4/17/2017
`
`Patent U8265W86 - Method of operatingjet engines with fuel reforming - Google Patents
`
`Google
`
`us. Patent No. 2,655,786
`
`Patents
`
`Method of operating jet engines with fuel
`reforming
`US 2655786 A
`
`ABSTRACT available in
`
`IMAGES (2)
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`o 6
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`m ov
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`Puma,“ numb“
`Publication type
`Publication date
`Filing date
`Priority date (D
`.nmms
`Original Assignee
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`[Emma A
`Grant
`Oct 20, 1953
`Sep18,1950
`Sep 18. 1950
`Ca" Donald E
`Phillips Petroleum Co
`
`Export Citation
`
`BiBTeX, EndNote, RefMan
`
`Patent Citations (3), Referenced by (82), Classifications (16)
`External Links: USPTO, USPTO Assignment, Espacenet
`
`DESCRIPTION (OCR text may contain enors)
`
`CLAIMS avai|ab|e in
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`Oct. 20, 1953 o. E. CAM 2,655 786
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`METHOD OF OPERATING JET ENGINES WITH FUEL REFORMING Filed Sept. 18, 1950 2 Sheets-Sheet 1 9 TO
`AFTER BURNER COMBUSTION CHAMBER SUPPLY SUPPLY ,5 COMBUSTION A CHAMBER SUPPLY FIG. 3. r15. 4.
`
`INVENTOR. D. E.CARR
`
`A T TORNE Y5 Oct. 20, 1953 D. E. CARR 2,655 786
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`METHOD OF OPERATING JET ENGINES WITH FUEL REFORMING Filed Sept. 18, 1950 2 Sheets-Sheet 2
`COMBUSTION CHAMBER AIR: 33 32 SUPPLY FIGS.
`
`COMBUSTION CHAMBER INVENTOR. D. E. CARR A TTORNE Y5 Patented Oct. 20, 1953 UNITED STATES PATENT
`METHOD OF OPERATING JET ENGINES WITH FUEL REFORMING Donald E.- Carr, Bartlesville, Okla... assigtor to
`Phillips Petroleum Company, a corporation of Delaware Application September 18, 1950, Serial No. 185,417
`
`Cla'ms. 1
`
`This invention relates to Jet eng‘nes. In one of its more specific aspects, it relates to a method for providing a superior fuel
`composition for jet eng'nes. In another of its more specific aspects, it relates to the operaticn of continuous flow jet eng'nes.
`In another of its more specific aspects, it relates to the operation of jet engines while reforming a portion of a hydrocarbon
`fuel therefor.
`
`Jet eng'nes have only in the last few years been used in large numbers for the purpose of propelling aircraft and they have
`been found to be higily advantageous for use in high speed planes. With the increase in use of such eng'nes, however, a
`multitude of operational problems have also come to be recognized.
`
`A jet engine comprises three genera parts; first, an air intake section; second, a fuel addition and combustion section; and
`third, an exhaust section. The air intake section and meais for effecting such air intake is rougrly divided into three classes,
`i. e, the type found in a ram jet, a pulse jet, and a jet engine employing a. rotating compressor, such as a turbine
`compressor operated by a gas turbine, as motivating power for introducing the air into the combustion section. These
`different types of air intake systems, thougi substantially different in mechanical form, all serve the same function in each
`engine, namely, providing the necessary air supply to the combustion section. The combustion section, including the fuel
`injection system and the exhaust system, are somewhat similar in each type of engine. The purpose of operation of each of
`the eng'ne types is similar, namely, to bun the fuel and to utilize as much as possible of the heat energy added in producing
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`Patent U8265?86 - Method of operatingjet engines with fuel reforming - Google Patents
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`which utilizes part of the heat energy of the combustion gases in driving the air compressor so as to furnish additional air for
`the combustion zone. The gases then are exhausted to the atmosphere through the exhaust section or tail pipe with a
`concomitant production of thrust. In the case of the ram jet and pulse jet engines, the hot gases pass directly from the
`combustion section to the exhaust or tail pipe section and it is thus more difficult to establish as clear a line of demarcation
`between the zones of such engines.
`
`The general trend of thought concerning the operation of jet eng'nes has been that hydrocarbons do not vary sufliciently in
`their buning chaacteristics to make a material difference in the operation of any given jet engine. For that reason emphasis
`has for some time been placed on engine research so as to determine the design of a jet engine which would have such a
`struc— ture as would overcome the multitude of operational difficulties which ae inherently encountered in jet engines. Such
`operational difllcul ties have to date been only partially overcome b eng'ne design.
`
`Some of the problems wtich are encountered in the operation of such jet engines ae exemplified by those encourtered in a
`turbo-jet eng’ne. Performance of a jet engine is dependent to a large extent won the "temperature rise which is obtainable in
`the particular engine. Temperature rise is that increase in temperature between the inlet to the combustor and the
`temperature of the gases at the combustor exhaust outlet. In a turbo-jet engine, the temperature rise must be carefully
`controlled for the operation of a turbo-jet engine is limited by the ability of the turbine blades to withstand high temperatures.
`Fuel which is supplied to the combustor is bumed in the presence of stpplied air and raises the temperature of the
`combustion gases and unused air by the heat of combustion. An excess of air is conventionally utilized in the operation of
`turbojet engines to control the temperature of the gases contacting the turbine blades. Such a large quantity of air is utilized
`in the opera tion of jet engines that the air flow reaches very high velocities. The high air velocities pose many additional
`problems in the operation of jet engines, which problems are very difiicult to overcome. The hot gases are expanded and in
`the turbo-jet eng'ne are expanded through the tubine section which provides power for the compressor. Further expansion of
`the gases in a turbejet engine, as well as in a ram jet or pulse jet eng'ne, takes place in a rearwadly extending exhaust
`nozzle to provide a substantial increase in gas velocity. The thrust which is produced by the engine equals the gas mass
`flowing througi the exhaust duct times its increase in speed according to the law of momentum.
`
`For each engine speed at a given altitude, a certain temperature rise is required for the operation of any g'ven jet engine.
`Combustor inlet pressure and mass airflow through the engine imposes a limitation upon the combustion of any fuel utilized
`in the operation of the engine. For each combination of combustor inlet pressure and mass air flow there exists for any given
`fuel a maximum attainable temperature rise which depends won the combustor stability performance of that fuel under the
`combination of these conditions. As the operating conditions become more severe, a decrease in combustion stability is
`encountered. One phenomenon which tends to affect temperature rise in any given eng'ne is known as cycling. Cycling is
`an indication of instability of combustion of a given fuel. The flame front within the combustor tends 3 to fluctuate backand
`forth and many times the instability reaches such a degee that the flane is finally extinguished. The point at which
`combustion will no longer be sustained is known as the blowout or cutout point. Rich mixture blowout is the primary
`controlling characteristic of turbojet engine performance since it defines the maximum thrust output at a given altitude.
`When the temperature rise required' at a given engine speed and at a g'ven altitude corresponds to the maximum
`temperatue rise obtainable with a given fuel, a very definite operational limit is imposed upon that jet engine when operating
`with that specific fuel. In order to operate the engine under more severe operating conditions, it is necessary therefore to
`obtain and use a fuel which has stable combustion characteristics over a broader range of conditions than the fuel with
`which the maximum limit of operation has been reached. Simila operational problems are encountered in pulse jet and ran
`jet engines.
`
`' It has been found that many of the operational problems of such jet engines are overcome to a large extent when those
`engines are operated with a particular hydrocarbon fuel. Hydrocarbon fuels, contrary to general belief, burn differently mder
`different operating condtions. It will thus be seen that although stress has been placed won research for mechanical design
`of jet engines, a further limitation is placed upon the individual eng'nes by the particular fuel being utilized. A desirable jet
`engine fuel should be readily bumable and should facilitate maintenance of the flame in the combustion zone. The fuel
`shodd also produce a high thrust for each unit volume burned aid should not cause dfiiculty such as fouling the eng‘ne or
`fuel injection system.
`
`Hydrocarbon fuels which satisfactorily meet the above requ'rernents should be rated in an order of desirability by their ability
`to impat heat to air entering the combustion zone while maintaining stable combustion therein. Fuels may be rated generally
`in their order of desirability by operating a particular burner under a particular set of operating conditions which include
`combustion zone inlet air temperature, mass rate of air flow, and constant outlet pressure. An increase in the rate of fuel
`addition, when the above conditions are fixed, increases the temperature rise of the air in the combustion zone up to a
`critical point and after that point has been reached any increase in fuel addition results in decreasing the temperature of the
`combustion gases. A comparision of the maximum temperature rise (ATm) with the ATm obtained with two standard fuels,
`normal heptane and 2,2,4—trimethylpentane (isooctane) obtained in the same buner and under the same operating conditions
`make possible the rating of the tested fuel under such operating conditions. Assigring n-heptane and isooctane arbitrary
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`https:llwww.google.comlpatentslU32655786?dq=U.S.+Patent+No.+2,655,'/86&li=en&sa=x&ved=OahUKEinl-mhazTAhUDOZMKHaTflDjSQfiAEIIZAA
`UTC-2008.002
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`ATm,fATm,o
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`Patent US265586 - Method of operatingjet engines with fuel reforming - Google Patents
`
`where =Combustion stability rating ATm,f=Maximum stable temperature rise of the test fuel at the test conditions
`ATm,o=Maximum stable temperature rise of isooctane at the test conditions ATm,n=Maximum stable temperature rise of
`nheptane at the test conditions Quantitively there is no known correlation between flame speed and combustion stability.
`Qualitatively, however, an increase in flame speed resdts in an increase in combustion stability, other factors affecting
`combustion, such as fuel distribution, combustion design, etc., being equal.
`
`I have conceived a method of operating a jet engine with a singe fuel which includes the step of materially increasing the
`flame speed of the fuel which is introduced into the combustion zone over that possessed by the original fuel. This increase
`in flame speed of the fuel provides a considerably better combustion stability to the fuel introduced into the combustion zone
`than is possessed by the orig'nal fuel before being subjected to my method of engine operation.
`
`Best operation of turboiet eng'nes is obtained by introduction of a portion of the fuel into what is known as an afterbumer In
`a sense an afterbumer can be regarded as a ramjet connected to the downstream end of an ordinary turbojet. Aflerbumers
`operate at a lower oxygen content than the primary combustion zones of such engines. Under such conditions blow-out is
`one of the serious problems encountered therein. By my method of jet engine operation flame speed obtained within the
`afterbumer is increased with a resulting increase in combustion stability therein.
`
`Broadly speaking, this invention comprises an improved method for the operation of jet engines so as to provide a means of
`increasing the flame speed of the combustible mixture introduced into the combustion zone. This method of operation
`comprises the steps of reforming at least a portion of a selected hydrocabon fuel in the presence of a deficiency of oxygen
`compared to that which is requ'red for complete combustion, thus forming a mixture containing a substaitial amount of
`hydrogen. The mixture resulting from the reformation of the hydrocarbon fuel is added to the rema'ning dr and fuel in the
`combustion zone and the total fuel mixture is burned in the combustion zone. The presence of the hydrogen in the
`combustible mixture substantially increases the overall fuel flame speed and thereby decreases proportionater the volume
`of the combustion zone required by the engine.
`
`An object of this invention is to provide an improved method for operating jet engines. Another object of the invention is to
`provide an improved method for operating pulse jet engines. Another object of the invention is to provide an improved
`method for operating turbojet engines. Another object of the invention is to provide an improved method for operating ram jet
`engines. Another object of the invention is to provide a method of operating jet engines by which at lmt a portion of the
`hydrocarbon fuel is reformed to form a fuel mixture containing a substantial amount of hydrogen. Another object of the
`invention is to provide a method of operating jet eng’nes by which many of the inherent defects of operation are obviated.
`Another object of the invention is to provide a jet engine fuel which has highly desirable flame propagation character- 1st1cs.
`Other aid further objects and advantages will be mparent to those skilled in the art upon study of the accompanying
`disclosure.
`
`The reforming of the hydrocarbon fuel for ajet engine may be effected either thermally or catalytically duing operation of that
`engine. The hydrocarbon fuel to be reformed is preferably mixed with air in such a proportion that the oxygen present in the
`mixture i an amount equivalent to at least 0.6 mol and preferably not more than 1.0 mol per atom of carbon. In all instaices
`the amount of air which is used in the fuel reformation is less than that theoretically required for complete combustion. By
`this reforming, the hydrocarbon is converted to a mixture comprising a substantial amount of hydrogen which has an intrinsic
`flame speed much higher by comparison than the original hydrocarbon fuel. By conducting the fuel reformation within the
`above limits of oxygen, the predominant reaction is that of the conversion of carbon to an oxide of carbon, nanely carbon
`monoxide, and the formation of molecular hydrogen.
`
`When it is desired to catdytically reform the fuel, nickel is a preferred catalyst therefor. A catalyst su'table for reforming the
`hydrocarbon fuel may be formed, for example, by spraying aqueous nickel nitrate on a support, such as punice, heating the
`impregnated pumice to decompose the nickel nitrate to nickel oxide, and subseqrently reducing the nickel oxide to nickel.
`The catalyst so produced is then placed in a reforming zone of the jet engine and the reforming reaction is carried out over it.
`Other reforming catalysts, such as iron or alunina, may be utilized in the reformer chamber. Regeneration of the catalyst is
`satisfactorily obtained by shutting off theflow of hydrocarbon feed to the reformer chamber and subjecting the catalyst to a
`flow of oxygen.
`
`The reforming reactors ar preferably made of stainless steels such as 138 or 2520 steels, or other materials which can
`withstand the elevated temperatures sufficiently to offer a reasonable length of useful life. Temperatures of 1860" R to 2400
`R are used in the reforming zone when a catalyst is present, and in the absence of a catalyst, temperatures in the range of
`2460 R to 3000 R are utilized. Higher temperatures may be used in each instance, however. Inasmuch as the greatest
`possible temperature rise through the length of thejet engine is desired, catalytic reformation of the fuel at the lower
`temperatue is desired. The actual temperature at which the fuel reformation is accomplished is dependent upon the fuel
`throughput, length of the reforming chamber and amount of heat exchange which the returning chamber has with a cooling
`atmos u
`A
`- such as the sunoundin air.
`
` Try the new Google Patents, with machine-classified Google Scholar results, and Japanese and South Korean patents. IL"
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`Patent US265586 - Method of operatingjet engines with fuel reforming - Google Patents
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`Better understanding of the invention will be obtained upon study of the attached drawings in which Figure 1 is a
`diagrammatic sectional elevation of a combustion chamber and reforming chamber of a jet engine, together with a flow
`diagram showing a preferred fuel supply system for the jet engine. Figure 2 is a cross—section tdren at the line 22 of Figure
`1. Figure 3 is a modified sectional elevation of a combustion chamber and reforming chanber of a jet engine, together with a
`portion of a fuel system flow diagam therefor. Figure 4 is a vertical crosssection taken at line 4-4 of Figure 3. Figure 5 is a
`sectional elevation of another combustion chamber and reforming chamber of a jet engine, together with a portion of a fuel
`system flow diagram therefor. Figure 6 is a cross-section view taken at the line 6-6 of Figue 5. Figure 7 is a sectional
`elevation of an afterbumer chamber, together with a reforming chamber and a portion of a fuel system flow diagam for a jet
`engine.
`
`Referring partictlarty to Figue 1 of the drawings, air is supplied to the combustion chamber through the air intake portion of
`the jet engine. A stream of air is diverted through conduit II and pressurizing means, such as pump 12, to carburetor l3.
`Hydrocarbon fuel, such as kerosene, normal paraffins, aromatics and/or other hydrocarbon fractions, is supplied from a fuel
`tank It through conduit l5 and pump Hi to the forward portion of the combustion chamber. A portion of the fuel is diverted
`from conduit l5 througi conduit [1 to carburetor l3 and is sprayed into the air within the carburetor. Carburetor l3 may be
`heated to effect vaporization if so desired, but this is not a necessary feature of the invention. The fuelair mixture is
`removed from carburetor I3 through conduit IB and is passed through flane arrestor I9 to inlet manifold 21 of reformer
`chamber 22. If the fuel reforming is to be obtained in contact with a catalyst 20, the catalyst such as the one described
`above is provided within refomier chamber 22. Reformer chamber 22 sumounds a portion of the combustion chamber and is
`in indirect heat exchange therewith. The reformer chamber as shown is an annular chamber surrounding the combustion
`chamber. It may be a plurality of parallel tubes extending between two headers or it may be a single or a plurality of helical
`tubes extending about the combustion chamber. If ttierrnal reforming is to be utilized, reformer chamber 22 is ordinarily
`unrestricted throughout its entire lengh. Reformer chamber 22 encompasses a portion of the length of the combustion
`chamber and obtains heat reqdred for reformation of the fuel within chanber 22 by indirect heat exchange with the
`combustion chamber,
`
`The hydrocarbon fuel is reformed within the returning chamber to form a mixture whcih is high in hydrogen content. The
`resulting reformed fuet mixture from the reforming chamber is collected in outlet manifold 23 of reformer chamber 22 and is
`passed by means of conduit 24 into the forward portion of the combustion chamber, together with the unreformed fuel
`portion. The composite fuel mixtue is bunied in the combustion chamber and stbsequentty passes to the power producing
`zone, not shown. In this embodiment of the invention, the total arriount of a'r and fuel is substantially the same as that
`normally used in the operation of jet eng'nes. A large difference between this operation and the one normally used for
`conventional jet engines is that, because of the reformation of a part of the fuel the volume of combustion chamber 25 may
`be considerably smaller than is normally requ'red for conventional jet engines. Other differences are found in at least a patial
`overcoming of iriierent defects of operation of jet engines for the reason that the reformed fuel has a much higier flame
`speed than do conventiond hydrocabon fuels.
`
`In one modification of the above embodiment of the invention wherein the jet engine is a turbojet, a portion or all of the
`reformed fuet mixture is diverted from conduit 24 through conduit 9 to a secondary combustion chamber better known as an
`afterbumer section where it is used as fuel to add energy to the gases obtained from the turbine and prior to the exhaust of
`those gases fiom the exhaust nozzle.
`
`In Figure 3 of the drawings, air and fuel are supplied to the combustion chamber and reformer chamber in the same manner
`as disclosed in connection with the discussion of Figure 1 above. The fuel-air mixture which is obtained in the carburetor is
`introduced through line I8 into reformer chanber 28. Although a single reformer chamber section is shown in Figure 3 of the
`,high combustion temperatures.
`
`accuse drawings, additional reformer chamber sections may be provided at and spaced diout the periphery of combustion
`chamber 25 as shown by chambers dotted in in Figure 4 of the drawings. The resulting reformed fuel mixture is removed
`from reformer chamber 20 through conduit 20 and is introduced into the forward portion of the combustion chamber 25
`through inlet nozzles, together with the portion of unreforrned fuel material. When additional reformer chamber sections are
`required such as those shown in Figure 4 of the drawings, it will be desirable to connect those reformer chamber sections by
`manifold means at their inlet and outlet ends.
`
`Figure shows a section of a jet engine which differs from that shown in Figure 3 of the drawings by the rernovd of the
`reformer chanber sections from a position such that they contact the outer surface of the combustion chamber. This
`modification of the jet engine has the advantage of allowing the confining surface of the combustion chanber 25 to be
`cooled, for example, by an ambient air stream, without interfering with the operation of the reformer chamber sections. It will
`thus be apparent that greater efliciency is obtained in maintaining the reformer chamber sections at higi temperatures while
`maintaining fewer parts of the Jet engine at the The operation of the Jet engine shown in Figure 5 of the drawings is similar
`to that described in connection with Figures 1 and 3 of the drawings. The desired fuel-air mixture is introduced by means of
`conduit l8 into inlet header memberfl and is passed through reformer chamber sections 32 to outlet header 33. The resulting
`
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`reformed fuel mixture is introduced into the forward portion of the combustion chamber througi conduit 34 concomitant with
`the introduction of the hydrocarbon fuel thereinto through conduit I5.
`
`In Figure '7 of the drawings, a morified portion of a jet engine is shown such as is used in a turboJet engine. As pointed out
`above, it is desirable to maintain the turbine blades at as low a temperature as possibte while producing the energy required
`by expansion of the fuel. Thus a portion of the fuel is conventionally introduced into an afterburner section of the jet eng'ne
`where further expansion is obtained to produce an additiond amount of thmst for the engine.
`
`In the device shown in Figure 7 of the drawings, combustion gases from the primary combustion zone are directed by errg‘ne
`housing 35 and shaft housing 38 against turbine blades 36, these blades being connected to turbine wheel 31 which is in
`turn connected to a shaft which transmits power to an axial flow compressor, not shown. The gases leaving the turbine
`blades pass downstream over hub 39 and into the afterburner chamber portion. A fuel-air mixture similar to that described in
`connection with Figures 1, 3, and 5 is introduced througr condrit l8 into inlet manifold 4| and the mixture is reformed in
`reformer chamber sections 42 and is thereafter collected in outlet manifold 43 and supplied to the afterburner section,
`together with unreformed fuel stpplied to the afterburner section through conduit 44. The unreformed and reformed fuel
`materials are supplied to the afterburner section upstream of or adjacent to a suitable flame holder 45, which elements are
`well known in the jet engine art, and burn in the afterburner chamber 46. The combustion gases pass from this afterburner
`chamber to a thrust producing nozzle, not shown. The reforming chamber sections, as
`
`shown in Figue '7 of the drawings, are in contact with the hot gases in the combustion chamber of the afterbumer section
`and are thus maintained at suitable conditions of temperature for producing the reformed fuel.
`
`The amount of hydrocabon fuel which is reformed is dependent, generally, rpon the hydrogen content desired in the total
`fuel mixture. As little as 1 mol per cent of hydrogen, based upon the total fuel, has a beneficial effect in increasing the
`overall flame velocity of that fuel. It is desired to reform a sufficient amount of the hydrocarbon fuel to provide between 1 and
`700 mol per cent of hydrogen based on the original fuel.
`
`Continuous flow type jet engines are operated when the fuels discussed hereinabove are supplied to a given engine at a
`fuel-air ratio ranging between 0.005 and 0.10. A turbojet engine is operated at a fuel-air ratio within the range of 0.005 to
`0.040, preferably between 0.01 to 0.03. A ram jet engine operates at a fuel-air ratio ranging between 0.01 aid 0.10,
`preferably between 0.03 and 0.07. It is within the scope of this invention to operate thejet engine with the fuel described
`above and with the injection of oxygen. If oxygen or an oxygen-supplying compound, such as peroxide, is used for the
`purpose of supplying oxygen rather than air, the fuel-air ratio would necessarily have to be adjusted accordingly so as to
`maintain a fuel-oxygen ratio equivalent to the fuel-air ratio disclosed herein. Air is supplied to such jet engines at a
`combustor inlet air pressure of between 0.2 to 40 atmospheres at a mach nunber ranging between 0.01 and 1.0. Mach
`number is defined as the ratio of the velocity of a gas to the local velocity of somd in the gas. A turbo-jet combustor is
`operated at an inlet air pressure between 0.2 and 30 atmospheres, prefermly between 0.5 and 10 atmospheres at a mach
`number between 0.01 and 0.80, preferably between 0.02 and 0.30. A ram jet engine operates at an inlet air pressure of
`between 0.5 and 40 atmospheres, preferably between 1 and 10 atmospheres and at a mach nimber between 0.1 and 1.0,
`preferably between 0.3 and 1.0. Fuel is supplied to the combustor of such jet engines at a temperature ranging between 400
`'R and 700 R. The gas turbine has a preferred fuel inlet temperature of between 500 R and 560 R while the ram jet engine
`has a preferred fuel inlet temperature of between 500 R and 550 R. Air which is supplied to the combustor is preferably
`srpplied at a temperature between 430 R and 1500 R. The turbo-jet engine is operated at an inlet air temperature between
`430 R and 1200 R, preferably between 550 R and 900 R. A ram jet eng'ne operates at an inlet air temperature between 500
`R and 1500 R, preferably between 600 R and 1000 R. When operating these engines within the above range of conditions,
`the jet engine fuel of this invention buns within a combustion efliciency range of between 40 per cent and 100 per cent. and
`ordinarily within the range of from per cent to per cent. The exact fuel-air ratio which is utilizedis dependent upon eng'ne
`design limitations, such as turbine durability and the like. Fuel injection temperatures are dependent rpon fuel characteristics
`such as freezing point and volatility characteristics, as well as upon injection nozzle characteristics.
`
`Pulse jet engines ae operated with the greatest efliciency when the fuels dscussed hereinbefore are srpplied to a given
`engine at fuel-air ratios ranging between 0.01 and 0.08. It is preferred to operate such at engine while maintaining the fuel-a'r
`ratio'ranging between 0.03 and 0.07. Much difficulty is encountered in attempting to msure the exact amount of air actudly
`srpplied to a pulse jet engine because of the fact that up to about 30 per cent by volume of air may enter the combustion
`zone though the exhaust zone. A given pulse jet engine may be operated in a range of between 30 and iUO cycles per
`second, depending rpon the size of the eng'ne. By the term cycle," I mean to include fuel-air inlet, combustion, aid exhaust.
`Operation of a pulse jet engine under the above conditions re sults in a temperature rise" which may range from about 800 R
`to about 4500 R.
`
`I have disclosed my invention heretofore as mplied to the general use of a hydrocarbon fuel, such as kerosene, normal
`parafi'ins, aromatics, and other hydrocarbon fractions. The best operation a pertains to the reforming step will be obtained
`rpon utilization of a fuel having a high hydrogen to carbon ratio. Parafiinic-type materials are particularty well adapted to this
`
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`Patent US265W86 - Method of operatingjet engines with fuel reforming - Google Patents
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`which is predominantly parfiinic, but when the major portion of the fuel is alornatic it is at times prefened to utilize a
`sepaate pald'lin fuel portion for the purpose of reforming. In such operation, the resulting reformed fuel mixture is introduced
`into the combustion chamber together with the unrefonned fuel portion as has been discussed hereinbefore The
`hydrocarbon fuel which is utilized in my method of operating jet engines preferably boils within the range of between 550 R
`and 960 R, The predominantly parafiinic fuel portion which is subjected to the leforrning step of this invention is also
`preferably one which boils wittin this temperature range
`
`Many other modifications of this invention will be went to those skilled in the art upon study of the accompanying
`disclosure and drawings. These modifications will be obvious and are believed to be within the spirit and the scope of this
`disclosure.
`
`I claim:
`
`1. An improved method for operating a jet engine which comprises in combination the steps of passing a hydrocabon fuel
`portion together with air in an anount less than that theoretically required for complete combustion of that fuel portion
`through a reformer zone in indirect heat exchange with hot gases passing througl said jet engine and under such condtions
`of temperature as to reform said hydrocarbon fuel to form a fuel mixture consisting essentially of carbon monoxide and
`hydrogen; introducing an unreforrned fuel portion into the forward portion of a primary combustion zone of said jet engine;
`intro ducing said reformed fuel mixture into a gas stream within a combustion zone in said jet eng'ne; burning said
`unrefomred fuel portion and said fuel mixtue in the preserlce of air in said jet engine so as to obtain a sufficient temperature
`rise through said jet engine to provide motivating thrust to said jet engine by rearward exhaust of hot gases therefrom.
`
`2. An improved method for operating a jet engine which comprises in combination the steps of passing a hydrocabon fuel
`together with air in an amount within the range of 0.6 mol to 1.0 mol per atom of carbon in that fuel portion througr a reformer
`zone in indirect heat exchange with hot gases passing though said jet engine and under such conditions of temperature as
`to reform said hydrocarbon fuel to form a fuel mixture consisting essentially of carbon monoxide and hydroge