Fuel supply system, scramjet engine and method for operating the same

In order to stably use a catalyst for pyrolysis and supply a reformed fuel, the fuel supply system includes a fuel reforming section which pyrolyzes a hydrocarbon system fuel by the heat of the combustion chamber to generate the reformed fuel. The fuel reforming section includes a preheat vaporization section provided on the combustion chamber, and a decomposition reaction section that is provided on the preheat vaporization section and includes the catalyst for pyrolysis. The preheat vaporization section heats the fuel, the decomposition reaction section pyrolyzes the heated fuel to generate the reformed fuel, and the fuel reforming section supplies the reformed fuel to the combustion chamber. The reforming catalyst includes a zeolitic catalyst.

INCORPORATION BY REFERENCE

This patent application claims a priority on convention based on Japanese Patent Application No. 2013-015092. The disclosure thereof is incorporated herein by reference.

TECHNICAL FIELD

The present invention rerates to a scramjet engine which generates a driving force by supersonic combustion, and particularly to a fuel supply system of the scramjet engine.

BACKGROUND ART

In order to stabilize supersonic combustion using a fuel of hydrocarbon system, it is desirable to increase a rate of hydrocarbon with small carbon number in a fuel, and keep a distribution of the carbon number constant in the fuel. Also, since the hydrocarbon with small carbon number is a gas state at normal temperature, when the hydrocarbon with small carbon number is mounted on a fuel tank, Fuel on Board cannot be increased and supersonic combustion (supersonic flight) cannot be realized for long periods of time. Therefore, it is considered to mount hydrocarbon with large carbon number as a main component, which is liquid at normal temperature, on the fuel tank, and decompose the liquid hydrocarbon fuel by heat of an engine during a flight for obtaining a reformed fuel that includes hydrocarbon with small carbon number as a main component.

Patent literature 1 discloses a heat management system of a propulsion engine for a supersonic and hypersonic aircraft. The system uses a single flow of endothermic fluid as a fuel and a heatsink for cooling the engine. The system includes a plurality of heat exchanger arranged in series. Each heat exchanger includes a reaction section having a catalyst so as to exchange heat with a heat source section. The single flow of fluid flows through each of the reaction section and the heat source section. Heat for a reaction in the reaction section is given from fluid in the heat source section, and thereby the fluid is cooled. This cooled fluid is heated again when flowing through a hot section of the engine, and flows toward other reaction section or flows toward a combustor of the engine to be fired.

Patent literature 2 discloses a method of enhancing combustion speed to expand a limit of an accidental fire in a high-speed propulsion unit such as a ramjet and scramjet engine. A flow of a hydrocarbon system fuel is decomposed by a catalyst to generate hydrogen and a fuel resolvent of low-molecular weight. The hydrogen and the fuel resolvent of low-molecular weight are introduced into a combustor of the high-speed propulsion unit with a flow of the hydrocarbon system fuel which is not decomposed. According to this method, an operation range of the combustor expands, and a high combustion speed and an enhancement of flame stability are achieved by higher-speed diffusive mixing. This process effectively expands an operation limit of a gas turbine, especially of a ramjet and scramjet combustor.

Moreover, patent literature 2 discloses followings. The fuel is vaporized in a catalytic reaction section to be decomposed by catalysts into hydrogen and fuel resolvent of low-molecular weight. What type of fuel is generated depends on what type of fuel is introduced into the reaction section. Preferable catalysts used in the reaction section include platinum group metals such as platinum, rhodium, iridium, and palladium. It is indicated that catalysts including other metals such as nickel, chromium, and cobalt are also effective. The catalysts may be composed by a single metal, and may be composed by a combination of appropriate metals.

In a catalytic reaction, there is an effective temperature range for respective catalysts, and the catalytic reaction should be managed in this range. However, since a temperature of a combustion chamber of the scramjet engine is very high and is equal to or more than thousands degrees C., it is very difficult to control a temperature of the catalyst arranged near the combustion chamber to be a desired temperature by using a heat generated by the combustion chamber. When the heat supplied to a catalytic layer is excessive, there is a possibility that the temperature of the catalyst becomes too high, the catalyst is inactivated, heat decomposition becomes difficult, and generation of the reformed fuel becomes difficult. Furthermore, when a temperature of a catalytic reaction region is unstable, there is a possibility that fuels of liquid state and gas state are mixed, the catalyst is stripped from a flow channel by vaporization/bumping of fuels to block the flow channel, and supply of the reformed fuel becomes difficult.

CITATION LIST

DISCLOSURE OF INVENTION

An object of the present invention is to provide a fuel supply system, a scramjet engine and a method for operating the same, which are able to decompose a fuel by heat of a combustion chamber to generate a reformed fuel, and stably supply the reformed fuel when the reformed fuel is combusted in the combustion chamber, in a scramjet engine. Furthermore, another object of the present invention is to provide a fuel supply system, a scramjet engine and a method for operating the same, which are able to stably use the reformed fuel for heat decomposition in a scramjet engine. Further another object of the present invention is to provide a fuel supply system, a scramjet engine and a method for operating the same, which are able to enhance heat energy efficiency in a scramjet engine.

These objects, other objects, and effects of the present invention will be easily confirmed by the below explanation and attached drawings.

The fuel supply system according to the present invention includes a fuel reforming section configured to decompose a hydrocarbon system fuel by heat from a combustion chamber of a scramjet engine to generate a reformed fuel, and cool the combustion chamber. The combustion chamber includes a preheat vaporization section arranged on the combustion chamber, and a decomposition reaction section including a reforming catalyst for pyrolysis. The preheat vaporization section heats the fuel. The decomposition reaction section decomposes the heated fuel to generate a reformed fuel. The fuel reforming section supplies the reformed fuel to the combustion chamber. The reforming catalyst includes a zeolitic catalyst.

In the above-mentioned fuel supply system, the zeolitic catalyst may include H-ZSM-5 catalyst.

In the above-mentioned fuel supply system, the zeolitic catalyst may support platinum group elements.

In the above-mentioned fuel supply system, the reforming catalyst may further include an oxidized catalyst which supports platinum group elements.

In the above-mentioned fuel supply system, the fuel reforming section may further include an outside cooling section provided on the decomposition reaction section. The fuel may be supplied to the preheat vaporization section via the outside cooling section.

In the above-mentioned fuel supply system, a temperature of the decomposition reaction section may be equal to or more than 400° C. and less than 600° C.

In the above-mentioned fuel supply system, a cross-section of a flow channel of the preheat vaporization section may be a triangle, and its bottom side may contact an upper side of the combustion chamber. A cross-section of a flow channel of the decomposition section may be an inverted triangle, and its two lower sides may contact each of adjacent upper sides of adjacent two triangles of the preheat vaporization section.

In the above-mentioned fuel supply system, a cross-section of a flow channel of the preheat vaporization section may be a triangle, and its bottom side may contact an upper side of the combustion chamber. A cross-section of a flow channel of the decomposition section may be a diamond shape, and its bottom sides may contact each of adjacent upper sides of adjacent two triangles of the preheat vaporization section.

A scramjet engine according to the present invention includes an air compression section, an injector, a combustion chamber, and a fuel supply system. The air compression section compresses an air to generate a compressed air. The injector sprays a reformed fuel in the compressed air. In the combustion chamber, the reformed fuel is combusted. The fuel supply system is provided on the combustion chamber and described in either above paragraphs.

A method of operating scramjet engine according to the present invention is a method of operating a scramjet engine which includes an air compression section, an injector, a combustion chamber, and a fuel reforming section. The method includes: a step of compressing an air to generate a compressed air by the air compression section; a step of spraying a reformed fuel in the compressed air by the injector; a step of combusting the reformed fuel in the combustion chamber; and a step of decomposing a hydrocarbon system fuel by a heat of the combustion chamber and generating the reformed fuel to cool the combustion chamber, by the fuel reforming section. The step of generating the reformed fuel to cool the combustion chamber includes: a step of heating the fuel by a preheat vaporization section provided on the combustion chamber; and a step of generating the reformed fuel by decomposing a fuel that is heated in a decomposition reaction section that is provided on the preheat vaporization section and includes a reforming catalyst for pyrolysis.

According to the present invention, it is possible to stably supply a reformed fuel when heating and decomposing a fuel by the heat of the combustion chamber to generate the reformed fuel and combusting the reformed fuel at the combustion chamber of the scramjet engine. Also, according to the present invention, in the scramjet engine, a reforming catalyst for pyrolysis can be stably used. Further, according to the present invention, in the scramjet engine, heat energy efficiency can be enhanced.

DESCRIPTION OF EMBODIMENTS

Hereinafter, referring to the attached drawings, a fuel supply system, a scramjet engine and a method for operating the same according to the present embodiment will be explained.

Configurations of the fuel supply system and the scramjet engine according to the present embodiment will be described.FIG. 1is a schematic view showing a configuration example of an aircraft to which a scramjet engine according to this embodiment is applied. This aircraft includes an airframe10and a scramjet engine11included in the airframe10. The scramjet engine11is an engine which generates a driving force by supersonic combustion, and includes a compression section20, an injector30, a combustion chamber40, and a nozzle50. The air compression section20compresses air introduced from the outside and generates a compressed air to supply to the combustion chamber40. The injector30sprays a reformed fuel in an air current70of the compressed air, in the combustion chamber40. In the combustion chamber40, the reformed fuel is combusted. The nozzle50supplies combustion gas which is generated by combustion of the reformed fuel.

Here, the combustion chamber40becomes high temperature because the reformed fuel is combusted. Therefore, the combustion chamber40must be cooled to prevent damage of the combustion chamber40. On the other hand, for appropriate combustion in the combustion chamber40, it is necessary to pyrolyze a liquid fuel whose main component is hydrocarbon with large carbon number to generate the reformed fuel whose main component is hydrocarbon with small carbon number. In this embodiment, these requests are addressed by the following configuration of the scramjet engine.

FIG. 2AandFIG. 2Bare schematic block diagrams showing a configuration example of the scramjet engine according to the present embodiment.FIG. 2Ais a block diagram, andFIG. 2Bis a cross-section view ofFIG. 2Aalong XX. Moreover, the scramjet engine11includes a fuel supply system15. The fuel supply system15pyrolyzes a liquid fuel whose main component is hydrocarbon with large carbon number to generate the reformed fuel whose main component is hydrocarbon with small carbon number, and supplies them to the combustion chamber40. The fuel supply system15includes a fuel reforming section60, a fuel tank71, a flow rate adjustment valve76, an electronic control unit (ECU)77, and sensors80-83.

As shown inFIG. 2A, the fuel tank71has a liquid fuel (for example, jet fuel such as JetA-1 fuel) which includes hydrocarbon with large carbon number, as a main component. The fuel in the fuel tank71is supplied to the fuel reforming section60via a pipe72. The flow rate adjustment valve76is provided on the pipe72and adjusts an amount of fuel supplied to the fuel reforming section60under control of the ECU77. The fuel reforming section60pyrolyzes the liquid fuel by heat of the combustion chamber40to generate a gaseous reformed fuel. Since the pyrolyzing reaction is an endoergic reaction, the fuel reforming section60cools the combustion chamber40. Such cooling is sometimes called as regenerative cooling. The reformed fuel generated in the fuel reforming section60is supplied to the injector30through the pipe75. Details about the fuel reforming section60will be described later. The injector30sprays the reformed fuel in the air current of the compressed air, in the combustion chamber40. The reformed fuel is combusted in the combustion chamber40. The sensors80-82detect a situation of the fuel reforming section60. The sensor83detects a situation of the combustion chamber40. Each of sensors80-83includes at least one of a thermal flow rate sensor, a temperature sensor, a pressure sensor, and a flow rate sensor. The ECU77controls the flow rate adjustment valve76and the injector30or the like, based on the situation of the fuel reforming section60and the combustion chamber40(outputs of the sensors80-83). By controlling the flow rate adjustment valve76based on the situations of the fuel reforming section60and the combustion chamber40, an amount of fuel supplied to the fuel reforming section60is adjusted based on the situations of the fuel reforming section60and the combustion chamber40. Since there is a case that when an amount of the liquid fuel supplied to the fuel reforming section60fluctuates, an amount of the generated reformed fuel fluctuates, it is preferable that an amount of the reformed fuel sprayed by the injector30corresponds to the amount of the supplied fuel. Therefore, the ECU77controls the injector30to correspond to the control for the flow rate adjustment valve76.

The fuel reforming section60will be further explained. The fuel reforming section60vaporizes the liquid fuel primarily consisting of hydrocarbon with large carbon number by a heat of the combustion chamber40, reforms (pyrolyzes) it, and generates a gaseous reformed fuel primarily consisting of hydrocarbon having carbon number smaller than that of the fuel. The fuel reforming section60includes a preheat vaporization section63and a decomposition reaction section62, and preferably further includes an outside cooling section61.

The preheat vaporization section63is provided at a position which is the closest to the combustion chamber40in the fuel reforming section60, and exchanges heat with the combustion chamber40. That is, the preheat vaporization section63is received heat from the combustion chamber40, heats the liquid fuel flowing inside by the received heat, and generates a gaseous fuel. In other words, the liquid fuel flows an inside of the preheat vaporization section63, a state of the fuel is changed to gas from liquid, and the combustion chamber40is cooled by a sensible heat and evaporative latent heat of the fuel. Transformation of a state of the fuel from liquid to gas is preferable not only from a viewpoint of cooling but also from a viewpoint of setting a state of the fuel suitable for a catalytic reaction. Here, the preheat vaporization section63is preferably arranged on and contacts the combustion chamber40. It is because heats can be efficiently received from the combustion chamber40.

The decomposition reaction section62includes a catalyst65for pyrolysis (for reforming), is provided on the preheat vaporization section63, and exchanges heat with the preheat vaporization section63. That is, the heat is supplied to the decomposition reaction section62from the preheat vaporization section63, and the decomposition section62utilizes the heat and the catalysts65to pyrolyze the fuel flowing in the decomposition reaction section62and generate the reformed fuel. Especially, since the pyrolysis reaction of the fuel with the catalyst65is an endothermic reaction, the decomposition reaction section62consumes much heat from the preheat vaporization section63. Here, the heat supplied from the preheat vaporization section63can be considered as heat supplied from the combustion chamber40via the preheat vaporization section63. That is, the decomposition reaction section62cools the combustion chamber40by depriving much heat via the preheat vaporization section63by the pyrolysis reaction (the reforming reaction). In this time, it is preferable to arrange the preheat vaporization section63between the decomposition reaction section62and the combustion chamber40, from viewpoints of suppressing a rapid increase in temperature of the decomposition reaction section62to prevent deactivation of the catalyst, and easily obtaining a catalytic reaction temperature range (for example: from 400 degrees C. to 600 degrees C.) that is suitable for the catalytic reaction.

The outside cooling section61is provided on the decomposition reaction section62and exchanges heat with the decomposition reaction section62. That is, the heat is supplied to the outside cooling section61from the decomposition reaction section62, and the outside cooling section61utilizes the heat to heat the fuel flowing through its inside. In other words, the outside cooling section61utilizes the heat from the decomposition reaction section62for heating the liquid fuel to block the heat, and prevents heat from damaging electric devices (for example: ECU77) that are provided above the outside cooling section61.

The fuel (liquid) of tank71, which includes hydrocarbon with large carbon number as a main component, is supplied to the outside cooling section61through the pipe72while a flow rate is adjusted by the flow rate adjustment valve76. The fuel (liquid) is heated by the decomposition reaction section62in the outside cooling section61. After that, the heated fuel (liquid) is supplied to the preheat vaporization section63through the pipe73. The fuel (liquid) is heated by the heat of the combustion chamber40and becomes a gaseous fuel. After that, the heated fuel (gas) is supplied to the decomposition reaction section62through the pipe74. The fuel (gas) is heated by heat of the preheat vaporization section63, and is pyrolyzed by the catalyst65to become a reformed fuel (gas) that includes hydrocarbon with small carbon number as a main component. After that, the reformed fuel (gas) is supplied to the injector30through the pipe75.

A fuel channel of the fuel reforming section is provided to surround the combustion chamber40. In the example ofFIG. 2AandFIG. 2B, the fuel reforming section60is provided above the combustion chamber40. For example, specifically, the fuel channel of the fuel reforming section60is shown inFIG. 2B. A fuel channel of the preheat vaporization section63is provided on a top of the combustion chamber40. In this example, three fuel channels, each of which has a rectangular cross-section, are provided. At a top of the preheat vaporization section63, a fuel channel of the decomposition reaction section62is provided. In this case, six fuel channels, each of which has a rectangular cross-section, are provided. Then, two fuel channels of the decomposition reaction section62are provided on one of the fuel channels of the preheat vaporization section63. Catalysts65are provided in each fuel channel of the decomposition reaction section62. It is preferable that number of fuel channels per unit volume of the decomposition reaction section62is relatively large, since a surface area of an inner wall of the decomposition reaction section62can be relatively large. As a result, a surface area of the catalysts65can be relatively large, and a pyrolysis reaction can reliably proceed. At a top of the decomposition reaction section62, a fuel channel of the outside cooling section61is provided. In this case, three fuel channels, each of which has a rectangular cross-section, are provided. Then, one fuel channel of the outside cooling section61is provided on two fuel channels of the decomposition reaction section62. However, the number of fuel channels at each of above-mentioned parts is arbitrary, and may be more or less.

The decomposition reaction section62includes the catalyst65in its fuel channel. The catalyst65is illustrated by a catalyst65barranged on an inner wall of the fuel channel, and a catalyst65ahaving a grained shape or ring-shape arranged in the fuel channel. The catalyst65preferably includes: a zeolitic catalyst such as H-ZSM-5 catalyst; PGM (Platinum Group Metals: the platinum family) system catalyst such as platinum catalyst, palladium catalyst, and rhodium catalyst; and a catalyst including at least one of oxide catalysts having large surface area or a complex thereof. Among these, H-ZSM-5 catalyst has a high effect for promoting the above-mentioned pyrolysis. Therefore, it is preferable to include H-ZSM-5 catalyst as the catalyst65, from a viewpoint of decrease a size of the fuel reforming section60. Moreover, when the zeolitic catalyst supporting platinum group elements, an oxide system catalyst, or both of them is included as the catalyst65, the above-mentioned effect for promoting the pyrolysis becomes higher than in a case of separately arranging the PGM system catalyst and the zeolitic catalyst. Therefore, it is preferable to use these catalysts as the catalyst65from a viewpoint of further decreasing the size of the fuel reforming section60.

As mentioned above, the fuel reforming section60according to this embodiment includes fuel channels so that the preheat vaporization section63, the decomposition reaction section62, and the outside cooling section61surround the combustion chamber40. The outside cooling section61rises a temperature of the liquid fuel in the fuel channel, restrains a heat loss to an outside of the combustion chamber40by the sensible heat, relatively cools the outside, and prevents damages of the electric devices (for example: ECU77). The preheat vaporization section63changes the liquid fuel flowing in the fuel channel to the gaseous fuel, cools the combustion chamber40by the sensible heat and the evaporative latent heat, and puts a state of the fuel suitable for a catalytic reaction. Further, a rapid increase in temperature of the decomposition reaction section62is suppressed, deactivation of the catalyst is prevented, and a catalytic reaction temperature range (for example: 400 degrees C.˜600 degrees C.) is suitable for the catalytic reaction is formed. The decomposition reaction section62pyrolyzes the fuel flowing in the fuel channel by the catalyst65to generate the reformed fuel and cool the combustion chamber40by the endoergic reaction of the pyrolysis. As mentioned above, the fuel supply system15is considered as a regenerative cooling system, which effectively decomposes a carbon fuel with large carbon number into a carbon fuel with small carbon number to concurrently cool the combustion chamber40and the outside of the combustion chamber40.

Also when selecting the temperature of the combustion chamber40as a situation of the combustion chamber40to be managed (when sensor83detects the temperature of the combustion chamber40), the temperature of the combustion chamber40can be effectively managed by adjusting an amount of endotherm in the pyrolysis of the fuel.

FIG. 3is a graph indicating an example of a relation between a temperature and a state of the fuel, in the fuel supply system according to the present embodiment. The upper graph indicates one example of a relation between the temperature of the fuel (the vertical axis) and a position in the fuel supply system15(transverse). The downside graph indicates one example of a relation between the states of the fuel (A: liquid (hydrocarbon fuel), B: gas (hydrocarbon fuel), and C: decomposed hydrocarbon fuel (reformed fuel)) and the position in the fuel supply system15(transverse). The undermost draw is a schematic view showing positions in the fuel supply system shown in each graph, correlating withFIG. 2A.

In the fuel tank71, the temperature of the (hydrocarbon) fuel is low of T1, and its state is A: liquid. In the outside cooling section61, the temperature of the fuel does not increase so much to be about T1, and its state remains A: liquid. Here, a temperature of a component part (for example, a part including ECU77) arranged at the outside of the combustion chamber40(and the fuel reforming section60) becomes not so high because of a flow of the liquid fuel in the outside cooling section61, and is considered as about T1 that is almost equal to the temperature of the liquid fuel. After that, the liquid fuel is supplied to the preheat vaporization section63.

In the preheat vaporization section63, the temperature of fuel gradually rises by supply of heat from the combustion chamber40. In the example shown in this Figure, the temperature of the fuel rises to about T2 from about T1. Meanwhile, the liquid fuel is gradually vaporized by the supplied heat. Then, finally, the state of the fuel becomes state B: gas. On the other hand, the combustion chamber40is cooled by the sensible heat and the evaporative latent heat. After that, the gaseous fuel is supplied to the decomposition reaction section62. The Gaseous fuel is in the condition where the catalytic reaction is easy to be stably promoted.

In the decomposition reaction section62, a pyrolysis reaction occurs by the heat supplied from the preheat vaporization section63(the heat supplied from the combustion chamber40through the preheat vaporization section63) and the catalyst65. At this time, the temperature of the fuel is slightly decreased because of the endothermic reaction in the pyrolysis reaction and a heat loss to the outside cooling section61, and controlled to be a temperature suitable for the catalytic reaction (for example: T2˜T3). As described later, the temperature suitable for the catalytic reaction is illustrated by 400 degrees C.˜600 degrees C. when the catalyst65is the zeolitic catalyst (for example: H-ZSM-5 catalyst).

Next, a method of operating the scramjet engine11(FIG. 1,FIG. 2A, andFIG. 2B) according to the present embodiment will be explained.

For example, the method of operating scramjet engine11includes a first step to a fourth step. The first step is a step of compressing an air by the air compression section to generate a compressed air. The compressed air is supplied to the combustion chamber40. The second step is a step of spraying a reformed fuel in the compressed air of the combustion chamber40by the injector30. The third step is a step of combusting the reformed fuel in the combustion chamber40. The fourth step is a step of pyrolysing the hydrocarbon system fuel by the heat of the combustion chamber40at the fuel reforming section60to generate the reformed fuel, and cooling the combustion chamber.

Here, the fourth step, in which the fuel reforming section60generates the reformed fuel to cool the combustion chamber40, includes following fifth step and sixth step. The fifth step is a step of heating the fuel by the preheat vaporization section63provided on the combustion chamber40. The sixth step is a step of pyrolysing the heated fuel to generate the reformed fuel, by the decomposition reaction section that is provided on the preheat vaporization section63and includes the catalyst65for pyrolysis. Moreover, the fourth step may further include a step of heating the fuel by the outside cooling section61provided on the decomposition reaction section62to supply the fuel to the preheat vaporization section63.

By the above-mentioned method, the scramjet engine11according to the present embodiment is operated.

(Examination about the Catalyst Activated Temperature Range)

Next, examination was carried out for a temperature range in which the catalyst65stably promotes the catalytic reaction. Specifically, a change of decomposition amount of hydrocarbon was observed by changing a temperature of the catalytic layer, when a fuel including hydrocarbon with large carbon number as a main component is continuously leaded through a catalytic layer to be pyrolyzed into a fuel including hydrocarbon with small carbon number. Furthermore, it was confirmed whether or not a deposition of carbide existed, which decreases the catalytic reaction.

Here, the examination was carried out by using a decomposition reaction heat evaluation test.FIG. 4is a schematic view showing a configuration of the decomposition reaction heat evaluation test. A device for evaluating a reaction heat in the pyrolysis reaction of the fuel includes a reaction tube113, an H-ZSM-5 catalytic layer114, an electric furnace115, a thermocouple116, and a thermocouple protective tube117. The reaction pipe113has 17.3 mm of outside diameter, 12.7 mm of caliber, and 400 mm of length. Z-coordinate is defined along a line parallel to an axial direction of the reaction tube113. The reaction pipe113is arranged in the electric furnace115. The electric furnace115has 400 mm of length in the axial direction of the reaction tube113. The thermocouple116is arranged in the reaction tube113and protected by the thermocouple protective tube117. The thermocouple protective tube117has 4 mm of outside diameter, and 2 mm of caliber. Z-coordinate which is center of the reaction tube113is defined as 0 mm. A plurality of temperature measured points116aare set in a range from −145 mm to +145 mm in Z-coordinate of the reaction tube113. The H-ZSM-5 catalytic layer114is arranged at a center (Z coordinate: 0 mm) of the reaction tube113. The H-ZSM-5 catalytic layer114is supported by an eye plate and glass wool which is not shown. A thickness of the H-ZSM-5 catalytic layer114is 10 mm, and a quantity of catalyst is 1 g (1 cc). Reaction temperatures are 300° C., 450° C., and 600° C., and a reaction pressure is 0.9 MPa. Under the above-mentioned condition, a vaporized fuel120was continuously introduced into the reaction tube113for one hour for stabilizing the decomposition reaction. Then, the hydrocarbon fuel which had passed through the catalytic layer114was analyzed by a gas chromatography and a mass spectroscope. Moreover, the endothermic reaction of the catalytic layer114was measured with the thermocouple installed in the catalytic layer114. However, LHSV (Liquid Hourly Space Velocity=flow rate of fuel (cc/h)/the volume of the catalytic layer) is set to 200/h. As the fuel, dodecene and JetA-1 fuel were used.

FIGS. 5A to 5Care graphs showing measurement results at each reaction temperatures of dodecene (C12H24).FIG. 5Ashows a measurement result at 300° C.,FIG. 5Bshows a measurement result at 450° C. andFIG. 5Cshows a measurement result at 600° C. The vertical axis shows a rate (wt %) of a product, and the transverse shows a kind of the product.

As shown inFIG. 5A, at the reaction temperature of 300° C., molecules with large carbon number are hardly decomposed. C12inversion rate remains at 18.0 wt %. However, carbon deposits are hardly detected (<5 wt %). At the reaction temperature of 450° C., as shown inFIG. 5B, molecules with large carbon number is almost decomposed. Then, a number of molecules with small carbon number are generated, which is easily combusted at supersonic combustion. The C12inversion rate reaches at 89.4 wt %. Carbon deposits are hardly detected (<5 wt %). At the reaction temperature of 600° C., as shown inFIG. 5C, the decomposition of molecules with large carbon number is promoted, and a number of molecules with small carbon number are generated. The C12inversion rate reached at 96.4 wt %. However, a number of carbon deposits (solid body carbide) are deposited (36 wt %), and a caulking phenomenon occurs, which blocks the fuel channel.

Although there is not illustration, the Jp-4 fuel yields a result similar to the pyrolysis of dodecene. Also, the above result could be obtained not only for the zeolitic catalyst but also for the complex catalyst of the zeolitic catalyst and the PGM system catalyst.

According to the examination result of the above-mentioned catalyst activated temperature range, as a temperature range which causes a stable catalytic reaction, the following point was proved. That is, in order to activate the catalytic reaction, temperature equal to or more than 400° C. and less than 600° C. is appropriate when a zeolitic catalyst or a complex of zeolitic catalyst and PGM system catalyst is used. Controlling the temperature of the decomposition reaction section62to be in such temperature range, a desired pyrolysis reaction can be progressed.

For example, in the above-mentioned scramjet engine11, a method can be also considered, which uses only the decomposition reaction section62and does not use the preheat vaporization section63and the outside cooling section61. That is, it is a method in which only the decomposition reaction section is directly arranged on top of the combustion chamber40. In such a case, the following situation may be occurred. (1) Since the combustion chamber40is high temperature equal to or more than thousands of degrees C., the decomposition reaction section on the combustion chamber cannot be easily controlled, and the temperature of the decomposition reaction section may be rapidly increased. In this case, the catalyst is inactivated, and the fuel cannot be pyrolyzed. It is considered to keep a sufficient distance between the decomposition reaction section and the combustion chamber40as a countermeasure, but it is not appropriate because cooling of the combustion chamber40by the endothermic reaction of the decomposition reaction section becomes difficult. (2) Also, in the catalytic reaction, reactivity varies widely depending on whether the fuel to be reformed is liquid or gas. If it is liquid, high reactivity cannot be obtained since a contact frequency between the fuel and the catalyst is low. When the decomposition reaction section is arranged on the combustion chamber40, since the fuel in which liquid and gas is mixed contacts the catalyst, the reactivity becomes unstable, and the effective catalytic reaction cannot be obtained. Furthermore, the probability of catalyst being stripped from the flow channel by vaporization/bumping of the fuel or the like to block the flow channel becomes high.

However, according to the present embodiment, in the above-mentioned scramjet engine11, the preheat vaporization section63is arranged on the combustion chamber40, and the decomposition reaction section62is arranged on the preheat vaporization section63. That is, the heat of the combustion chamber40is supplied to the preheat vaporization section63at first, and supplied to the decomposition reaction section62after that. The fuel is supplied to the decomposition reaction section62via the preheat vaporization section63. Accordingly, the fuel to be supplied to the decomposition reaction section62can be previously changed to gas at the preheat vaporization section63. As a result, the occurrence of the above-mentioned situation (2) can be prevented. Also, since the preheat vaporization section63is provided between the decomposition reaction section62and the combustion chamber40, the heat of the combustion chamber40is not directly supplied to the decomposition reaction section62. As a result, the occurrence of the above-mentioned situation (1) can be prevented.

Moreover, in the above-mentioned scramjet engine11, when the outside cooling section61is arranged on the decomposition reaction section62, it is possible to prevent electronic devices or the like (for example: ECU77) arranged at the outside of the fuel reforming section60becomes excessively high temperature. As a result, malfunctions of these electronic devices can be prevented, and these electronic devices can carry out stable and appropriate control.

As mentioned above, according to the present embodiment, the pyrolysis reaction of the fuel using the catalytic can be stable, by changing the liquid fuel to the gas fuel and suppressing excessive heat flowing into the catalytic reaction area. As a result, molecules with small carbon number can be sufficiently generated, which is effective for efficient combustion. At the same time, the combustion chamber can be effectively cooled by using the endothermic of the pyrolysis reaction. Moreover, it can be suppressed that the heat transmits to the outside electronic devices, by providing the outside cooling section that pre-heats the fuel.

In the above-mentioned embodiment, the configuration of the fuel reforming section60on the combustion chamber40is not limited to the above-mentioned configuration. For example,FIGS. 6A to 6Dare schematic sectional views showing configurations of variation examples of the scramjet engine according to the present embodiment. These figures are sectional views of XX inFIG. 2A, and indicate the combustion chamber40and the fuel reforming section60of the fuel supply system15.

The explanation of the combustion chamber40and the fuel reforming section60in the example ofFIG. 6Awill be omitted since it is same asFIG. 2B.

In the example ofFIG. 6B, the fuel reforming section60is provided on the combustion chamber40. As shown inFIG. 6B, fuel channels of the preheat vaporization section63are provided on the top of the combustion chamber40. In the example of this Figure, six fuel channels each of which has a triangle cross-section are provided. The bottom line of the triangle contacts an upper side of the combustion chamber40. Fuel channels of the decomposition reaction section62are provided on the top of the preheat vaporization section63. In the example of this Figure, seven fuel channels are provided, each of which has an inverted triangle cross-section (two of them are half of the inverted triangle). Two lower sides of the inverted triangle contacts each of adjacent upper sides of the two triangles of the preheat vaporization section63. In other words, one fuel channel of the decomposition reaction section62is provided on the two fuel channels of the preheat vaporization section63so as to be sandwiched by its two fuel channels. The catalyst65is included in each fuel channel of the decomposition reaction section62. Such structure of the preheat vaporization section63and decomposition reaction section62is preferable, since an area of contact per unit volume between the preheat vaporization section63and the decomposition reaction section62can be increased. As a result, the heat exchange between the preheat vaporization section63and decomposition reaction section62can be more effective, and the pyrolysis reaction can be reliably progressed. Fuel channels of the outside cooling section61are provided on the top of the decomposition reaction section62. In the example of this Figure, four fuel channels each of which has a rectangular cross-section are provided. Then, one fuel channel of the outside cooling section61is provided on to 1.5 fuel channels of the decomposition reaction section62. However, the number of the fuel channels in each of above-mentioned sections is arbitrary.

In the example ofFIG. 6C, the preheat vaporization section63and the decomposition reaction section62are similar toFIG. 6B. The fuel channels of the outside cooling section61are provided on the top of the decomposition reaction section62. In the example of this Figure, seven fuel channels each of which has a triangle cross-section is provided (two of them are half of the triangle). The bottom line of the triangle contacts the upper side of the inverted triangle of the decomposition reaction section62. In other words, one fuel channel of the outside cooling section61is provided on one fuel channel of the decomposition reaction section62. Such structure of the outside cooling section61is preferable, since surface area per unit volume for contacting the outside can be increased in the outside cooling section61. Because of this, the heat-exchange between the outside cooling section61and the outside can be effective, and the temperature of the decomposition reaction section62can be easily controlled. The number of the fuel channels in each of the above-mentioned sections is arbitrary.

In the example ofFIG. 6D, the preheat vaporization section63is similar toFIG. 6B. The fuel channels of the decomposition reaction section62are provided on the top of the preheat vaporization section63. In the example of this Figure, five fuel channels each of which has a cross-section of diamond shape are provided. Two lower sides of the diamond shape contact adjacent upper sides of the two triangles of the preheat vaporization section63. In other words, one fuel channel of the decomposition section62is provided on the two fuel channels of the preheat vaporization section63so as to be sandwiched by two fuel channels. The catalyst65is included in the each fuel channel of the decomposition reaction section62. Such structure of the preheat vaporization section63and the decomposition reaction section62is preferable, since contact area per unit volume can be increased between the preheat vaporization section63and the decomposition reaction section62. Because of this, the heat-exchange between the preheat vaporization section63and the decomposition reaction section62can be effective, and the pyrolysis reaction can be reliably promoted. Fuel channels of the outside cooling section61are provided on the top of the decomposition reaction section62. In the example of this Figure, six fuel channels each of which has an inverted triangle cross-section are provided. Two lower sides of the inverted triangles contact adjacent upper sides of the two diamond shapes of the decomposition reaction section62. In other words, one fuel channel of the outside cooling section61is provided on the two fuel channels of the decomposition reaction section62so as to be sandwiched by two fuel channels. Such structure of the outside cooling section61is preferable, since contact surface area per unit can be increased between the outside cooling section61and the decomposition reaction section62. Because of this, the heat-exchange between the outside cooling section61and the decomposition reaction section62can be efficient, the heat-exchange between the outside cooling section61and the outside can be efficient, and the temperature of the decomposition reaction section62can be easily controlled. The number of the fuel channels in each of the above-mentioned sections is arbitrary.

According to these configurations, the effects explained byFIGS. 2A and 2Bcan be obtained. Also, for example, the cross-section of the fuel channels of the preheat vaporization section63may be a rectangular section, and each of fuel channels of the decomposition reaction section62and outside cooling section61may be a triangle and inverted triangle, or a triangle and diamond shape. Further, for example, fuel channels, each having a hexagonal cross-section shape, may be stacked to be a honeycomb, thereby providing the preheat vaporization section63(but, pentagon-shaped cross-section whose combustion chamber side is flat), the decomposition reaction section62, and the outside cooling section61. In these cases, the effects explained byFIGS. 2A and 2Bcan be also obtained.

As mentioned above, with reference to the embodiments, the fuel supply system, the scramjet engine and operation method of the same were explained, however, it is apparent that the present invention is not limited to the above-mentioned embodiment, and that each embodiment can be changed in a range of the technical ideas of the present invention. Furthermore, for example, the present invention can be applied not only to an aircraft but also to a flying object or a rocket.