NASA Technical Memorandum 102535 . ,

High Speed Commercial Transport

Fuels Cons;iderations a,nd _- ._

_-_ Research Needs

C.M. Lee and R.W, Niedzwiecki ...........

Lewis Research Center ................

Cleveland, Ohio ........

............... Prepared for the

Symposium on the Structure_of Future Jet Fuels !!

sponsored by the American Chemical Society

' _ Miami Beach, Florida, Septemberl0-15, I989

(NASA-TM-102535) HIGH SPEEO COMMERCIAL

TRANSPORT FUEL5 CONSIDERATIONS ANO R_SEARCH

NE_DS (NASA} I0 p CSCL 21 _

1_90-21869

unclas

G3128 0280096

HIGH SPEED COMMERCIAL TRANSPORT FUELS CONSIDERATIONS

AND RESEARCH NEEDS

By

C. M. Lee and R. W. Niedzwlecki

National Aeronautics and Space Administration

Lewis Research Center, Cleveland, Ohio 44135

FUELS WORKSHOP

co

uo

!

The National Aeronautics and Space Administration Agency (NASA) is advocating a new initiative in commercial aeronautics that has the goal of reducing long-range flight times by as much

as 75_. The HSCT Program is focused on establishing the technical feasibility, economic practicallty, and environmental acceptability of an advanced high-speed commercial transport for potential implementation early in the next century.

As part of the ongoing HSCT studies, issues regarding fuel impacts received much initial

concern. Fuel capabilities and economics are very important in determining viable flight speeds.

In addition, operation at supersonic speeds provide different and far greater potential difficulties

regarding the fuels than is encountered during subsonic flight, due to the high temperature environments. HSCT fuels will not only be required to provide the energy necessary for flight, but will

also be subject to aerodynamic heating and, will be required to serve as the primary heat sink for

cooling the engine and airframe. To define fuel problems for high speed flight, a fuels workshop

was conducted at the NASA Lewis Research Center (LeRC) during October 14-15, 1987. The purpose of the workshop was to gather experts on aviation fuels, airframe fuel systems, airport infrastructure and combustion systems to discuss nigh speed fuel alternatives, fuel supply scenarios

increased thermal stability approaches and measurements, safety considerations, and to provide

directional guidance for future R and D efforts. Participants included representatives of nine

government agencies and sixty-two corporations.

The major conclusions from the workshop include the following:

I. Both Thermally Stable Jet Fuels (TSJF) and Liquid Methane (LCH4) should continue to be

studied as viable candidates for supersonic commercial transports. Endothermic fuels are viable

for military missions but due to their high cost and the preliminary stage of development regarding

their usage, are not current candidates for commercial aircraft. TSJP fuel technologies were

deemed to be sufficiently in-hand to project their usage in the 2000-2010 time frame. LCH 4 usage

would require much development regarding aircraft storage and pumping, airport infrastructure requlrements, potential and perceived safety problems and regulatory aspects, Thus LCI-I4 fuels,

while offering certain advantages such as increased flight speeds, would require more time for implementation possibly beyond the year 2015. The general workshop conclusion was that both TSJP

and LCH4 should continue to be studied, but for different time frames.

2. For TSJP evolution of a quantitative test method for determining thermal stability is

very much required. The widely used Jet Fuel Thermal Oxidation Tester (JFTO_ produces qualitative pass/fail results and is not readily adaptable to usage with higher thermal stability fuels.

What is required is a test method capable of simulating thermal stability conditions encountered in

high speed flight. These are: Long residence times in fuel systems to which the fuel is subjected

to modera[e to high heat loads: and, conditions of very high heat flux at short residence times which

fuels encounter in their passage through fuel struts and injectors.

3. Considerable workshop discussion centered around issues regarding what the thermal

stability of current fuel being supplied to airport s around the world actually is. Opinions were

offered that refinery products available for aircraR usage has changed considerably over the last

several years. The principal reason offered for this is that the manufacture of lar_oe quantities of

non-leaded gasoline has made a better product available. Thus, it was suggested that fuels from

airports around the world be obtained and their thermal stability determined. Fuel samples should

also be obtained and their thermal stability determined. Fuel samples should also be obtained from

refineries and, where possible, their thermal stability shoulJ be compared to the airport fuels.

Direct comparisons would be difficult to make in many instances due to the co-mingling of various

jet fuels at airports. However, direct comparisons could yield conclusions regarding the deterioration of fuel thermal stability due to shipment and airport storage.
4. On-line treatment of jet fuels to improve their thermal stability was also recommended.

Implicit in the recommendation is the difficulty and cost that would be presented by supplying two

commercial transportation fuels-one for the subsonic fleet and one for the supersonic fleet. Online treatment would consist of processing Jet A fuel either prior to or during fuel loading. Treatment techniques cited included deoxygenation and/or clay filtering. Both techniques have previously

indicated substantial improvements in thermal stability. However, much work is required to

quantify the potential improvement.

5. Flight roach number, heat loads, methods and type of aircraft tankage, fuel system tTpe,

etc. require definition prior to being able to define specific fuel needs. This data will become

available as aircraft studies, currently in process, proceed. In the interim, fuels with increased

thermal stabilities, compared to Jet-A, of 50°F, 100°Fand 150°F were defined. Regarding LCH 4

fuels, recommendations centered on determining airport infrastructure issues and costs, safety

and regulator), aspects prior to the initiation of research to enhance their implementation.

The workshop also identified seven potential non-cryogenic high speed liquid fuel candidates,

which are listed in Table I. The associated features, research needs, and delta cost also are

included.

AIRPORT INFRASTRUCTURE AND SAFETY IMPACTS ON HSST

Since fuel price can represent 3096 to 45_ of the Direct Operating Costs (DOC) for an advanced HSCT (at fuel prices from 0.50¢ to _1.00 per gallon, Figure 1) it is important that all major

cost factors be considered. Thus, it was necessary to estimate He incremental cost associated

with infrastructure and operations at the airport. TMs was accomplished by a team consisting ot

NASA LeRC and Langley Research Center personnel as well as Boeing and McDonnel Douglas personnel. Consensus resuir_ are summarized in three figures and one table: Figure 2 shows that the

infrastructure and s[0rage costs are function of daily LCH4 usage in tons per day. The four solid

data points Were?l{ose:reached5) _conse_°_ _a_ c __n_e_r[z-_-facility:cost grow_factots (or slx-tenths factor) for each segment; similar infrastructure and handling costs for TSJF are

presented in Figure 3. TSJF costs were determined to be substantially lower than those for LCH 4

and were assumed to be independent of daily fuel consumption rates. The total fuel costs (including

refinery/liquification plant prices plus airport infrastructure costs) and sensitivity ranges are

shown in Figure 4. "l"aese fuel costs with the sensitive price ranges that are being used in the ongoing HSCT studies are shown in Table If.

From the Tables I and if: and Figure i, it is likely that highly hydrogenated jet fuel can inCrease thermal Stability an additional 150°F higher than current jet fuels. For implementation,

both TSJF and LCH4 must be environmental viable. That means, the fuel has to be clean burning

with very low concentrations of metal and sulfur content. The injection of particles and/or metals

into the stratosphere can produce potentially adverse effects on the environment. In addition to the

airport fuel infrastructure cost determinations, airport safety issues were also investigated. The

general consensus of airport safety considerations for the usage of TSJF and LCH 4 are concluded

in below:

SAFETY CONSIDERATIONS FOR THERMALLY STABLE JET FUELS

- In general, fuel characteristics affecting safety (volatility, flammabilit T, toxicity, etc. )

should be no different than those of present jet fuels.

- Separate limited-u_e transfer and distribution systems add to the need for leak and hazard

sensing and controls.

- Airport clay filtration treatment requires environmental controls for filter changing and

cleanup.

- Airport processing, such as deoxs'genation, adds concerns for leak, over presure, and

over temperature sensing and protection.

- Thermal stability additive treatment may require handling and environmental protection

from toxic chemicals.

GENERAL PROXqSIONS FOR LIQUID METHANE SAFETY

- Under present and proposed legislation, it is unlikely that storage of large quantities of

liquid methane would be permitted at airports.

- The standards in national fire protection association NFPA 59A are the bases for nearb

all domestic and foreign liquid natural gas storage and handling.

- Local r_ulations may be more resLrictive than NFPA 59A, especially near populous

coast cities.

- Airport safctr regulations are presently undefined.
- Solving the technical and economic problems of safe handling of liquid methane may not

satisfy the political, regulatory and environmental issues.

FUEL SYSTEM AND THERMAL 'MANAGEMENT REQUIREMEN'I'S

At subsonic flight speed, the fuel properties reqtdred to satisfy en_ne demands are heat of

combustion, combustion characteristics, lubricity, viscosity, heat capacity, vapor pressure,

thermal stability, freeze point, and flash point, etc. As flight speeds increase into the targeted

Mach 2-3+ regime, in addition to these engine requirements, fuels have to satisfy various demands

for cooling. Included in these cooling demands are cooling of aircraft/propulsion systems; thermal

control of fuel storage and distribution systems; and cooling of propulsion lubriqation systems. Thus,

a proper thermal management of the high speed aircraft/propulsion system is required to satisfy

these various cooling demands. This thermal management system has to provide sufficient heat

sinks to absorb the rejected heat loads from the aircraft/propulsion system. At subsonic or low

supersonic flight speeds, heat sinks are primary provided by ambient air and fuel. Below Much 2,

ambient air is adequate to satisfy most of the cooling demands. The fuel plays a secondary role as

a heat sink. Between Mach 2 to 3+, the rapid increased stagnation temperature reduces the cooling

capability of the captured air, therefore placing more demands on the fuel as a heat sink. The heat

sink capacity of fuels depends on several factors. These are: storage condition in fuel tank, fuel

thermal stability, maximum heat adsorption, fuel flow rate, etc. These factors are not yet completely defined. Thus, subsequent studies in the following areas are needed to define thermal management requirement:

1. Interactive airframe/propulsion studies.

2. Quantification of thermal demands of both the airframe and propulsion system.

3. Optimization of thermal demands of both the airframe and propulsion system.

4. Definition of critical system components.

5. Definition of critical operating condition.

6. Definition of the shortcomings of existing fuels.

ANALYTICAL WORK

It is difficult to predict future aviation fuel prices. However, it is possible to use a computer code to estimate aviation fuel costs. At LeRC a Refinery Simulation Program (Gordian code)

was used to estimate future fuel costs. This program will be used to predict the flow streams and

material, energy, and economic balances of a typical petroleum refinery, with particul, ar emphasis

on production of aviation turbine fuel of varying end point and hydrogen content specifications. The

program has provision for shale oil and coal oil in addition to petroleum crudes. The primary

features of the Gordian code are:

I. The flexibility to configure a refinery involving any or all of the process units commonly

employed in the production of gasoline, jet fuels, and mid-distillates.

2. The ability to produce jet fuel blends of varying end-point specification and var_-ing

specified hydrogen content as part of the total slate of products.

3. The ability to handle synthetic crudes (shale and coal derived) with varl-ing severities

of hydroprocessing.

4. The determination of overall refinery energy efficiency.

5. The determination of sulfur, nitrogen, and hydrogen material balances for each process

unit and for the overall refinery, and

6. The capability of conducting economic calculations.

In 1988, this code was modified to include three additional capabilities:

a. Allow the initial boiling point of jet blend to be specified.

b. Allow the hydrotreated and hydrocracker units to specify the level of severity of hydrotreating.

c. Simplify updating the parameters used to estimate the economics (i.e. construction

costs, chemical costs, labor costs).

A case study utilizing this code is presented below. The case study considered both petroleum crude and shale crude processe_ in a mid-size refinery to produce JP-7 type jet fuel. The

produced jet fuel properties have the following constraints:

Initial boiling point is 360°F, end.point is 550°F, freezing point below -43°C, aromatic content below 5%. The minimum hydrogen weight percent of 14_ is then varied to determine economic

impact. Figure 5 shows a schematic diagram of the refinery configuration for this study. The feed

rate is 70,000 barrel/day (BPD) of East Texas petroleum based crude and 30,000 BPD Garrett

shale oil. The process units used are listed in Table IIT. The capacity for each process unit is

defined at 110% of the actual feed rate in all the cases studied. The product stream rate from each

process unit and its properties are listed in Table IV; the economic analysis of changing hydrogen

3
weight percent of blended jet fuels are listed in Table V; it should be noted that in Table V, the esf_-

mated cost is not kacluded in the cost of crudes. As an anticipated result, the higher the hydrogen

weight percent of the fuel, the higher the cost and the lower the amount of jet blend product.

SUMMARY

The results of HSCT fuels studies can be summarized as follows:

1. Both thermally stable jet fuels (TSJF) and liquid methane (LCH 4) should continue to be

studied as viable candidates for supersonic commercial transports. Endothermic fuels are viable

for military missions but, due to their high cost and the preliminary stage of development regarding their usage, are not current candidates for commercial aircraft. TSJF fuel technologies were

deemed to be sufficiently in-hand to project their usage in the 2000-2010 time frame. LCH 4 usage

would require much more development regarding aircraft storage and pumping, airport infrastructure requirements, potential and perceived safety problems and regulatory aspects. Thus, LCH4

fuels require more time for implementation-possibly beyond the year 2015.

2. The _-ldely used JFTOT is a qualitative on/off indicator, which is not readily adaptable

to usage with higher thermal stability fuels. An innovative device which can quantatively determine

fuel thermal stability in high speed flight is much needed.

3. It was concluded that determination of the thermal s_ability for current fuels being supplied to airports around the world be accomplished via two approaches: first, obtain fuel samples

from airports around the world and determine their thermal stability. Second, fuel samples from

refineries should also be obtained, and their thermal stability should be compared to the airport

fuels.

4. On-line treatment of jet fuels to improve their thermal stability was desired. This

treatment would consist of processing of Jet A fuel either prior to or during fuel loading. Various

treatment techniques cited, however, much work is required to quantify the potential improvement.

5. Flight roach number, heat loads, fuel system type. and thermal management require--

meats etc., require definition prior to being able to define specific fuel needs. The subsequent

studies are currently in process. In the interim, fuels with increased thermal stabilities, compared to Jet A. of 50°F, 100*F and 150"F were defined.

6. Subsequent airports infrastructure studies concluded that generally. TSJF fuel charactertstics affecting safety should be no different than those of present jet fuels. For LCH4, airport safety regulations are presently undefined, the application of LCH4 in HSCT would require

much development regarding aircraft storage and pumping, airport infrastructure requirements,

potential and perceived safety problems and regulatory aspects.

7, The Gordian cede can be used to predict the flow streams and material, energy, and

economic balances of a petroleum refinery, with particular emphasis on production of a_iation

turbine fuel, this code can be up-dated to include the cost prediction for various fuel treatments.

(i)

LITERATURE CITED

Computer Model for Refinery Operations With Emphasis on Jet Fuel Production, NASA

CR-135334 {1978).

4
FUEL

TABLE 1 - HIGH SPEED LIQUID FUEL CANDIDATES.

COST + FEATURES ,RESEARCH NEEDS

[

JETA CLAY FILTERED

JET A DEOXYGENATED

JET A DEOXYG ENATED

& DESULPHURIZED

HIGH VAPOR PRESSURE

FUEL

HIGHLY HYDROTREATEr

JET FUEL

JP-7

RAFFINATE / SASSOL /

OTHER STREAMS

SMALL +

SMALL +

UPTO

+ 0.10 $/g al

SMALL +

0.105++++

0.105 + +

1.09 $/gal +

0.16 - 0.30 $/gal

SHIPPING

Uses Current Fuel Supply, No Determine Impacts on

:.Special Handling or Storage Thermal Stability of Clay

Modest Improvement in Fuel Filtering, Determine Cost

Thermal Stability _ Increase

i same as Ab0vei0n Board Same as Above

Inerting Required

Modest Improvement in Fuel

:Thermal Stability

i Same as AIo0vei s i_eciai " same as Above ....

;Storage, Tankage Required

Larger Potential Improvement

in Fuel Thermal Stability

' Large Potentiai Tfieimal Stal:)iiity .... Define Storage & Handling

Improvement; Special Storage,

Handling &Tankage Required Requirements; Define

Refnery Streams of Interest

Very Large Thermal Stability Determine Effects of Severe

Increase to Mach 4 Flight Hydrotreating on Thermal

Special Storage with Inerting Stability, Lubricity, Etc.

Sarne as_,5ove ........... Same as Above -

Determine Effects of Hydro

' -b'eating Less Severly

Determine Price Reductions

with Increased Quantity

Identify Other Viable

Refinery Streams

NO IDENTIFICATION OR DESIGNATION

TABLE 2 - FUEL COST ESTIMATES, FEBRUARY4, 1988.

Fuel

Refinery Type Baseline Increased Reference a

of Special Storage & Handling Price

Treatment Cost ( $/Gal) ( $/Gal)

JET A NONE 0.00 0.60

TSJF + 50 OF -More Stable TSJF

From Refinery 0.00 0.60

-Clay Filters at

Air[_orl: Additive

or l)eoxygenation

i. at Storage Tank. ; ........................................ i

TSJF + 100°F Hydrolreated 0.01

TSJF + 150 OF Highly Hydrogen- 0.025 0.90

aled at Refinery

Plus Deciated

. Storage and

Handling at

Airport

OTHERS Alternate b

Refinery Stream

LCH 4 From Liquefaction 0.I0 c 0.58

Plant

Price Range

Total Cost for

( 5/Gal) Sensitivity

0.60 0.50 to 0.75

: 0.60 0.50 to 0.85

0.71

=

0.925 =.

0.60 to 0.95

0.70 to 1.10

0.68 0.50 to 1.00

a FromNovember4, 1987 meetingIncludes$0.01 forairport to aircraftcosts.

b Insufficientdata toestimate.

c 7000 tons per day
TABLE 3 - THE PROCESS UNITS, UNITSCAPACITIES, AND PRODUCT RATESOF THE

CASE STUDY.

Refinery Process Unit Actual Feed Rate (bpd Capacity (bpd)

Petroleum Crude Unit

Shale Crude Unit

Petro, Vac, Dist, Unit

Shale Vac, Dist, Unit

Catalytic Cracker

Gas Oil Hydrocracker

Shale Gas Oil Hydrocracker

Distillate Desulfurizer

Kerosene Hydrotreater

Shale Kero, Hydrotreater

Hydrogen Plant

Coker

70000.0

30000,0

30100,0

16260,0

14156.5

9909,5

1000.0

7990,1

500.0

2500.0

48,8 a

2000,0

77000.0

33000.0

33100.0

179O0.O

15600.0

10900.0

1100.0

8800.0

550,0

2800.0

54.0 a

2200,0

Initial Boiling Point #360,0 °F

En_point = 550,0 -F

Hydrogen Constraint = 14,46 wt%

Petroleum Crude Used: East Texas

Shale Crude Used: Garrett Shale Oil

a Hydrogen flowrate given in MMSCFD.

TABLE 4 - COMPONENT STREAMS OF JET BLEND USINGTHE PARAMETERGIVEN INTABLE 5.

[IBP = 360 OF;EP = 550 OF;MtN. HYD. WT% = 14.4&l

Process Unit Origin

Shale Oil Hydrocracker

Shale Oil Hydrocracker

Gas Oil Hydrocracker

Shale Kero. Hydrotreater

Kerosene/Naptha Hydro tr,

Gas Oil Hydrocracker

Shale Kerosene Hydrotreater

Stream Name

Hy_o.trt. hvy. kero.

Hydro. trt. It. kero.

Hydro. trt. It. kero.

Hydro, trt. It. kero.

Naptha

Desul. hvy. kero.

Hydro. trt. hvy. kero.

Pool Properties

Volumetric

Flowrate into

Jet Blend

(bpd)

13

177

4063

886

133

813

26

6111

Hydrogen

Weight

Percent

15,60

14,85

14,57

14,29

14,14

14, 09

14,05

14, 46

Freezin_

Poing (_C)

- 45.6

-45,6

-45.6

- 37,8

-31,1

- 45.6

- 27.2

- 43.5

Aromatic

Weight

Percent

15,0

15.0

5,0

1,5

1.6

5.0

1.5

4.7

6
ORIGINAL PAGE IS

OF POOR QUALITY

TABLE5 - ESTIMATIONOF OPERATING AND INVESTMENTCARRYING COSTS AS AFUNCTION OF THE

HYDROGEN WEIGHT%.

[IBP= 360 °F; EP = 550 *F.]

Minimum

Hydrogen

Weight %

14.35

14.40

14.45

14.50

14.55

Jet Blend

Freezing Point

(degrees °C_

- 28.2

- 33.6

-42.8

-43,5

Aromatic

Content of

Jet Blend (%)

4.3

4,3

4.3

4.7

Total Amount

of Jet Blend

Produced (bpd',

7520,70

6899.10

6258,48

5541.12

Total Operating and Investment

Carrying Charge per Barrel of

Jet Blend Produced a

9.74

10.62

11.18

12 12

No naptha in Jet Blend

a Does not include cost of crude oil.

1987

TECHNOLOGY

2010

TECHNOLOGY

$.50/GALLON $1.00/GALLON

3% INTEREST

_000 NM 2_0 PAX O_R INFLATION

Figure 1.- Impact offuel price on HSCTDOC + I.

8

FACILITY COST SCALING FACTOR

0.25 _ a. O.6315 (5OOto2OOOtons/day}

l bcl 0.6763 1.000 (2000 ( aboveto 7000 tons/day)

0.20_

0.15_

c

, i

0.10 _- o i o

!INCLUDES Storage&Distribution /

i *.EXCLUDES: Airplane boil- offlo_es J

0.05L _ I ! 1 I I

0 20O0 4000 6000 80O0 1 (3000

DAILY LCH4 UTILIZATION (TONS/DAY)

Figure2, - EstimatedincreaseinLCH4 airportinfrastructure

cost relative tojet A fuel.

0.03

w _ 0.02

i 0.01

i_ 0.0C

Reference costforjet A includes $0.01 for storage & distribution

O

JETA +50 +100 +150

THERMAL STABILITY LIMIT INCREASES, OF

Figure 3. - Estimated increaseinTSJF airport

infrastructure cost relative to jet A with increase in thermal stability limit.
BBBIB TSJF BASELINE TO AIRPORT

TSJF PRICE RANGE FOR SENSITIVI]Y

1.2

f1,0! :_+ 150

400° 5o8 e& 70°0

THERMAL STABILITY LIMIT, OF

LCH4 BASEUNE TO AIRPORT

LCH4 PRICE RANGE FOR SENSITIVITY

500ToWday

2000 Ton/day

7000Ton/day

t __1

1100 ° 1200 °

Figure 4. - Fuel price assumptions.

propane l Hydrogen J hydrogen

| i

e_ane and lighter .... JJlPlant

_ naptha

_ro. ILkemeene

hvykeroeene

L kerosene

 ='rl

g_oil

crude

l Vacuum bottoms

hyd_d naptha and It. kerosene

iil__ It.and hvykero_ne

gasoil

IVBcuum

_t_me

r F

, cydeoi Di_kde hvykeroGene

• ' Dee_dzer *

--_ GmOfl, J _racking J hydrcx:rackedltendhvykerosene

hydro_ut_ It.and hW kerosene

t Hydrocracking SheieGaJOil l hydrocrackedlt.andhvykerosene

coker gu oil

Figure 5. - Schematic diagram of refinery configurarlon.

L

Jet

Blend

8
Report Documentation Page NalionalAeronauticsand

SpaceAdministration

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No.

NASA TM- 102535

4. Title and Subtitle 5. Report Date

High Speed Commercial Transport Fuels Considerations and

Research Needs

7. Author(s)

C.M. Lee and R.W. Niedzwiecki

9. Performing Organization Name and Address

National Aeronautics and Space Administration

Lewis Research Center

Cleveland, Ohio 44135-3191

12. Sponsoring Agency Name and Address

National Aeronautics and Space Administration

Washington, D.C. 20546-0001

6. Performing Organization Code

8. Performing Organization Report No.

E-5345

10. Work Unit No.

535-05-01

11. Contract or Grant No.

13. Type of Report and Period Covered

Technical Memorandum

14. Sponsoring Agency Code

15. Supplementary Notes

Prepared for the Symposium on the Structure of Future Jet Fuels II sponsored by the American Chemical Society,

Miami Beach, Florida, September 10-15, 1989.

"_| -_'.T

16. Abstract

The National Aeronautics and Space Administration (NASA) is currently evah_hting the potential of incorporating High Speed Civil

Transport (HSCT) aircraft in the commercial fleet in the beginning of thetwenty-first century. NASA sponsored HSCT enabling

studies currently underway with airframers and engine manufacturers, are addressing a broad range of technical, environmental,

economic and related issues. Supersonic cruise speeds for these aircraft were originally focused in the Mach 2 to 5 range. At these

flight speeds, both jet fuels and liquid methane were considered potential fuel candidates. Subsequent analyses have led to further

definition of flight speeds and fuel candidates. For the year 2000 to 2010, cruise Mach numbers of 2 to 3 + are projected for aircraft

fuel with thermally stable liquid jet fuels. For 2015 and beyond, liquid methane fueled aircraft cruising at Mach numbers of 4+ may

be viable candidates. Operation at supersonic speeds will be much more severe than those encountered at subsonic flight. One of the

most critical problems is the potential deterioration of the fuel due to the high temperature environment. HSCT fuels will not only be

required to provide the energy necessary for flight, but will also be subject to aerodynamic heating and, will be required to serve as

the primary heat sink for cooling the engine and airframe. To define fuel problems for high speed flight, a fuels workshop was

conducted at the NASA Lewis Research Center during October 14 and 15, 1987. The purpose of the workshop was to gather experts

on aviation fuels, airframe fuel systems, airport infrastructure, and combustion systems to discuss high speed fuel alternatives, fuel

supply scenarios, increased thermal stability approaches and measurements, safety considerations, and to provide directional guidance

for future R&D efforts. Subsequent follow-up studies defined airport infrastructure impacts of high speed fuel candidaies. This paper

summarizes the results of these activities. In addition, an initial case study using a modified in-house refinery simulation model

Gordian code (I) is briefly discussed. Thi_ _ode can be used to simulate different types of refineries, emphasizing jet fuel production

and relative cost factors. \A_,_ _ ' =_ : "-

17. Key Words (Suggested by Author(s))

High speed commercial transports fuels consideration

18. Distribution Statement

Unclassified- Unlimited

Subject Category 28

19. Security Classif. (of this report)

Unclassified 20. Security Classif. Unclassified (of this page)

21. No. of pages

10

22. Price*

A02

NASAFORM1626OCT86 *For sale by the National Technical Information Service, Springfield, Virginia 22161