NASA/TM--2001-209391

Testing of Densified Liquid Hydrogen

Stratification in a Scale Model

Propellant Tank

John M. Jurns

Dynacs Engineering Company, Inc., Brook Park, Ohio

Thomas M. Tomsik

Glenn Research Center, Cleveland, Ohio

William D. Greene

Lockheed Martin Michoud Space Systems, Huntsville, Alabama

September 2001

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NASA/TMm2001-209391

Testing of Densified Liquid Hydrogen

Stratification in a Scale Model

Propellant Tank

John M. Jurns

Dynacs Engineering Company, Inc., Brook Park, Ohio

Thomas M. Tomsik

Glenn Research Center, Cleveland, Ohio

William D. Greene

Lockheed Martin Michoud Space Systems, Huntsville, Alabama

Prepared for the

1999 Cryogenic Engineering and International Cryogenic Materials Conference

sponsored by the Advances in Cryogenic Engineering

Montreal, Quebec, Canada, July 12-16, 1999

National Aeronautics and

Space Administration

Glenn Research Center

September 2001
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Available electronically at http://gltrs.grc.nasa.gov/GLTRS ...............
TESTING OF DENSIFIED LIQU_ HYDROGEN STRATIFICATION

IN A SCALE MODEL PROPELLANT TANK

John M. Jums

Dynacs Engineering Company, Inc.

Brook Park, Ohio

Thomas M. Tomsik

National Aeronautics and Space Administration

Glenn Research Center

Cleveland, Ohio

William D. Greene

Lockheed Martin Michoud Space Systems

Huntsville Operations

Huntsville, Alabama

SUMMARY

This paper describes a test program that was conducted at NASA to demonstrate the ability to load densified

LH 2 into a subscale propellant tank. This work was done through a collaborative effort between NASA Glenn

Research Center and the Lockheed Martin Michoud Space Systems (LMMSS). The Multilobe tank, which was made

from composite materials similar to that to be used on X-33, was formed from two lobes with a center septum. Test

results are shown for data that was collected on filling the subscale tank with densified liquid hydrogen (DLH 2) propellant that was produced at the NASA Plum Brook Station. Data is compared to analytical predictions. Data collected for this test series agrees well with analytical predictions of the environmental heat leak into the tank and the

thermal stratification characteristics of the hydrogen propellant in the tank as it was filled with DLH 2.

INTRODUCTION

NASA has identified propellant densification as a critical technology in the development of the single stage to

orbit (SSTO) reusable launch vehicle (RLV) designated by Lockheed Martin as the VentureStar TM. The densification of cryogenic propellant through subcooling allows 8 to 10 percent more propellant to be stored in a given volume. This allows for higher propellant mass fractions than would otherwise be possible with conventional, normal

boiling point cryogenic fluids.

To date, several aspects of densification technology have been investigated. Previous tests at NASA have been

conducted with a subscale liquid hydrogen densifier (ref. 1). This test hardware was built and tested to prove the

ability to produce DLH 2 at 2 lbrrdsec. The next step after production of densified LH 2 was to investigate the particulars of performing the sequential process necessary to load a propellant tank with densified propellants. This report

details the tests that were conducted at NASA Plum Brook Station in Sandusky, Ohio to demonstrate the

ability to load DLH 2 into a subscale propellant tank.

Lockheed Martin Michoud Space Systems (LMMSS) personnel have developed an analytical tool that models

the loading of a tank of specific geometry with densified liquid hydrogen. For a propellant tank filled with normal

boiling point (NBP) liquid hydrogen, and a specified external heat flux, the tool models the total time required to

replace the NBP liquid hydrogen with densified liquid hydrogen and the final fluid conditions.

The test program described here was conducted to demonstrate the ability to load a scale model propellant tank

with densified liquid hydrogen and to validate the LMMSS analytical model. The plan was to produce, in a batch

process, densified liquid hydrogen and then transfer it to a scale model propellant liquid hydrogen tank. This test

program was conducted jointly through a Space Act Agreement between NASA Glenn Research Center in

Cleveland, Ohio, and Lockheed Martin Michoud Space Systems in New Orleans, Louisiana.

NASA/TM--2001-209391 1
TESTOBJECTIVES

Thepurposeofthetestsreportedherewastoperformthesequential propellant tankloadingandsimulatethe

recirculationprocessusingDLH2propellant withatankconfigurationthatistraceabletoRLV.Thetestswere

designedtocharacterizeanddemonstrate tankthermal stratification, anecessaryrequirement forthedefinitionof

optimumloading,densifierdesignandproductionoperationsintheRLVenvironment. Another important objective

was to evaluate the thermal conditions at which LH 2 could be maintained in its subcooled state during a simulated

recirculation of DLH 2. Furthermore, a subscale tank loading demonstration program could provide the data and

information necessary to firmly ground the analytical tank models developed by LMMSS. The specific test objectives were as follows:

1. Characterize the LMMSS Multilobe tank environmental heat leak.

2. Produce batch quantities of 27 R LH 2 working fluid in a facility dewar to simulate tank recirculation of densifted propellant.

3. Demonstrate the ability of LH 2 to flow upwards out of the tank via a vertical siphon.

4. Evaluate "load-and-go" tank filling with DLH 2 on an ambient temperature and prechilled Multilobe tank.

5. Demonstrate and verify tank thermal stratification characteristics over a range of inlet LH 2 recirculation flow

rates.

6. Obtain sufficient LH 2 thermodynamic data of tanking operations to allow validation of mathematicalanalytical tank models developed.

FACILITY AND TEST HARDWARE

Test Facility

The K-Site test facility at NASA Glenn Research Center Plum Brook Station is used for large-scale tests that

utilize liquid hydrogen. Utilities were provided for filling, pressurizing, draining, and inerting the Multilobe Tank.

The Multilobe Tank was situated within a structural steel frame, which had a roof to protect the tank, as well as

scaffolding to provide access to the tank and piping. The tank sat on a platform ~4 ft above grade.

Liquid hydrogen was provided at the site with two liquid hydrogen trailers. The capacity of each trailer was

13 250 gal. Working pressure for each trailer was 100 psig. One trailer (designated H24) was used to produce densifled liquid hydrogen by pulling vacuum on the ullage using vacuum pump VP-5. VP-5 was a mechanical vacuum

pump with a capacity of 850 ft3/_] fi-_ST-_ifi_dto_!!0_ _h-e-uii-_-T6 _ee ne-gatlv_ presstirelThe Sec0nd

trailer (designated H25) was used as a catch tank during the recirculation simulation.

Liquidhydrogen was transferred from the trailers t0 the tesi tank through 2 in. vacuum-jacketed piping. Piping

was also provided for venting the tank ullage, and pressurizing the tank with either gaseous hydrogen or gaseous

helium. A schematic of the test facility is shown in figure 1.

Instrumentation was provided to monitor test and facility parameters. Temperatures, pressures, liquid hydrogen

flow rates, and tank strains were all m0nit0red_ Data was recorded using a facility data acquisition system. Data _as

updated once per second, and could be recorded at the rate of I scan/sec, 1 scan/10 sec, or 1 scan/min. The total

number of channels monitored was 364.

Test Article

The Multilobe Liquid Hydrogen tank is fabricated from composite material, and consists of two lobes. Each

lobe measures 5 ft in diameter, is 17 ft long, is joined at a 10° angle, and contains a barrel section, a web and two

domes. The lobe to lobe joint contains a continuous 1/4 in. K-type Raco seal. The joint is assembled with 176

(5/8-in.-diameter) bolts. The assembled tank is covered with foam insulation to prevent ice formation and to maintain liquid hydrogen temperatures.

Tank empty weight is 1500 lb. Total tank volume including ullage is ~483 fi3. Surface area of the tank is estimated to be -400 ft 2.

NASAH'M--2001-209391 2
GH2Vent

t |IK \- _ I o ,, _ vE_

/ |12_ \ PT- pressure transducer _ _ (_P-S2P--H---_

/ III \ FM - Flow Meter I 1 1 # _ o_.

i II _ sD" silicon Diode I L_ I, -_ '

' GH2 VENT NORTH /JL'\ .o.,,

/ III _ BURNOFF

Figure 1 .--Multilobe Tank Thermal Stratification Simplified Schematic.

There are two inlet ports, one in the bottom of each lobe of the tank, These inlet lines are 1-1/2 in. pipe size

flanged connections. There are two outlet ports, one in the top of each lobe of the tank. The outlet port in lobe one is

a vapor vent line. The outlet port in lobe two is a siphon line to drain liquid from the top of the tank. The end of the

siphon line is located -24 in. below the top of the tank.

INSTRUMENTATION

The Multilobe Tank was instrumented with a number of silicon diode temperature sensors. These sensors were

located inside the tank. Several silicon diodes were mounted on the wall of the tank, several were mounted on the

web connecting the two halves of the tank. The balance of the silicon diodes were mounted on rakes inside the tank,

and were used to monitor the temperature profile of liquid inside the tank. There were two rakes, one mounted in

each lobe. A schematic indicating the location of these silicon diodes is shown in figure 2. A total of 54 silicon

diodes were monitored during testing to determine the LH 2 temperature profile in the tank.

TEST MATRIX

For the tests reported here, densified LH 2 was generated inside supply dewar H24 by gradually reducing pressure over the fluid with the vacuum pumping system. The dewar pump-down time from 15 to 1.5 psia took

between 12 and 16 hr. Once DLH 2 at the target temperature of 27 R was produced, it was pressure transferred from

dewar H24 into the bottom of the Multilobe tank while normal boiling point fluid was siphoned off the top. This

flow scheme (filling DLH 2 from the bottom while siphoning warmer LH 2 from the top) provides the best method for

filling the tank with densified propellant (ref. 3). The liquid siphoned off the top of the tank flowed to the second

dewar H25. Table I is a summary of the tests.

ANALYTICAL MODEL

The mathematical simulation of the densification process developed by LMMSS is based upon a multiple-node,

Lagrangian approach in which the liquid is subdivided into a number of moving small bundles of fluid. The model is

called the Multilobe, MultiLayer Densification Model (ML2DM). The diagram in figure 3 shows the general schematic of the model for a number of different multiple lobe tank configurations.

NASA/TM--2001-209391 3
Left

Rake

Y

nornfnal

liquid leve71 *"

! 3ft ..... Y

Measurement every 6 inch

for approximately 3 ft long

transverse mast.

Right

Rake

"l_e'as'L;re_'c;n't'every 12 inch

above nominal liquid surface

m i

Measurement every 6 inch

for 3 ft below nominal liquid

surface

Measurement every 12 inch

down to bottom of rake

vertical mast.

_.. oordinate -,'........

Reference

•-Rake \"_ O I

_'""t Web"" t _ (_-]-_ReI'(X=0) +X

--t_A

Figure 2.--Silicon diode rake subassembly installation for test tank.

Test

number

TABLE I.--TEST MATRIX

Test description Tnitial tank

conditions

I Recirculation simulation

Number of fill

lines used

LIt_, transfer

flow rate,

Ibm/see

0.0

Run time,

min

Tank pressure,

psia

Boil off Filled w/NBP LH__ rL'a 125 I5

Saturated siphon Filled w/sat'd LH: 2 0.6 1.5 25 30

at 30 psia

Straight load-and-go Empty, Ambient 2 1.5 155 18 20

Pre-chilled load-and-go Emp_', Cold 1 1.5 250 18 - 20

Recirculation simulation Filled w,NBP LH_, 1 0.5 120 30

Recirculation simulation Filled w,'NBP LH2 I 1.0 60 30

Recirculation simulation Filled w,qqBP LH_, 1 1.5 40 30

Filled w/NBP LH: 2 0.5 90 30

Filled w,q'ffBP LH: 0.5 125 30

NASA/TM--2001-209391 4
1 Lobe 2 Lobe 3 Lobe 4 Lobe

::--- -_--

Figure 3.--General schematic of ML2DM.

2.5

2

= 1.5

1.

0.5.

0 "

-0.5

0

Boundary layer profiles

_0.8

0.6

0.4

0.2 T,

0

-0.2

0.2 0.4 0.6 0.8 1

y18

Y

Figure 4.mBuoyancy driven boundary layer temperature and velocity profiles.

transition from laminar

to turbulent

The fluid is subdivided into the separate lobes of the tank and then further subdivided into layers. During the

recirculation cycle, subcooled fluid is flowed into the bottom of the tank and warmer fluid is siphoned from the

upper portion of the tank. Within the simulation, as the fluid enters, nodes are created at the bottom of the tank. The

conditions of each node are then tracked as it is pushed upward by the recirculation process. At the top of the tank

where fluid is being removed, the nodes shrink and eventually collapse.

In addition to the slow bulk movement of the liquid caused by the recirculation flow there are a handful of other

significant effects that control the effectiveness and efficiency of the densification process. One of these is the formation of buoyancy driven boundary layer flows and another is the lobe-to-lobe interaction of the fluid. Both of

these phenomena are discussed in somewhat more detail.

Buoyancy driven boundary layer flow is significant in the densification process because it causes a redistribution of the energy within the tank. The continuous heat leak into a nonvacuum jacketed propellant tank can be quite

significant. This influx of energy tends to work against the densification process which is, at its core, essentially a

bulk enthalpy lowering exercise. However, due to the existence of buoyancy driven boundary layer flow, the detrimental effects of the continuous heat leak is significantly minimized since it tends to draw the fluid warmed along

the walls upward towards the top of the fluid where it can be siphoned off. Thus, this boundary layer flow amplifies

the thermal stratification within the tank and thereby enhances the densification process.

In figure 4 the assumed velocity and temperature profiles are shown along with a simple schematic of the fluid

near the tank sidewall. There are no exact analytical solutions to the governing differential equations for motion and

temperature distribution of the fluid within such a thermal convection boundary layer of fluid along the sidewall of

the tank. The fluid boundary layer profiles used in this analysis come from a unique approximate solution in which

the temperature profile follows a third order polynomial and the velocity profile follows a fifth order polynomial.

All of the boundary conditions imposed at the wall and at the boundary layer to bulk fluid interface are satisfied by

NASA/TM--2001-209391 5
this system of equations though conservation of energy is not satisfied along the full breadth of the profile. This fact

is compensated by the assumption that the boundary layer thickness is proportional to the Grashoff number to the

l/4th power in the laminar region and to the 1/3rd power in the turbulent region. The empirical nature of these last

correlations, largely verified by this testing, far outweighs the slight errors inherent within the approximate solution

to the boundary layer equations. The result is a straightforward algorithm, which correlates well with the test results

presented in the next section.

The second significant feature of the analytical model and the second significant phenomenon occurring within

the tank during the densification process is the lobe-to-lobe interaction of the fluid. This is especially significant to

the densification process when the inflow, outflowl and/or tank configuration has a large asymmetry as was the case

for these tests where inflow and outflow was located in different lobes. The Multilobe tank described within this

paper is a two-lobe configuration with a single separating septum. This septum is not solid, but it does offer some

restriction in the lobe-to-lobe cross flow. The simulation handles the calculation of this cross flow by first reducing

the number of lobe-to-lobe, node-to-node interactions into eleven possibilities, These interaction possibilities for

each combination of adjoining, moving nodes is evaluated at a given time step and is then superimposed against the

fixed geometry of the septum. The relative fluid flow resistance and fluid acceleration damping used within the

simulation was based on standard orifice flow" calculations. The model to test data comparisons presented in the next

section confirmed the validity of using such values.

Other features of the model include a single node, multiple gas ullage simulation, bulk boiling and surface condensation algorithms, as well as an approximate algorithm to simulate convection motion of the bulk fluid.

TEST RESULTS

The results from the testing can be broken into three categories. First there was the saturated siphon test which

was an operations demonstration. Second, there were two "load and go" tests, which were attempts to demonstrate

potential alternative tank loading methods with densified propellant. Third, there were five recirculation tests that

were intended both to fully demonstrate the baseline densification process and to provide data for the validation of

the analytical model.

The saturated siphon test was intended to demonstrate the fact that saturated cryogenic fluid could be flowed

upwards and out of the tank via a vertical siphon. The fluid in the tank was fully saturated at -30 psia and then flow

was initiated. Because the fluid was static and saturated within the tank initially, the rise to a higher elevation and

the acquisition of velocity should have cavitated the fluid slightly. The question going into the test was whether this

low level cavitation would be detrimental to the siphoning process.

Figure 5 shows two plots. The first is the inflow of liquid hydrogen to the tank while liquid hydrogen flowed

out the siphon. Because the liquid level within the tank was held constant and because there was little or no thermal

stratification within the tank, the outflow up the siphon is equated to this inflow value. Reasonably steady flow was

obtained at both a lower value (-0.7 lbm/sec) and at a higher value (-1.6 lbm/sec). The second plot in figure 4

shows the measured temperatures both in the vicinity of the siphon inlet within the tank and in the siphon line itself.

This confirms, based upon the tank pressure, that the fluid was fully saturated.

2.5000.

2.0000 -

i

i 1.5000 -

I I_0-

05000 -

00000.

4000

Mass Flow Into the Test Tank During

"Saturated Siphon Test"

4200 44100

I

4600 48OO

t_ma(s)

Fluid Temperatures in the Siphon Line and Within

Tank During "Saturated Siphon Test"

4_

_ -- SD-P03(s_phonr_)

44_ I I_J_ ' ....... SD-L2V03 (tank a_siphon level)

i --

!4,;_.//' .........................

14,i W

40 _-

I . I 39 ! t : _

5000 5200 5400 40(30 4200 4400 4600 4800

time (s)

Figure 5.--_turated siphon test results.

_ t

5OOO 520O

I

54OO

NASA/TMI2001-209391 6
Thesecondcategoryof testsundertakenweretwo"loadandgo"tests.Thepurposeof these tests was to load

densified propellants directly into an empty tank with no recirculation. If this could be done on a launch vehicle such

that an acceptable degree of overall bulk subcooling was achieved, then there would be no need to have a recirculation system in place. The first "load and go" test, called the "straight load and go," began with a warm empty tank.

For the second "load and go" test, called the "prechilled load and go," the tank was first prechilled by filling with

normal boiling point fluid, then drained, and then refilled with the densified propellant.

The results from the straight load and go test are presented in figure 6 and the results from the prechilled load

and go test are presented in figure 7. Each of these plots shows the temperature time histories of the various silicon

diode temperature measurements mounted on the vertical rake within the tank. As the tank was filled from the bottom, the diodes fell into place at cryogenic temperatures. The diodes at the bottom of the tank near the in-flowing

subcooled liquid became and remained the coldest. However, as the fluid rose it picked up heat so that by the time

that the uppermost diode saw liquid it saw nearly saturated fluid. The prechilling of the tank appeared to alleviate

this effect somewhat as the temperatures were generally lower through the tank than during the "straight load and

go" test. However, neither loading scenario achieved a complete top-to-bottom subcooling of the liquid. Also, in

both of these cases, as soon as the liquid inflow was stopped the overall bulk temperature rose quickly. If this tank

had been within a flight vehicle on the launch pad experiencing a prelaunch hold it is likely that the undensifying,

expanding liquid would have been expelled out the vent.

The final category of tests undertaken within this test plan were five recirculation and densification tests run at

various inflow rates and configurations. These tests were intended both to fully demonstrate propellant densification

as it would be applied to a launch vehicle and to validate the mathematical simulation of the in-tank densification

process. There were five tests, listed as Test 5 to 9 in table I. Plots for Test 5 to 9 are shown in figures 8 to 12,

showing comparisons between simulation reconstructions of the test conditions and the actual test data itself after

completion of loading with DLH 2. The test data points presented are the silicon diode temperature measurements

up the vertical rakes, one in each lobe, and the lines of simulation output are the predicted thermal stratification

Straight Load and Go Test:

Lobe I Stratification History

, i _ ' _

1 I I t I

time

O.

E

Straight Load and Go Test:

Lobe 2 Stratification History

q I I I f , I l

time

Figure 6._Straight load and go test results.

I.

Pre-Chilled Load and Go Test:

Lobe Stratification History

time

_5

.=

Pre-Chilled Load and Go Test:

Lobe 2 Stratification History

time

Figure 7._Prechilled load and go test results.

NASA/TM--2001-209391 7
Test 5 Temperature Profile: Lobe 1

vertical height

L_

Test 5 Temperature Profile: Lobe 2

li • • • • •iN

i vertical height

Figure 8.•Test 5 thermal stratification profiles at end of DLH 2 fill.

Test 6 Temperature Profile: Lobe 1

vertical height

Test 6 Temperature Profile: Lobe 2

vertical height

Figure 9.•Test 6 thermal stratification profiles at end of DLH 2 fill.

Test 7 Temperature Profile: Lobe 1

Y

m• m

vertical height

Test 7 Temperature Profile: Lobe 2

I ) _ F

vertical height

Figure 10.•Test 7 thermal stratification profiles at end of DLH2 fill.

I

]

Test 8 Temperature Profile: Lobe 1

J _ I I I

vertical height

Test 8 Temperature Profile: Lobe 2

)

/

) ) ¢ ,¢ -_, I I

vertical height

Figure 11.--Test 8 thermal stratification profiles at end of DLH2 fill.

NASA/TM--2001-209391 8
Test 9 Temperature Profile: Lobe 1

I t i I E I

vertical height

Test 9 Temperature Profile: Lobe 2

ve ica, hg. 

Figure 12.--Test 9 thermal stratification profiles at end of DLH 2 fill.

TABLE 11, APPROXIMATE ERROR 1N

LOADED MASS

Test

5

6

7

8

9

Description Approximate error

in loaded mass,

percent

=0.5 lbm_s 0.53

1 inlet

=1 lbm/s 0.33

1 inlet

= 1.5 lbm/s 0.16

1 inlet

=0.5 lbm/s 0.06

2 inlets

=0.5 lbrrv's 0.36

1 inlet

profiles. Such data to simulation comparisons were made at many points along the densification timeline but due to

space restrictions only the steady state plots are presented.

For nearly all the tests, the agreement between the measured test data and the simulation was quite good.

Table II summarizes the accuracy of the simulation based upon estimated total mass loaded within the tank. Total

mass was estimated from final fluid density and the tank geometry. With the exception of one test, Test 5 the first

recirculation test conducted, all of the error values are within the accuracy range resulting from the accuracy of the

diodes. The attempt to come to a better understanding of the relatively large error on Test 5 is ongoing.

CONCLUSIONS

Data collected from this test program leads to the following observations and conclusions:

1. Environmental heat leak into the Multilobe tank was consistent with. predictions.

2. Saturated liquid hydrogen can be flowed upwards and out of the tank via a vertical siphon, proving that

siphoning saturated liquid hydrogen from the top of the tank will not adversely affect recirculation.

3. Neither "load and go" loading scenario (either with a warm tank or a prechiUed tank) achieved a satisfactory

top-to-bottom subcooling of the liquid.

4. For recirculation simulation tests, agreement between measured test data and analytical predictions was

good, which validates the model.

5. Tank thermal stratification characteristics over a range of inlet LH 2 recirculation flow rates was demonstrated and verified.

NASA/TM--2001-209391 9
REFERENCES

1. Tomsik,T.,"PerformanceTstsof aLiquidHydrogenPropellant DensificationGroundSystemfortheX33/

RLV"(NASATM-107469, AIAA-97-2976,i997).

2.Bailey,T.,Vandekoppel, R.Skardtveldt, G.,andJefferson, T.,"CryogenicPropellant StratificationAnalysis

andTestDataCorrelation" AIAA Journal, Vol. 1, No. 7, pp. 1657-1659, 1963.

3. Fazah, M.M., "STS Propellant Densification Feasibility Study" (NASA TM-108467, 1994).

4. Greene, W. and Vaughan, D., "Simulation and Testing of In-Tank Propellant Densification For Launch

Vehicles" (AIAA-98-3688, 1998).

5. Incropera, F., and DeWitt, D., Fundamentals of Heat and Mass Transfer (John Wiley & Sons, 1996).

6. Lak T., Lozano, M., and Tomsik, T., "Advancement in Cryogenic Propulsion System Performance through

Propellant Densification" (AIAA-96-3123, 1996).

7. Anthony, M. and Greene, W., "Analytical Model of an Existing Propellant Densification Unit Heat Exchanger"

(AIAA-98-3689, 1998).

8. White, F.M., Fluid Dynamics (McGraw-Hill, 1979).

NASA/TM--2001-209391 I 0

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1. AGENCYUSEONLY(Leaveblank) 2. REPORTDATE 3. REPORTTYPEAND DATESCOVERED

September 2001 Technical Memorandum

4. TITLE ANDSUBTITLE 5. FUNDINGNUMBERS

Testing of Densified Liquid Hydrogen Stratification in a

Scale Model Propellant Tank

6. AUTHOR(S)

John M. Jurns, Thomas M. Tomsik, and William D. Greene

7. PERFORMINGORGANIZATIONNAME(S)ANDADDRESS(ES)

National Aeronautics and Space Administration

John H. Glenn Research Center at Lewis Field

Cleveland, Ohio 44135-3191

9. SPONSORING/MONITORINGAGENCYNAME(S)AND ADDRESS(ES)

National Aeronautics and Space Administration

Washington, DC 20546-0001

WU-721-20-00-00

8. PERFORMINGORGANIZATION

REPORTNUMBER

E-11820

10. SPONSORING/MONITORING

AGENCYREPORTNUMBER

NASA TM--2001-209391

11. SUPPLEMENTARYNOTES

Prepared for the 1999 Cryogenic Engineering and International Cryogenic Materials Conference sponsored by the

Advances in Cryogenic Engineering, Montreal, Quebec, Canada, July 12-16, 1999. John M. Jurns, Dynacs Engineering

Company, Inc., 2001 Aerospace Parkway, Brook Park, Ohio 44142; Thomas M. Tomsik, NASA Glenn Research Center;

William D. Greene, Lockheed Martin Michoud Space Systems, Huntsville Operations, Huntsville, Alabama. Responsible

person_ Thomas M, Tomsik t organization code 5870, 216-977-7519.

12a. DISTRIBUTION/AVAILABILITYSTATEMENT 12b. DISTRIBUTIONCODE

Unclassified - Unlimited

Subject Categories: 18, 20, and 28 Distribution: Nonstandard

Available electronically at htto://_ltrs._rc.nasa._ov/GLTRS

This publication is avhilable from the NASA Center for AeroSpace Information, 301-6214)390.

13. ABSTRACT(Maximum200 words)

This paper describes a test program that was conducted at NASA to demonstrate the ability to load densified LH 2 into a

subscale propellant tank. This work was done through a collaborative effort between NASA Glenn Research Center and

the Lockheed Martin Michoud Space Systems CLMMSS). The Multilobe tank, which was made from composite materials

similar to that to be used on X-33, was formed from two lobes with a center septum. Test results are shown for data that

was collected on filling the subscale tank with densified liquid hydrogen (DLH 2) propellant that was produced at the

NASA Plum Brook Station. Data is compared to analytical predictions. Data collected for this test series agrees well with

analytical predictions of the environmental heat leak into the tank and the thermal stratification characteristics of the

hydrogen propellant in the tank as it was filled with DLH 2.

14. SUBJECTTERMS

Hydrogen; Hydrogen fuels; Hydrogen production; Cryogenic fluids;

Cryogenic rocket propellants

17. SECURITYCLASSIFICATION

OFREPORT

Unclassified

NSN 7540-01-280-5500

18. SECURITYCLASSIFICATION

OFTHISPAGE

Unclassified

19. SECURITYCLASSIFICATION

OFABSTRACT

Unclassified

15. NUMBEROFPAGES

16

16. PRICECODE

A03

20. LIMITATIONOFABSTRACT

Standard Form298 (Rev. 2-89)

Prescribed by ANSI Std. Z39-18

298-102

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