediction capability. Such a method in which _:

the chamber finite elemen_ geometry is updated periodically to account for accrued wall thinning and _

distortion was developed. _

/

WORKINGGROUPH - FLUID ANDGASDYNAMICS

SSMEdevelopment results point to a lack of data for the gas dynamic environment. Premature

nozzle tube splits, injector tube bending and cracks, bellows shield cracks and face plate cracking ./_

are evidence of this lack of definition.

The objective of this working group is to obtain vlearer understanding of the interaction of the

thermal behavior, flow behavior and material behavior in the hot gas duct systems and thrust chamber

nozzle, for the purpose of finding ways to increase the life and the performance of these systems.

To achieve the objective, the major portion of the effort in this group is devoted to the

develol_nt and verification of analytical medals for reliable predictions in fluid/structural interactions, pressure fluctuations in nonhomogenousflows, multtflutd mixing and turbulence, therml and

chemistry effects in rocket engine subsystems, high and low frequency unsteady |erod_mamtc environ-

,wnts and throe-dimensional viscous flow fteld through turbine stages. A substantial amountof

effort is devoted to understanding the distribution of flow parameters in parallel multtple transfer

ducts under varying upstream and downstream condtttons, and to understanding of the fluctuating pressure field in the discharge of turbines and pumps under varying boundary conditions. Effort is also

devoted to experimental determination of boundary layer behevtoren turbine vanes and blades and the

determination of temperatures and pressures on rotating turbine blades.

Duct Flow Nonuntformtty Study. The hydrogen-rich gas fr_both SSMEturbopumps is routed

through flve hOt-g, transfer duCts into the main injector. Three ducts ere on the fur| side and

two on the oxidizer side. During the steUy state operation of the engine, about 70 percent of the

hot-gas flow is routed through the fuel side and remaining 30 percent is passeO through the oxidizer

side.
It becameapparentearly in the developmentthat the distributionat the exit of the Hot Gas

Manifold(HGM)fuel side duct was nonuniformwith largeflow separationin the lowerhalf of the

centertransferduct and smallerseparationregionsat the innerwalls of the outer transferducts.

: These nonuniformitiesat the exit of the fuel side of the HGM produce localhlgh velocityflow

regionsresultingin high aerodynamicforceson the main injectorliquidoxygen (LOX)posts. Nonunii formitiesin the back pressuresensedby the high-pressurefuel turbineresultedin oscillatoryloads

on the turbine blades.

An evaluationof the fuel-sldeportionof the system, throughanalyticalas well as experimental

effortwas undertakenand directedtoward improvingthe overallflow distributionin the SSME HG-M.

The effortresultedin a proposalto changethe design from the currentthree-ducttransferto a twoduct transferalong with accompanyingmodificationsin the geometryof the system. The three-

' dimensionalviscousflow numericalanalysisshowing a signific_n_i_rovement in flow distribution

in a two-ductsystemwas subsequentlyverifiedexperimentally.u_,

Similareffort was devotedto an evaluationof the fuel turbopumpexhaust and the turnaround

duct (TAD)at the exit of the turbine. The analyticalresults of the flow in the TAD indicatedthree

regionswith potentialseparation. Also the studyof the geometryeffectshas shown that by optlmi_-

ing wall curvatureand flow diffusionin the turnaround,improvedduct performancecan be achieved,o

WORKINGGROUP J - INSTRUMENTATION

The service life and performancerequirementsof the SSME are severelytesting some of the

state-of-the-ardiagn t osticand monitoringequipment.

The objective of the Instrumentation Technology Program is to advance the state-of-the-art of !

instrumentatioass n ociatedwith the SSME to improveservice life and performanceby providing

increasedmeasurementcapabilityand to reduceoperationalcostsby eliminatingunnecessaryinspection and prematurereplacementof components.

There are two broad categoriesof instrumentationbeing investigatedin this program. One category focuses on development of sensors and systems intended to becomean integral part of the engine

duringoperationsand/ormaintenance. The purposeof these instrumentsIs to provide information

necessary for engine control and/oF diagnostics throughout the life of the engine. The other category focuses on instrumentation systems and techniques whose application is primarily intended for

engine componenttest stands and/or the test bed engine, The main purpose of these instruments is

to providerellabledetailed informationfor verificationof analyticalmodels being developedunder I

this technology program. ( *" -;

Research of Pressure Instrumentation. Improved performance of the SSMEengine control and

analysisdependson more reIiabIeand accuratepressuresensing in a wide rangeof temperatures,

pressures and vibration.

The performance and survivability of a solid state (silicon) ptezoreststive pressure transducer

have been successfully demonstrated at liquid nitrogen temperature and at high pressure. The trans- |{_

i dftcucetentr sdesofignecxpansion oncept foarndthemaint SSaiMnEsappl theicati tranonsduce utilirzessealspapckag rimaingrily maintericoalsmprwi esthsion. s|_=llarSuccethesrma sfull coef- _ ._

c_letion ef this effort wtll provide the technology base for the development of space qualified j

advanced pressure transducer hardware for the current Space Shuttle as well as future space vehicles.

Reusable Engine Matntena_e and Instrumentation. The ever-increasing demandsplaced on rocket

engine perfomance and life expoctancy establish the need to develop and incorporate a condition

monitoring system (CHS) into the engtne. Such a system wtli result in significant reductions in

maintenance costs and turnaround times. A large num_r of In-flight and between flight maasuremnts

and analyses wtll be required for a full scale CMS.

It has been established that turbopump rotor bearings and turbine blades are the most critical

elements in limiting turboplmp life. Th_'efore, in the current effort three technologies were

selected to be developed to _o, ltor the bearings one.turbine blades: (a) isotope wear d_toctor, (b)

• fiheroptlc defloctemeter, (c) fiberopttc pyromter. *u In _dttion, design modifications to current I

configuration SSI_ high pres.ure turbopumpsare being developed for incorporationof the sensors. I

Signal processing algorithms were evaluated and ranked for their utility in providing useful t

componenthealth data.

WORKINGGROUPL - MANUFACTURING/PROOUCIBILITY/INSPECTION

The (_Jecttve of this working _roup is to develop _ evaluate manufacturing techniques for ,.

advanced propulsion harchmareand seIacted materials, to c_ttmtze productbilit_ of SS_ ccxq_nts and

asse_ltes a_ to improve production and In-service nondestructive inspection end testtng. [

; s " 2
The work elementsin this group include: vacuum plasmacoating processfor turbopumpcomponents

(i.e.,blades,discs,heat shields,etc.) and combustionchamber walls;advancedwelding techniques

(i.e.,plasmaarc, variablepolarityplasma process,laserwelding, inertiawelding,etc.);evaluation of ceramicmaterialsfor high temperatureL_X/H2 engine components;advancednondestructive

evaluationand inspectiontechniques.

Vacuum Plasma Coatin9 Process. Improvedthermalbarriercoatingsoffer significantpotentialto

increaseservicellfe by reducingleadingedge erosion,protectingthe substratefrom temperature

spiking,minimizingspallingand loweringthe incidenceof radial airfoilcracks. These thermal

barriercoatingsalso offer improvementsin operatingperformanrphy _rovidingprotectionfrom

hydrogenembrittlementor in_rovedthermal resists-caLu elevatedenginetemperatures.

An applicationof a low pressureplasmacoating of a 50150 blendof Cr203 and NiCrAIYon

SSME high pressurefuel turbopumpturbine bladesprovideda significan_,improvementin durabi1_ty

and thermalprotectionwhen testedin a simulatedserviceenvironment.*_

WORKINGGROUP M - MATERIALSDEVELOPMENT/EVALUATION

Historically,rocketenginematerialshave been drawn from a pool of a11oysdevelopedfor use

in air-breathingengines. Years of successfuloperationsusing a disposablerocketenginejustified

such a practice. However,the requirementfor reusabilityand the service life correspondingto the

SpaceShuttle requirementrequiresre-examinationof the selectionof materials. Severalcoat,aresons of operatingcharacteristicsbetweenrepresentativerocket engineand aircraftgas turbine are

shown in Table I.

Since the developmentand evaluationof materialsappears to be the fun;:_entalbuildingblock

in the developmentof advancedengine, the objectiveof this working group is ratherboard; - to

develop and evaluatecandidatem_terialsfor applicationin advancedhigh pressure021H2 propulsion

systems. Therefore,work elementswithin this working group encoe_oass:compatibilityof materials

wlth SSME1ikeenvironmentfor hydrogenembrittlementand ignitionof materialsin oxygenby rubbing

contact,etc.; advancedmaterialsfo, turbopumpco_oonents,i.e.,blades,vanes, turbine disk,

bearings,etc.; evaluationof ceramicsmaterialsfor rocket engine.

BetterMaterialsfor RocketEngineTurbineBlades. A studywas conductedby Rocketdyne

(RockwellInternatlonal)to evaluatesix classesof candidatematerialsfor turbineblaOe llfe

enhancement and/or evolutionary performance enhancement of the SSMEturbopumps. The material classes

evaluatedwere: (a) singlecrystal and advancedsinglecrystal alloys;(b) dir_tlonally solidified

eutectlcsuperalloys;(c) oxide dispersion-strengthenedsuperalloys;(d) rapidsolidification

processedsuperalloys;(el fiber reinforcedsuperalloycomposites;and (f) structuralceramics. The

effort focusedon the three key materialpropertiesindicativeof the operationallifefor an S)E

turbine blade: (1) stress-rupture strength; (Z) mean stress high-cycle fatigue strength; (3) thermal

strain lc_-cycle fatigue strength.

The study identifiedadvancedsinglecrystal alloys,i.e., high thermal gradientdirectionally )

solidifiedor post solidificationhot Isostatlcpressingof conventionallyprocessedsinglecrystal

alloy,as a class of materialswhich would enhance the S_ turbine bladedurabilityby tenfold with

the current turbinedesign (i.e.,retrofit)and currentoperatingconditions. The study also identlfl_ fiber reinforcedsuperalloys(FRS)as a bladema)erialwhich could produce higherengine per- (J"

fomnce by a11owlngthe turbineto operateat a 400 "F increasg_t_erature, while stillproviding )

an )ncreasein durabilityof approximatelytwent_old (Fig.7).*( However,the use of FRS materials )

would requirea modificationin the designof the turbinewheel to acc_ate the blade mounting.

)

Both the advancedsingle crystal and the fiber reinforced superalloys approach are being pursued )

i in the development of new turbine blades, It appears that the advanced single crystal blades could 1

be retrofitted into the curront design of the SSMEturbopu_ in the late 1980's. Blade fabricated

t frooFRS materials could be available for use in the early 19gO's.

) CONCLUDINGREMARKS

The A(lvancad Research and TechnoloEy Programfor Advanced High Pressure Oxygen-Hydrogen Rocket

Propulsion, was instituted by the National Aeronautics and Space Administration, to develop new techi nology which would enable enhancementin both the life and perfomance of the existing system as well

as provide a bests for improved future designs. The program is developing hardware and generic

analytical tools in each disciplinary working group within the program.

i

The follovtng examples are representative of working group efforts:

i (1) Cryogenic hybrid bearings (t.e., cembtnetton of hydrostatic and rolling eles_nts).

(Z) Improvedmethods in rotordynemi¢ balancing and damping in turbemachtnery.

f
(3) Optimization in design of compressible fluid seals (a facilit) fur evaluation of dynamic

: seal characteristicsin now available).

(4) Improvedanalyticaltoolsfor fatlgue/fracture/lifeand structuraldynamicsevaluationand

_, prediction.

(S) Improved analytical tools for aerothermal loads for turbomachlnery, transfer ducts and

fuel injector evaluation and prediction.

: (6) Improved life for main combustion chambers.

7) Improved turbine blades and vanes using thermal barrier coatings.

: 8) Single crystal and advanced single crystal turbine blades for life enhancement.

• (g) Fiber reinforced superalloy rocket engine components for life and performance enhancement.

(lOS Advanced instrumentation, control, health monitoring for e_h.Jncedperformance and improved

economy.

REFERr'.CES

1. Space Transportation System Technical Manual - Space Shuttle Hatn Engine. RSS-85S9-1-1-1,

Rocketdyne Division, Rockwell International Corp., Sept. 1983.

(

; 2. Hannum,N.P.; and Nelson, C.E.: The Performance and Application of High Speed Long Life LH2

Hybrid Bearings for Reusable Rocket Engine Turbomachinery: NASATH-83417, 1983.

3. Butner, M.F.; and Lee, F.C.: Hybrid Bearings for LH2 and LO2 Turbopumps. Proceedings of

MSFCAdvanced High Pressure 02/H2 Technology Conference, S.F. Morea and S.T. ),u, eds., Univ.

of Alabama, 1984, pp. 119-131_ (

4. Cunntngham, Robert E.: Preliminary Results of Passive Eddy Current DamperTechnology for SSME i

Turbomachtnery. Proceedings of MSFCAdvanced High Pressure _2_Z Technology Conference,

S.F. Morea and S.T. gu, ads., Univ. of Alabama, 1984, pp. lgc-zyu.

5. Keeper, Harold J.: Thrust ChandlerLife Prediction. Proceedings of MSFCAdvancedHigh Pressure

02/H2 Technology Conference, S.F. Morea and S.T. Wu, eds., Univ. of Alabama, 1984, pp. 27-30.

6. Pelaccio, O.G.,-et al.: Experimental Evaluation of an AdvancedSpace Shuttle Main Engine Hot-Gas

Manifold Design Concept. Proceedings of NSFCAdvanced High Pressure 02/H2 Technology Conference, S.F. Morea and S.T. Wu, ads., Univ. of Alabama, 1984, pp. 264-28I.

7. Thoenes,J., et al.: NumericalAnalysisof Flow Non-Uniformltyin the Hot Gas Manifoldof the

Space Shuttle Main Engine. Proceedings of MSFCAdvanced High Pressure O2/H2 Technology Con- 1

ference, S.F. Morea and S.T. gu, ads., Univ. of Alabama, 1984, pp. 282-287.

8. McLalltn, Kerry L.: Analytical Study of Flow Phenomenain SSMETurnaround Duct Geometries. I

Proceeding of MSFCAdvancedHigh Pressure O2tH2 Technology Conference, S.F. Morea and

S.T. Wu, eds., Univ. of Alaba,_, 1984, pp. 298_308. t¢

g. Johnson, R.L., and Wamstad, D.B.: An AdvancedSolid State Pressure Transducer for High Relta- _:

btltty SSHEA#plicatton, Proceedings of MSFCAdvancedHigh Pressure 02/H2 Technology Conference, S.F. Morea and S.T. Wu, ads., Univ. of Alabama, 1984, pp. 320:33I.

10. Hmpson, M.E.; and Barkhoudartan, S.: Reusable Rocket Engine TurbopumpCondition Monitoring.

Proceedings of MSFCAdvanced Htgh Pressure O_IH2 Technology Conference, S.F. Morea and

S.T. gu, ads., Univ. of Alabama, 1984, pp. 339-348.

11. Holmes, Richard R.: VacuumPlasma Coatings for Turbine Blades. Proceedings of MSFCAdvanced

High Pressure 021HZ Technology Conference, S.F. Morea end S.T. Wu, ads., Univ. of AlabaeNm,

1984, pp. 4(_,S4.

12. Chandler, W.T.: Materials for AdvancedRocket Engine TurbopumpTurbine BLades. (RIIRD83-207,

Rocketdyne; NASAContrectNAS3-23536.) NASACR-17472g, 1983.
TABLE I. - COMPARISONOF OPERATINGCHARACTERISTICSBETWEEN

ROCKET ENGINE TURBINESAND AIRCRAFT GAS TURBINES

Item Rocket engine Aircraftgas

turbines turbines

Fuel Hydrogenor CH4 Petroleum

distillate

Oxidizer Oxygen Air

Operatingspeed, rpm up to 110 000 15 000

Blade tip speed,ftlsec 1 850 1 850

Horsepowerlblade 700 200 - 470

Turbine inlettemp, R up to 2 160 R (uncooled) 2 600 (uncooled)

Heat transfercoefficient, 54 000 500

Btulft2-hr-F

Thermal spike-transients, up to 30 000 I00

"F/sec

Engine starts 55 - 300 2 400

Operationallife, hrs 7.5 - 100 8000 _

@ L
° SEA LEVEL 375,000 Ib|

• _ VACUUM 470,O00 Ibl

• CHAMIEI PIESSURE 2970 PSIA

n AIIEA RATIO 77 S

r • SPECIFIC IMPULSE (NOM) !

___ • SEA LEVEL 363 2

/ I VACUUM 4552

• MIXTURE IIA'IIO 6 0

I• I

-- _ • LENGTH 167"'

- !

a 1 ,j • DIAMETEI

POWERHEAD 105" x 94 S"

[ , ..,d NOZZLE EXIT 94" ;

• ,,,,.._ • _ •LIFE 7 S HItS

_ 55 ST ',,lIT S

/

'- ISPECIFICATION OIlY WEIGH1 664_i LII

- 0 ......./

0 7.5

L I c-m-3524

#___ FEET

Figurel. - S,oacsehuttle ma_nengine,ma_ndesignspecificahons.

.._ _1,, -_$ ;.'!1;. . "
_

" OFPUOR QUAL{_i
++M++,++,o+_+++++ /++++/++%++Z ;+

+ _ A BEARINGS _( _'_/_/_ '_'_

_5

C.

B STRUC

ROTOR

TURAL

DYNAMICS

DYNAMICS

• MSFCl[iJ WORKING GROUP CO-CHAIRMAN

,- D. IURBOMAC,HINERY FLUIDM, CHANICS • LIRC_ORKING(ROUPCO-CHAIRMAN --

F. FAhGUE:FRACTUREILIFk • DISCIPLINE MEMBERS

• USERMEMBERS/SUBSYStEM MANAGERS -- u-J

_ G. IGNITIONICOIAI_USTIO@PR;OCESSES

+ _

im

H. FLUID& GAS DYNAMICS

-_ X_ ....

_ l _t_NUFACTJRINOIFABRICATION

.... M MAT:BIAL D-VEI+OPM_NTEVALUATION

flcjure4. - Advancedhigh pre$._ure02/H2prOPulsiontKhnology wofklnggroup _tfuctur¢

I NASA HEADQUARTERS

OASI "J OSF

PR OGR,_V_4_AN_,GEMENT

J

WORKING GROUPSJ AS REQUIRED • ,___ II

L_+.,+o+.,+ iI ,,,,,+_,.,,+ii co-c.*m,,_NII iI.,,++C..-,O-.,, C,o.+, ,Am_N ,+,+.,,+l mI i ,,.,,,,°+.+,, _ l ij i ,.., ,ScU+++ PPORT :.. i,

ME.MIUIS I

w_K i

)

IV ............. +. ++ . '.'+,, ,_m+,.+,+ +,+++"+ ,
@

,--BALIS

g_ _op_o,oj, _oo_

20 s

0 1 2 3 4

lIME. sec

\]

"J-HYDROSIATIC

(a)Parallel-speedhybridbearing.

' - HYDROSTAT I HYDROSTATIC

(bP)arallel-loadhybridbearin9.

Figure& - Hybridbearingconcepts.

BENEFITS AVAILABlf

MATERIALS PERFORMANCLEIFE NEAR LONG TERM TERM m

ADVANCED SINGLE _

SUPERALLCOMP OY OSITE

6Or-- F_s g _or MAR _'_

_':L,,n I1 _:"qiHkt

,0

Ill IN

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INHmCF_ENT ]

Figure1.- Ao'vincemdllirlili fo¢rockttengineturbine

IWadescomllredtocurrentlyus_lmatorlilsin SSME-MAR

/VI2_