CN112814807B - Phase-change ramjet engine containing paraffin fuel - Google Patents
Phase-change ramjet engine containing paraffin fuel Download PDFInfo
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- CN112814807B CN112814807B CN202011549315.3A CN202011549315A CN112814807B CN 112814807 B CN112814807 B CN 112814807B CN 202011549315 A CN202011549315 A CN 202011549315A CN 112814807 B CN112814807 B CN 112814807B
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K7/00—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof
- F02K7/10—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines
- F02K7/105—Plants in which the working fluid is used in a jet only, i.e. the plants not having a turbine or other engine driving a compressor or a ducted fan; Control thereof characterised by having ram-action compression, i.e. aero-thermo-dynamic-ducts or ram-jet engines using a solid fuel
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- C—CHEMISTRY; METALLURGY
- C06—EXPLOSIVES; MATCHES
- C06B—EXPLOSIVES OR THERMIC COMPOSITIONS; MANUFACTURE THEREOF; USE OF SINGLE SUBSTANCES AS EXPLOSIVES
- C06B33/00—Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide
- C06B33/06—Compositions containing particulate metal, alloy, boron, silicon, selenium or tellurium with at least one oxygen supplying material which is either a metal oxide or a salt, organic or inorganic, capable of yielding a metal oxide the material being an inorganic oxygen-halogen salt
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
- F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
- F02C3/26—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C3/00—Gas-turbine plants characterised by the use of combustion products as the working fluid
- F02C3/20—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products
- F02C3/26—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension
- F02C3/28—Gas-turbine plants characterised by the use of combustion products as the working fluid using a special fuel, oxidant, or dilution fluid to generate the combustion products the fuel or oxidant being solid or pulverulent, e.g. in slurry or suspension using a separate gas producer for gasifying the fuel before combustion
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/04—Air intakes for gas-turbine plants or jet-propulsion plants
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/08—Heating air supply before combustion, e.g. by exhaust gases
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02C—GAS-TURBINE PLANTS; AIR INTAKES FOR JET-PROPULSION PLANTS; CONTROLLING FUEL SUPPLY IN AIR-BREATHING JET-PROPULSION PLANTS
- F02C7/00—Features, components parts, details or accessories, not provided for in, or of interest apart form groups F02C1/00 - F02C6/00; Air intakes for jet-propulsion plants
- F02C7/22—Fuel supply systems
- F02C7/224—Heating fuel before feeding to the burner
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
- F02K1/78—Other construction of jet pipes
- F02K1/80—Couplings or connections
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02K—JET-PROPULSION PLANTS
- F02K1/00—Plants characterised by the form or arrangement of the jet pipe or nozzle; Jet pipes or nozzles peculiar thereto
- F02K1/78—Other construction of jet pipes
- F02K1/80—Couplings or connections
- F02K1/805—Sealing devices therefor, e.g. for movable parts of jet pipes or nozzle flaps
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
- F23R—GENERATING COMBUSTION PRODUCTS OF HIGH PRESSURE OR HIGH VELOCITY, e.g. GAS-TURBINE COMBUSTION CHAMBERS
- F23R3/00—Continuous combustion chambers using liquid or gaseous fuel
- F23R3/42—Continuous combustion chambers using liquid or gaseous fuel characterised by the arrangement or form of the flame tubes or combustion chambers
- F23R3/58—Cyclone or vortex type combustion chambers
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Inorganic Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Combustion Methods Of Internal-Combustion Engines (AREA)
Abstract
The invention discloses a phase-change paraffin-containing fuel ramjet engine which adopts the integrated design of a combustion chamber and a gasification chamber, and has compact structure and high energy utilization rate. The casing is heated by a large amount of heat released by combustion reaction in the combustion chamber, the surface of the paraffin-containing fuel can be preheated under the action of radiation and convection heat transfer, and meanwhile, ram air is also heated, so that the surface of the fuel has higher temperature, and the phase change of the fuel is facilitated. The mode conversion is simple to realize, and the automatic switching between the boosting section and the punching section can be completed by utilizing the change of the pressure. The head of the combustion chamber is provided with a tapered hole with a certain inclination, so that the gas can swirl, and higher combustion efficiency can be obtained. When the boosting section and the punching section are switched, the mixture of the phase change product and air generates rotational flow under the action of the tapered hole when flowing into the combustion chamber, and the mixing effect is good. The size of the engine can be adjusted, the application range is wide, and the engine is suitable for a power system of a supersonic aircraft.
Description
Technical Field
The invention relates to the design and manufacturing technology of a ramjet, in particular to a phase-change type paraffin-containing fuel ramjet with good fuel mechanical property and high combustion efficiency; the power system is suitable for the supersonic aircraft.
Background
The rocket ramjet is an air-breathing engine with fuel and using oxygen in air for combustion, and can be divided into three types, namely a solid rocket ramjet, a liquid fuel ramjet and a solid fuel ramjet according to different fuel forms. The solid rocket ramjet has the characteristics of easy combustion organization and simple structure, but the adopted fuel-rich propellant contains part of oxidant, so the specific impulse is relatively low, and the liquid fuel ramjet and the solid fuel ramjet only carry fuel, so the energy level is high. For a liquid fuel ramjet engine, kerosene is generally adopted as a fuel, so that the liquid fuel ramjet engine has the advantages of high specific impulse and easy adjustment of fuel flow, and is widely applied to medium and long-range tactical missiles, but the engine needs to be provided with a high-pressure fuel supply system, and the fuel flow adjustment system is complex, so that the engine is high in cost and complex in working process; meanwhile, the density of the kerosene is low, so that the specific impact of the engine is not high.
In comparison, the solid fuel ramjet engine does not need a fuel supply and flow regulation system, and has the advantages of simple structure, high reliability and lower cost. The engine generally adopts hydrocarbon high molecular polymers such as hydroxyl-terminated polybutadiene (HTPB) and the like as solid fuel, however, due to the low temperature of supersonic ram air, the heat flow transmitted to the surface of the solid fuel may not be enough to cause the solid fuel to generate rapid thermal decomposition, so that the fuel gas generation rate is low, and the engine is difficult to stably work. In addition, because the residence time of the high-speed airflow in the combustion chamber is short, the pyrolysis products of the solid fuel cannot be fully mixed and combusted with air, and the combustion efficiency of the engine is also low. Therefore, the development of solid fuel with high gas generation rate and the effective combustion structure have important significance for the development and application of the solid fuel ramjet.
The paraffin is used as a solid fuel with high combustion surface retreating speed, and has a good application prospect in a solid fuel ramjet engine. The improvement of the Paraffin Fuel has been studied, and a laboratory-scale Paraffin Fuel Ramjet engine composed of an igniter, an air inlet, an air preheating chamber, a flame nozzle, a combustion chamber and a nozzle is proposed in the published document "Experimental investment of High Regression Rate Paraffin for Solid Fuel Ramjet processing" (AIAA processing and Energy 2019Forum conference, 8.19.2019-8.22.2019); the combustion chamber includes preceding combustion chamber, paraffin grain, back combustion chamber, and some firearm are placed at the center of inlet end apron, radially encircle and set up four intake ducts, and high-speed air flows in from the intake duct, and some firearm ignition simultaneously, and air and combustion products mix in the air preheating chamber, flow into the combustion chamber through flame nozzle, burn with the paraffin grain, and the gas is discharged with higher speed from the spray tube inflation.
The paraffin fuel ramjet disclosed by the literature has the following defects that the solid fuel adopting pure paraffin as the main component has poor mechanical property and can generate the fracture problem when the ramjet works; the heterogeneous combustion reaction between the paraffin fuel and the air is limited by diffusion reaction, and the residence time of the high-speed incoming flow air is short, so that the combustion efficiency of the engine is low. In order to solve the problem of low combustion efficiency, the sizes of the air preheating chamber and the post combustion chamber can be lengthened so as to uniformly mix fuel and air, but the size of the whole engine is lengthened, and certain limitation is generated on practical application.
Disclosure of Invention
In order to avoid the defects in the prior art, the invention provides a phase-change type paraffin-containing fuel ramjet engine; the ramjet adopts the integrated design of the combustion chamber and the gasification chamber, has compact structure and high energy utilization rate; the casing is heated by a large amount of heat released by combustion reaction in the combustion chamber, and under the action of radiation and heat convection, the surface of the paraffin-containing fuel can be preheated, and meanwhile, ram air is also heated, so that the surface of the fuel has higher temperature, and the fuel is favorable for phase change of the fuel.
The invention solves the technical problem by adopting the technical scheme that the device comprises an ignition wire, a rear end cover, an outer compression surface, bolts, end cover outer ring bolts, a gasification chamber cylindrical section flange, a phenolic resin plate, a graphite sealing ring, a combustion chamber cylindrical section flange, a paraffin-containing fuel grain, a solid propellant grain, a conical graphite block, an igniter and an engine, and is characterized in that the engine comprises a spray pipe, an air inlet channel, a gasification chamber and a combustion chamber, wherein the air inlet channel is distributed in the circumferential direction of the gasification chamber in a cross manner, and the inlet of the air inlet channel is provided with the outer compression surface for decelerating and pressurizing air flow facing at high speed;
the rear end cover is arranged on the spray pipe, the outer diameter of the rear end cover is the same as that of the gasification chamber, the central inner hole of the rear end cover is in a round table shape and is used for being matched with the convergence section of the spray pipe, and two circles of through holes with the same number are radially arranged on the rear end cover and are used for being connected with the flange of the cylinder section of the gasification chamber and the flange of the cylinder section of the combustion chamber;
the gasification chamber comprises a cylinder section and a circular head cover plate, a tubular paraffin-containing fuel grain is arranged in the cylinder section, 4 square groove type air inlets are formed in the tail of a shell of the cylinder section and used for communicating an air inlet channel with the gasification chamber, air flows into the gasification chamber through the air inlets, and radians are formed in the front and the back of the hole grooves, so that abrupt separation of a flow boundary layer at a step can be reduced; the head of the gasification chamber is bonded with an igniter, and an ignition wire is led out from the spray pipe;
the combustion chamber comprises a cylindrical section and an annular head cover plate, the head cover plate is circumferentially provided with a screw hole, the head cover plate is connected with the gasification chamber through a bolt, and one side of the lower part of the screw hole, which is close to the gasification chamber, is provided with a groove for mounting a graphite sealing ring; the inner side of the head cover plate is chamfered to ensure that the gas flows stably, and the space in the center of the circular ring is used for placing an igniter arranged on the gasification chamber; a tubular solid propellant grain is arranged in the cylindrical section, a plurality of conical holes with inclination in the radial direction are formed in the cylindrical part between the grain and the head cover plate, and conical graphite blocks are plugged in the conical holes; the tail part of the cylinder section is provided with a flange of the cylinder section of the combustion chamber, the flange is connected with the rear end cover through an end cover bolt and an end cover outer ring bolt, and the lower part of the screw hole is provided with a groove close to one side of the combustion chamber and used for installing a graphite sealing ring;
the gasification chamber is connected with the combustion chamber through a bolt at the head part, the gasification chamber and the spray pipe are connected with a cylindrical section flange of the gasification chamber through a rear end cover at the tail part, and the combustion chamber and the spray pipe are connected with the rear end cover through a cylindrical section flange of the combustion chamber through threads, so that the integration of the whole structure of the engine is realized; the phenolic resin plate is arranged at the rear part of the gasification chamber and is used for filling empty grooves at flanges of the cylinder section of the gasification chamber and the cylinder section of the combustion chamber, so that the gas can stably flow, and the flow loss is reduced.
Graphite sealing rings are arranged between the rear end cover and the flange of the cylindrical section of the gasification chamber, between the rear end cover and the flange of the cylindrical section of the combustion chamber, and between the rear end cover and the head of the gasification chamber and between the head of the combustion chamber, and are used for preventing high-temperature and high-pressure gas from leaking.
The solid propellant grain adopts a three-component propellant, the oxidant is ammonium perchlorate, the adhesive is hydroxyl-terminated polybutadiene, and the metal fuel is aluminum powder.
The cylinder section of the gasification chamber is internally provided with a paraffin-containing fuel grain, paraffin is taken as a main body, an energy-containing adhesive is taken as a matrix, and the selected energy-containing adhesive comprises polyaziridine glycidyl ether, 3-azidomethyl-3-methyloxybutane, 3-diazidomethyloxybutane, 3-diazidomethyloxybutane and tetrahydrofuran copolymer.
Advantageous effects
The invention provides a phase-change type paraffin-containing fuel ramjet engine; the integrated design of the combustion chamber and the gasification chamber is adopted, the structure is compact, and the energy utilization rate is high; the casing is heated by a large amount of heat released by combustion reaction in the combustion chamber, the surface of the paraffin-containing fuel can be preheated under the action of radiation and convection heat transfer, and meanwhile, ram air is also heated, so that the surface of the fuel has higher temperature, and the phase change of the fuel is facilitated.
The invention adopts high-energy phase-change paraffin-containing fuel, and has the characteristic of high gas generation rate; the fuel components are easy to change phase in a high-temperature environment, and exist in liquid and gas forms after the phase change, so that the combustion organization is easier, a large amount of fuel gas can be generated, the combustion efficiency is high, and the generated thrust can meet the requirements of an engine.
The phase-change paraffin-containing fuel adopted by the invention has the advantages of high energy property and low price requirement; the fuel takes paraffin as filler and energetic adhesive as matrix, has high theoretical specific impulse, and has the advantages of good mechanical property and high density. The paraffin is used as a petroleum byproduct, the source is wide, the price is low, and the paraffin content in the fuel containing the paraffin can reach 80 percent, so the total cost of the fuel is low.
The phase-change paraffin-containing fuel adopted by the invention has the advantages of easy phase-change reaction and high phase-change conversion rate; because the melting boiling points of the paraffin are low, the paraffin is easy to melt and evaporate, and entrained liquid drops can be generated under the sweeping action of high-speed airflow; meanwhile, the energetic binder is easy to generate thermal decomposition reaction, the surface of the fuel can be heated by the released heat, and the entrainment of liquid drops of paraffin can also be promoted, so the phase change process of the fuel is easy to occur.
The phase-change paraffin-containing fuel ramjet engine has simple realization of modal conversion, and can complete the automatic switching of the boosting section and the punching section by utilizing the change of pressure. The conical graphite block matched with the pore diameter is plugged in the conical hole at the head of the combustion chamber in advance, when the solid propellant burns, the pressure intensity of the combustion chamber is higher than that of the gasification chamber, and at the moment, the combustion chamber and the gasification chamber can be isolated by the conical graphite block, so that the loss of fuel gas in the boosting section is prevented; after the solid propellant is combusted, the pressure of the gasification chamber is higher than that of the combustion chamber due to the certain pressure of ram air, the conical graphite block is automatically separated, and the mixture of the phase change product and air flows into the combustion chamber to be continuously combusted, namely the switching from the boosting section to the stamping section is completed. The invention designs the taper hole at the head of the combustion chamber with a certain inclination, can realize the rotational flow of gas, and further can obtain higher combustion efficiency. When the boosting section and the punching section are switched, the mixture of the phase change product and air generates rotational flow under the action of the tapered hole when flowing into the combustion chamber, and the mixing effect is good. The size of the engine can be adjusted according to actual conditions, the application range is wide, the engine can be integrally matched with various aircraft projectiles, and the engine can be applied to a power system of a range-extended aircraft; the power system is suitable for the supersonic aircraft.
Drawings
The phase-change type paraffin-containing fuel ramjet engine of the present invention will be described in further detail with reference to the accompanying drawings and embodiments.
FIG. 1 is a schematic view of a phase change paraffinic containing fuel ramjet engine of the present invention.
Fig. 2 is a left side view of the phase change type paraffin-containing fuel ramjet engine of the present invention.
Fig. 3 is a right side view of a phase change paraffin-containing fuel ramjet engine of the present invention.
Fig. 4 is a cross-sectional view of a phase change type paraffin-containing fuel ramjet engine according to the present invention.
Fig. 5 isbase:Sub>A sectional view taken along linebase:Sub>A-base:Sub>A of fig. 4.
Fig. 6 is an enlarged view at I of fig. 4.
Fig. 7 is an enlarged view at ii of fig. 4.
Fig. 8 is a schematic gas flow diagram of a phase change paraffinic fuel containing ramjet engine with a tubular charge of solid propellant in the combustion chamber.
FIG. 9 is a schematic diagram of the swirling of the gas in the direction B-B of FIG. 8.
Fig. 10 is a schematic gas flow diagram of a phase change paraffin-containing fuel ramjet engine with a solid propellant in the combustion chamber using a conical charge.
In the figure
1. Ignition wire 2, spray pipe 3, rear end cover 4, air inlet channel 5, outer compression surface 6, gasification chamber 7, bolt 8 and end cover bolt
9. End cover outer ring bolt 10, gasification chamber cylinder section flange 11, phenolic resin plate 12, graphite sealing ring
13. Combustion chamber cylinder section flange 14, paraffin-containing fuel grain 15, solid propellant grain 16 and combustion chamber
17. Conical graphite block 18 igniter
Detailed Description
This embodiment is a phase change, paraffin-containing fuel ramjet engine.
Referring to fig. 1 to 10, the phase-change type paraffin-containing fuel ramjet engine of the present embodiment is composed of an ignition wire 1, a rear end cover 3, an outer compression surface 5, a bolt 7, an end cover bolt 8, an end cover outer ring bolt 9, a gasification chamber cylindrical section flange 10, a phenolic resin plate 11, a graphite seal ring 12, a combustion chamber cylindrical section flange 13, a paraffin-containing fuel grain 14, a solid propellant grain 15, a conical graphite block 17, an igniter 18, and an engine; the engine comprises a spray pipe 2, an air inlet channel 4, a gasification chamber 6 and a combustion chamber 16, wherein a rear end cover 3 is installed on the spray pipe 2, the outer diameter of the rear end cover 3 is the same as that of the gasification chamber, a central inner hole is in a circular truncated cone shape and is used for being matched with a convergence section of the spray pipe 2, and two circles of 8 through holes are distributed in a cover plate and are used for being connected with a cylinder section flange 10 of the gasification chamber and a cylinder section flange 13 of the combustion chamber.
The air inlet channel 4 is composed of a shell and an outer compression surface 5 at an inlet, the air inlet is in a chamfer rectangle shape, the outer compression surface 5 is a two-dimensional slope surface, and therefore the supersonic incoming flow is decelerated and pressurized through a series of oblique shock waves before entering the inlet section of the air inlet channel. 4 air inlet channels 4 are distributed around the gasification chamber 6 in a cross-shaped layout, and a certain space is reserved between the front part and the middle part of each air inlet channel 4 and the shell of the gasification chamber 6 and can be used for assembling the projectile body part of the aircraft; the back part is welded on the shell of the gasification chamber 6, and the position of the back part is matched with the 4 square groove holes on the shell of the gasification chamber 6.
The gasification chamber 6 comprises a cylinder section and a circular head cover plate, a tubular paraffin-containing fuel grain 14 is arranged in the cylinder section, the fuel takes paraffin as a main body, an energy-containing adhesive as a matrix, the available energy-containing adhesive mainly comprises polyazidyl glycidyl ether, 3-azido methyl-3-methyloxybutane, 3-diazido methyloxybutane and tetrahydrofuran copolymer high molecular polymers, and aluminum powder, a curing agent, a burning rate catalyst and other components can be added according to actual needs. The tail part of the shell of the cylinder section is provided with 4 square groove type air inlets for communicating the air inlet channel 4 with the gasification chamber 6, air flows into the gasification chamber 6 through 4 holes, and the front part and the rear part of the hole groove have certain radians, so that abrupt change type separation of a flow boundary layer at the step of the shell can be reduced as much as possible. A gasification chamber cylinder section flange 10 is arranged behind the air inlet hole, 8 inner screw holes are formed in the flange and connected with the rear end cover 3 through an end cover outer ring bolt 9, and a circle of groove is formed in one side, close to the shell of the gasification chamber 6, above the screw holes and used for installing a graphite sealing ring 12 to achieve sealing. An annular phenolic resin plate 11 is bonded below the gasification chamber cylindrical section flange 10 and is used for filling empty grooves at the positions of the gasification chamber cylindrical section flange 10 and the combustion chamber cylindrical section flange 13, so that gas flow loss can be reduced, and the passive quality of an engine can be reduced due to the fact that the density of phenolic resin is low. The cover plate at the head part of the gasification chamber 6 is provided with 8 through holes for connecting with the combustion chamber 16, the inner wall of the cover plate is bonded with an igniter 18, and an ignition wire 1 is connected with the igniter and led out of the engine from the spray pipe 2.
The combustion chamber 16 comprises a cylinder section and a circular head cover plate, the cover plate is provided with 8 inner screw holes and is connected with the gasification chamber 6 through bolts 7, and one side of the lower part of each screw hole, which is close to the gasification chamber 6, is provided with a circle of groove for installing a graphite sealing ring 12. The inner side of the cover plate is chamfered to stabilize the gas flow, and the space in the center of the ring is used for placing an igniter 18 installed on the gasification chamber 6. The cylinder section is internally provided with a solid propellant grain 15 with a specific shape, three-component propellant can be adopted, the oxidant is ammonium perchlorate, the adhesive is hydroxyl-terminated polybutadiene, the metal fuel is aluminum powder, and the shape of the propellant grain is tubular. Six tapered holes with inclination in the radial direction are arranged at the cylindrical part between the medicine column and the head cover plate, and tapered graphite blocks 17 are plugged in the tapered holes. The tail part of the cylinder section is provided with a combustion chamber cylinder section flange 13, the flange plate is provided with 8 inner screw holes and is connected with the rear end cover 3 through an end cover bolt 8, and one side of the lower part of the screw hole, which is close to the combustion chamber 16, is provided with a circle of groove for installing a graphite sealing ring 12 and preventing high-temperature and high-pressure gas leakage.
Engine assembly process
The paraffin-containing fuel grain 14 is loaded into the gasification chamber 6 in a free loading mode, the igniter 18 is connected with the ignition wire 1, and the ignition wire is adhered to the center of the cover plate at the head part of the shell of the gasification chamber 6 by epoxy resin glue. The combustion chamber 16, which is filled with the conical graphite block 17, is then connected to the gasification chamber 6 by means of screws, and the solid propellant grains 15 are introduced into the combustion chamber 16 in a freely filling manner. The flange 10 of the cylinder section of the gasification chamber is welded on the shell of the gasification chamber 6, the flange 13 of the cylinder section of the combustion chamber is welded on the shell of the combustion chamber 16, and the annular phenolic resin plate 11 is adhered under the flange 10 of the cylinder section of the gasification chamber and used for filling the gap between the flange and the flange 13 of the cylinder section of the combustion chamber. And then the spray pipe 2 welded with the rear end cover 3 is respectively connected with a combustion chamber cylindrical section flange 13 and a gasification chamber cylindrical section flange 10 through an end cover bolt 8 and an end cover outer ring bolt 9, so that an integrated structure of the spray pipe 2, the gasification chamber 6 and the combustion chamber 16 is realized. And finally, welding the 4 air inlet channels 4 around the shell of the gasification chamber 6 to complete the assembly of the engine.
Working process of engine
Firstly, after an igniter is electrified, the solid propellant is ignited by gas generated by deflagration, the propellant is combusted in a combustion chamber, and the generated gas is expanded and accelerated by a spray pipe, so that heat energy is converted into kinetic energy to accelerate an engine. When the air is accelerated to a certain speed, the oncoming high-speed air flows into the air inlet channel, and enters the gasification chamber after being decelerated and pressurized. At the moment, the solid propellant heats the shell of the combustion chamber in the combustion process, so that the solid propellant has higher temperature, the surface of the paraffin-containing fuel is preheated under the action of convection heat transfer, and meanwhile, the temperature of stamping air is higher, which creates favorable conditions for the phase change of the fuel. When the paraffin-containing fuel undergoes phase change, a binder in the fuel undergoes a thermal decomposition reaction, the decomposition products exist in the form of a gas phase, paraffin is melted and evaporated, the paraffin exists in the gas phase in the form of paraffin droplets and paraffin vapor, and the phase change products flow with a high-speed gas flow in the gasification chamber at a high speed. Because the gasification chamber and the combustion chamber have larger pressure difference, the graphite block on the tapered hole is automatically separated, the mixture of the phase change product and the air flows into the combustion chamber for combustion reaction, and the fuel gas expands and accelerates through the jet pipe to generate thrust. Along with the combustion, the wall surface of the combustion chamber is always in a high-temperature state, and the surface of the paraffin-containing fuel is continuously heated through radiation and convection heat transfer, so that the phase change process is stably carried out.
Example 1
Taking 80% of paraffin, 10% of poly-azido glycidyl ether, 5% of aluminum powder, 3% of toluene diisocyanate and 2% of magnesium powder as raw materials according to the mass percent, preparing a tubular paraffin-containing fuel grain, and filling the grain into a gasification chamber in a free filling manner; taking 70% of ammonium perchlorate, 10% of hydroxyl-terminated polybutadiene, 15% of aluminum powder, 3% of toluene diisocyanate and 2% of magnesium powder as raw materials by mass percent, preparing a tubular solid propellant grain, and filling the tubular solid propellant grain into a combustion chamber in a free filling mode.
After the engine and a certain product missile body are assembled, the igniter is electrified, the solid propellant is ignited by the gas generated by deflagration, the solid propellant is combusted in the combustion chamber, and the generated gas is expanded and accelerated by the spray pipe to convert heat energy into kinetic energy so as to accelerate the missile. When the air is accelerated to a certain speed, the oncoming high-speed air flows into the air inlet channel, and enters the gasification chamber after being decelerated and pressurized. At the moment, the solid propellant heats the shell of the combustion chamber in the combustion process to enable the shell to have higher temperature, the surface of the paraffin-containing fuel is preheated under the action of convection heat transfer, meanwhile, the temperature of the ram air is higher, the paraffin is melted and evaporated and exists in a gas phase in the form of paraffin droplets and paraffin steam, the energy-containing adhesive polynitrogen glycidyl ether is subjected to thermal decomposition reaction, the decomposition product exists in the form of a gas phase, and the phase change product flows in the gasification chamber at high speed along with high-speed airflow. As the gasification chamber and the combustion chamber have larger pressure difference, the graphite block on the tapered hole is automatically separated, the mixture of the phase change product and the air flows into the combustion chamber and carries out combustion reaction, and the gas expands and accelerates through the spray pipe to generate thrust to push the missile to advance. Along with the combustion, the wall surface of the combustion chamber is always in a high-temperature state, and the surface of the paraffin-containing fuel is continuously heated through radiation and convection heat transfer, so that the phase change process can be stably carried out.
Example 2
Taking 75% of paraffin, 15% of 3, 3-diazide methyl oxybutane, 5% of aluminum powder, 3% of isophorone diisocyanate and 2% of magnesium powder in percentage by mass as raw materials to prepare the paraffin-containing fuel. A tubular medicine shape is adopted and is filled into a gasification chamber in a free filling mode; taking 65% of ammonium perchlorate, 10% of hydroxyl-terminated polybutadiene, 20% of aluminum powder, 3% of isophorone diisocyanate and 2% of magnesium powder as raw materials by mass percent to prepare the solid propellant. The conical charge type is adopted and is loaded into a combustion chamber in a free filling mode.
After the engine and a certain product missile body are assembled, the igniter is electrified, the solid propellant is ignited by the gas generated by deflagration, the solid propellant is combusted in the combustion chamber, and the generated gas is expanded and accelerated by the spray pipe to convert heat energy into kinetic energy so as to accelerate the missile. When the air is accelerated to a certain speed, the oncoming high-speed air flows into the air inlet channel, and enters the gasification chamber after being decelerated and pressurized. At the moment, the solid propellant heats the shell of the combustion chamber in the combustion process to enable the shell to have higher temperature, the surface of the paraffin-containing fuel is preheated under the action of convection heat transfer, meanwhile, the temperature of the ram air is higher, the paraffin is melted and evaporated and exists in a gas phase in the form of paraffin droplets and paraffin steam, the energy-containing adhesive 3, 3-diazido-methyloxybutane is subjected to thermal decomposition reaction, the decomposition product exists in the form of the gas phase, and the phase change product flows at high speed in the gasification chamber along with high-speed airflow. As the gasification chamber and the combustion chamber have larger pressure difference, the graphite block on the tapered hole is automatically separated, the mixture of the phase change product and the air flows into the combustion chamber and carries out combustion reaction, and the gas expands and accelerates through the spray pipe to generate thrust to push the missile to advance. Along with the combustion, the wall surface of the combustion chamber is always in a high-temperature state, and the surface of the paraffin-containing fuel is continuously heated through radiation and convection heat transfer, so that the phase change process can be stably carried out.
Claims (4)
1. The phase-change paraffin-containing fuel ramjet engine is characterized by also comprising a jet pipe, an air inlet channel, a gasification chamber and a combustion chamber, wherein the air inlet channel is arranged in the circumferential direction of the gasification chamber in a cross manner, and the inlet of the air inlet channel is provided with an outer compression surface for decelerating and pressurizing high-speed head-on air flow; the rear end cover is arranged on the spray pipe, the outer diameter of the rear end cover is the same as that of the gasification chamber, the central inner hole of the rear end cover is in a round table shape and is used for being matched with the convergence section of the spray pipe, and two circles of through holes with the same number are radially arranged on the rear end cover and are used for being connected with the flange of the cylinder section of the gasification chamber and the flange of the cylinder section of the combustion chamber;
the gasification chamber comprises a cylinder section and a circular head cover plate, a tubular paraffin-containing fuel grain is arranged in the cylinder section, 4 square groove type air inlets are formed in the tail of a shell of the cylinder section and are used for communicating an air inlet channel with the gasification chamber, air flows into the gasification chamber through the air inlets, radians are formed in the front and the back of each square groove type air inlet, and abrupt separation of a flow boundary layer at a step can be reduced; the head of the gasification chamber is bonded with an igniter, and an ignition wire is led out from the spray pipe;
the combustion chamber comprises a cylindrical section and an annular head cover plate, the head cover plate is circumferentially provided with a screw hole, the head cover plate is connected with the gasification chamber through a bolt, and one side of the lower part of the screw hole, which is close to the gasification chamber, is provided with a groove for mounting a graphite sealing ring; the inner side of the head cover plate is chamfered to ensure that the gas flows stably, and the space in the center of the circular ring is used for placing an igniter arranged on the gasification chamber; a tubular solid propellant grain is arranged in the cylindrical section, a plurality of conical holes with inclination in the radial direction are formed in the cylindrical part between the grain and the head cover plate, and conical graphite blocks are plugged in the conical holes; a combustion chamber cylinder section flange is arranged at the tail part of the cylinder section, the flange is connected with the rear end cover through an end cover bolt, and a groove is formed in one side, close to the combustion chamber, of the lower part of the screw hole and used for installing a graphite sealing ring;
the gasification chamber is connected with the combustion chamber through a bolt at the head part, the gasification chamber is connected with the spray pipe through a rear end cover at the tail part and a flange of a cylindrical section of the gasification chamber, and the combustion chamber is connected with the spray pipe through a flange of the cylindrical section of the combustion chamber and a rear end cover, so that the integration of the whole structure of the engine is realized; the phenolic resin plate is arranged at the rear part of the gasification chamber and is used for filling empty grooves at flanges of the cylinder section of the gasification chamber and the cylinder section of the combustion chamber, so that the gas can stably flow, and the flow loss is reduced.
2. The phase-change paraffin-containing fuel ramjet engine as claimed in claim 1, wherein graphite seal rings are disposed between the rear end cover and the flange of the cylinder section of the gasification chamber, between the rear end cover and the flange of the cylinder section of the combustion chamber, and between the head of the gasification chamber and the head of the combustion chamber, for preventing leakage of high-temperature and high-pressure gas.
3. The phase-change paraffin-containing fuel ramjet engine as claimed in claim 1, wherein the solid propellant grains are made of a three-component propellant, the oxidizer is ammonium perchlorate, the binder is hydroxyl-terminated polybutadiene, and the metal fuel is aluminum powder.
4. The phase-change paraffin-containing fuel ramjet engine according to claim 1, wherein the cylindrical section of the gasification chamber is filled with a paraffin-containing fuel charge which comprises paraffin as a main body and an energy-containing adhesive as a matrix, wherein the selected energy-containing adhesive comprises polyazidyl glycidyl ether, 3-azidomethyl-3-methyloxybutane, 3-diazidomethyloxybutane, 3-diazidomethyloxybutane and tetrahydrofuran copolymer.
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