Viewgraphs on non-nuclear materials assessment, nuclear thermal propulsion (NTP) turbomachinery technologies, and high temperature superconducting magnetic bearing technology are presented. The objective of the materials task is to identify and evaluate candidate materials for use in NTP turbomachinery and propellant feed system applications. The objective of the turbomachinery technology task is to develop and validate advanced turbomachinery technologies at the component and turbopump assembly levels. The objective of the high temperature superconductors (HTS) task is to develop and validate advanced technology for HTS passive magnetic/hydrostatic bearing

Swint, Shane

English

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MSFC 
NUCLEAR THERMAL PROPULSION 
TECHNOLOGY PROGRAM 
[ ' /A!4ll9l.'CC / C'3 r \ 
NON-NUCLEAR MATERIALS ASSESSMENT 
TURBOMACHINERY AND PROPELLANT FEED SYSTEM APPLICATIONS." 
"IDENTIFY AND EVALUATE CANDIDATE MATERIALS FOR USE IN NTP 1 I 
THE APPROACH WAS TO DEVELOP AND IMPLEMENT DETAILED TEST PLANS AND EVALUATION 
CRITERIA FOR EFFECTS OF A HOT HYDROGEN ENVIRONMENT ON NTP CANDIDATE MATERIALS. 
THE FOLLOWING MATERIALS WERE SELECTED FOR SURFACE EROSION TESTING: 
- INCONEL 718 (BASELINE MATERIAL) - IMAR 246 - NASA 23 (IMPROVED MARAGING STEEL) (NICKEL BASED STEEL) 
THE FOLLOWING TEST PLANS WERE DEVELOPED: 
- STATIC HOT HYDROGEN TESTING UP TO 1000 C AND 5000 psi. TEST TO INCLUDE: 
TENSILE PROPERTIES 
' LOW CYCLE FATIGUE 
CREEP 
FRACTURE TOUGHNESS 
- FLOWING HOT HYDROGEN TESTING AT TEMPERATURES UP TO 1000 C FOR 
MICROSTRUCTURE CHARACTERIZATION OF EXPOSED MATERIALS 
MATERIAL SAMPLES WERE TESTED AT AUBURN UNIVERSITY IN A 700 C HYDROGEN ENVIRONMENT 
WITH ADDITIONAL TESTS TO BE PERFORMED AT MSFC, ALSO AT 700 C. 
MSFC FACILITY IS CAPABLE OF MATERIAL EXPOSURE TESTING UP TO 980 C AND 5ooopsl IN 
DROGEN OR HELIUM ENVIRONMENT. 
NON-NUCLEAR MATERIALS ASSESSMENT 
The ob/cztlve of the MSFC materials dfort Is l o  ldenllfy and evaluate candidate malarlals lor use In NTP turbonuchlnery and 
propdbnt l e d  ryrtem applkatbns. The lnltlsl task waa to develop r ael of teat plans and evaluatlon crltsrlr that could 
b. spplld to wram orndldrlo matrlslr lor appllcrtlon In NTR componmlr. In order to ba a viable candkhte, the 
malwlal muat be raalstanl l o  degrdallon due lo the elfects of exposure to hydrogen A set 01 bawllne m.terlala -0 
selected whkh Included lnconel718. NASA 23, and IMAR 246. These materiel samplea were provlded lo Auburn 
Unlversny for exposure In a 700 C hydrogen envlronmenl and characlalzallon 01 the Induced surlacce croalon. Slmllar 
hydrogen environment testing wan perlormed a1 MSFC for oblalnlng the mechanlcal popertles 01 the sample. lhrougli 
In situ lestlng In 10 MPA (1500 PSI) hydrogen at 700 C. In situ test capabllilles Include tensile strain properties. lntlgue. 
n e c k  growth, fracture toughness, creep, and four poinl bend. 
NP-TIM-92 N I P :  Technology 476 
https://ntrs.nasa.gov/search.jsp?R=19930017743 2020-03-17T05:26:09+00:00Z
NON-NUCLEAR MATERIALS ASSESSMENT 
HIGH TEMPERATURE TESTING OF VARIOUS CARBIDE BASED COATINGS FOR APPLICATION 
TO TURBOPUMPS, TURBINE BLADES, FLOW SYSTEMS, AND NOZZLES HAVE ARE BEING PERFORMED. 
TaC, WC, & NbC HAVE BEEN EXPOSED TO HYDROGEN AT 1 ATMOSPHERE AND TEMPERATURES OF 
830.1350. & 1460 C TO DETERMINE % WEIGHT LOSS 
% welght loss at temperature 
Material 830 C 1350 C 1460 C 
TaC 0.03 0.03 0.06 
wc 0.07 0.10 0.04 
NbC 0.10 0.36 1.14 
SILICON NITRIDE AND ALUMINA CERAMICS HAVE BEEN TESTED FOR HIGH TEMPERATURE COATING 
APPLICATIONS. COMPARATIVE TESTING WAS PERFORMED IN AIR AND HYDROGEN AT AMBIENT 
TEMPERATURE AND AT 700 C FOR PERIODS OF 1 HOUR. 
A FOUR-POINT BEND FIXTURE WAS USED TO TEST BASIC MECHANICAL PROPERTIES OF MEAN 
STRENGTH AND WEIBULL MODULUS. 
NON-NUCLEAR MATERIALS ASSESSMENT 
High temperature teatlng of carbide b a r d  coallngs for appllcotlon to twbopumps, lurblne blades, flow systems, and 
nozlks are bdng pufornud. Thew coatlngr Include the carblde8 01 Tantalum, Nbblum, Tungsten. and Sllkon. There 
maleriala are bdng expomi lo elevclled temperature8 over the range of 830 C to 1460 C In a vacuum and hydrogen 
environment lor periods of one hour. A ~ l y d ~  consisla 01 In situ welght loss delermlnations and resldual gas analysls 
wlth subsequent axamlnallon 01 mkrostructure vle Scanning Electron Mlcroacopy and Tronsmisdon Electron 
Mlcroocopy. Th. obIoct1vm of thla Inveatlgatlon lo to chsractake microstructural changes In these materlals *a a result 
of exposure to hydrogan. 
Furlher matub1 .valumlona Involve tho proparallon of Slllcon Nltrlde ond Alumina. candidale ceramlcs lor hbh 
temperalure coatlngr. tor comparallve tests In alr and hydrogen at room temperalure and 700 C lor perlode of one 
hour. At MSFC a four polnt bend llxture wan conflgured lo perform in sltu lesllng 01 these materlals for doterminallon 
of lhelr bask mschanlcal properllas of mean slrenglh and Weibull modulus. 
NP-'IIM -92 477 NI'I'. Tcchiiology 
NTP TURBOMACHINERY TECHNOLOGIES 
"DEVELOP AND VALIDATE ADVANCED TURBOMACHINERY TECHNOLOGIES AT THE 
COMPONENT AND TURBOPUMP ASSEMBLY LEVELS." I 
THE NASA REFERENCE SIZE WAS BOUNDED BY 50K AND 75K LB THRUST ENGINE. 
THE APPROACH USED WAS TO ASSESS AND DEFINE TURBOMACHINERY TECHNOLOGY 
REQUIREMENTS FOR A SPACE BASEWSTART NUCLEAR THERMAL ROCKET ENGINE. MSFC 
AND LeRC SPECIALISTS COLLABORATED TO DEFINE AN INITIAL TECHNOLOGY PLAN FOR 
TPA TECHNOLOGY. 
THE PLAN ADDRESSES: 
- BEARINGS (FLUID FILM & FOIL) 
- SLOW START TRANSIENT FOR FLUID FILM BEARINGS 
- RUB TOLERANT MATERIALS FOR FLUID BEARINGS 
- ROLLING ELEMENT CAGE MATERIAL FOR THRUST BEARING (IF REQUIRED) 
- MAGNETIC BEARINGS 
- SEALS 
- DEFINITION OF SEAL REQUIREMENTS 
- RUB TOLERANT MATERIALS 
- EARLY NEED FOR A PROPELLANT FEED SYSTEM TEST BED 
- EARLY DEFINITION OF TRANSIENT LOADS 
- EVALUATION OF FEED SYSTEM IMPACTS ON TURBOMACHINERY 
NTP TURBOMACHINERY TECHNOLOGIES 
The objective of the MSFC turbomachinery technology task Is to develop and validate technologles at the component atid 
turbopump assembly level for appllcatlon In a Nuclear Thermal Rockel engine. Marshall Propulsion Laboratory personnel 
collaborated with turbomachlnery specialists at LeRC on the assessment of the technology requirements and prlorltles as 
well as an lnltlal technology development plan. The ground rules provided that the engine alze be In the range of 50K to 
75K Ib thrust and apace based. Space baaelstart Imposes a need to assess the requirement for low NPSH technologies. 
The technology asseaamen1 and development plan addresses both lluld film and foil bearings. Current thlnklng la that 
rolling element beerlngs would not be used unless In o thrust bearlng application. There exist, to date, llttte experience 
with ehher loll or hydrostatlc bearlnga Most experience addresses only last st0rI translent systems and. therefore. 
Indicate a need for research In the appllcatlon 01 fluid fi ldfoll bearings In a prolonged atart translent such aa tlm NTR 
application. Thla alao Illustrates the need for further materlals research for materiala that would be wear resistant In a 
hydrown and radlatlon environment. The maln concern for rolling element bearlngs Is for appllcatlon as a thrust bearing 
where research is needed to Identify a cage mnterlol tho1 wlll survlve the radlatlon envlronment. The application of a 
megnetlc bearlng could ellmlnate wear at startup nnrl Is olso belng considered. 
Additlonal technology is alao required In the area of seals. Questlons must be addressed as to the need for a positive 
seal between the pump and turblne for pre and post operotion. 
A propellent feed system test bed is needed early In any TPA technology/advanced development program. A prellmlnary 
study has begun to assess the posslblllty of using existing turbomachinery and test stand hardware to lacilltate the 
development of a test stand. The testbed le needed to evaluate translent operation and provide early definition of translent 
loads. This faclllty could also be used to assess ked  system Impacta on the turbomachlnery. The system could also be 
used to evaluate TPA control ond health monltorlng technologles 
NTP: Technology 47 8 NP-TIM-92 
I 
/iu $3 pc; 
HIGH TEMPERATURE SUPERCONDUCTING MAGNETIC 
BEARING TECHNOLOGY 
"DEVELOP AND VALIDATE ADVANCED TECHNOLOGY FOR HIGH TEMPERATURE I SUPERCONDUCTOR (HTS) PASSIVE MAGNETICMYDROSTATIC BEARING" 
GREATLY REDUCE, OR ELIMINATE COMPLETELY, THE EXPECTED WEAR TO A CONVENTlONAL 
HYDROSTATIC BEARING AS A RESULT OF NTR SLOW STARTUP TRANSIENT 
SDIO CONTRACT WITH Mn JOINTLY FUNDED BY DARPA AND NASA 
HTS TECHNOLOGY WILL ENABLE THE DEVELOPMENT OF A NEAR ZERO-WEAR BEARING 
WHEN COMBINED WITH FLUID FILM BEARING CONCEPTS. 
CURRENTLY DESIGNING PROOF-OF-CONCEPT TEST RIG BASED ON MSFC SUPPLIED 
REFERENCE TPA PARAMETERS BASED ON 5-25 TURBOMACHINERY. 
TESTS AND MATERIAL RESEARCH ONGOING TO INCREASE HTS BEARING LOAD CARRYING 
CAPABILITY AT LH2 TEMPERATURES. HTS LOAD CAPABILITY HAS BEEN IMPROVED BY 450%. 
MSFC INHOUSE EFFORTS ARE FOCUSED ON MEASUREMENT OF HTS MAGNETIZATION OVER 
PREDICTED TO BE AROUND 30K. 
TEMPERATURE RANGE FROM 25K TO 77K. NTP-TPA OPERATIONAL TEMPERATURE IS 
HIGH TEMPERATURE SUPERCONDUCTING MAGNETIC 
BEARING TECHNOLOGY 
The o b j a l v e  01 the MSFC HTS technology task Is lo develop ond val1dste advonced technology lor HIM Temperature 
Superconductor ( W E )  passlve nugnetlcYhydroslallc bearlngs lor appllcallon in a nuclear rocket engine. Thls k r l n g  
c m e p l  wlli greatly reduce, of dlmlnate completely. the expected wear to a conventlonal hydrostatic bearlng as a result 
01 Iha extremely slow alartup Iransient 01 the NTR. Thls work was performed by Mechanical Technology Inc. under a 
SDK) conlrscl lunded lolntly between NASAlMSFC and DARPA. 
By comblnlng HTS technology wlth tho1 01 liuld lllm beoringe, It wlll be posslble to auapend the pump shoR durlng the 
start-up and ahut-down of the pump when the hydrostatic bearlng is not lully lundlonal. HTS sllftness has been Improved 
by 450% dulng the course of thl8 eflort and further improvement to capabliltlea of +ZOO0 IMn/lnZ is believed very possiblc. 
MTI WOO supplied relarence parametera based on the J-2s turbopump in order to deslgn s prool-ofconcept lest apparatus. 
Addltloml Inhouse Morte have locused on measurement of HTS magnetization over lemperaturo ranges from 25K 
to 77K. The operational temperature of the turbomachlnery for the NTR Is predicted to be 30K. 
479 NTI' Technology 


MSFC nuclear thermal propulsion technology program

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