A microturbine jet engine with afterburner

Abstract

The present application relates to a kind of small turbojet with afterburner, including core engine, tail nozzle, also including afterburner, the afterburner two ends are connected core engine and tail nozzle respectively;Gas flow direction sequentially through core engine, afterburner, tail nozzle.The tail nozzle of the present application is subsonic convergent tail nozzle, can carry out tail nozzle area size adjustment, to make engine efficiency and afterburning efficiency maximum, compared with the performance of traditional small turbojet is more excellent, simultaneously make afterburning control more simple and reliable, broaden the use scene of small aeroengine.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engines, in particular to a micro turbojet engine with afterburner. BACKGROUND

[0002] The micro turbojet engine is a kind of aero-engine with low manufacturing cost, short service life, light weight and small thrust, which is generally applied in the fields of model aircraft, fixed-wing unmanned aerial vehicle, glider, target drone and cruise missile.

[0003] For the micro turbojet engine, due to the use of manufacturing, maintenance cost and design application scene, the current micro turbojet engine has almost zero application of afterburning technology. For the micro turbojet engine, the additional mass of the accessory device, afterburner and the supporting nozzle required for afterburning is too large, which leads to the decrease of fuel economy and significantly reduces the thrust-to-weight ratio of the whole engine. From the perspective of specific technical implementation, the micro turbojet engine has a narrow afterburning interval. Since the total pressure of the gas after the turbine of the micro turbojet engine is low, forced afterburning may cause the total pressure in the afterburner to be higher than the total pressure after the turbine, leading to backflow and surge of the turbine, causing the engine to stop. If the combustion is excessive, supersonic airflow may be generated in the afterburner, generating a series of shock waves, affecting the state adjustment of the nozzle, and if the nozzle configuration adopts a supersonic nozzle to adapt to the shock wave, the core engine efficiency when not using afterburning will be significantly reduced. If a subsonic nozzle is used, it cannot cooperate with the afterburning to generate shock waves, causing the afterburner to overheat, the gas flow to be poor, and the afterburning efficiency to be greatly reduced.

[0004] If the micro turbojet engine is combined with afterburning technology, the following technologies need to be solved: determination of the nozzle configuration, optimization of the diffuser, simplification of the engine accessories, selection of the afterburning ignition technology path, common working control of the afterburner and the core engine, and additional and appropriate air combustion.

[0005] With the development of technology and the demand of society for the performance of aero-engine, higher requirements are put forward for the performance of micro-aero-engine, especially in the military field, new equipment such as cruise missile has higher standards for the performance and reliability of micro-turbojet engine, in some cases, fuel economy is not considered, and the maximum thrust in a short time is pursued, so as to cope with some special situations, such as terminal military attack, balance of multiple engine thrust, rapid take-off of aircraft, etc., and for aero-engine, the afterburning can realize the short-time large increase of engine thrust, realize the demand, but only increasing the afterburning chamber cannot meet the demand, and the matched subsonic nozzle, afterburning chamber air supply device, common control of optimized afterburning fuel system and core engine fuel system, optimization of afterburning chamber structure for micro-turbojet engine are also needed, thus, it is necessary to design a turbojet engine with afterburning chamber, and the present application is committed to combining micro-turbojet engine with afterburning, and hopes to provide reference for future related research. SUMMARY

[0006] The purpose of the present application is to provide a micro-turbojet engine with afterburning chamber, which combines afterburning technology with micro-turbojet engine, realizes the great improvement of the performance of micro-turbojet engine, and considers the use reliability and convenient control at the same time, solving the problem of insufficient instantaneous performance of the existing micro-turbojet engine in the background art.

[0007] The present application is realized by the following technical scheme.

[0008] A micro-turbojet engine with afterburning chamber, comprising a core engine, a nozzle, and an afterburning chamber, wherein the two ends of the afterburning chamber are connected with the core engine and the nozzle respectively, and the gas flow passes through the core engine, the afterburning chamber and the nozzle in sequence.

[0009] The core engine comprises a compressor impeller, a core engine casing, a core engine combustion chamber, a turbine, a turbine guide vane, a main shaft, a supporting bearing, a spark plug, a core engine fuel pipe and a compressor diffuser disc, wherein the compressor impeller, the core engine combustion chamber and the turbine are located in the core engine casing, the compressor impeller and the turbine are jointly installed on the main shaft through the supporting bearing by interference fit, the compressor impeller is installed at the front end of the core engine casing through the compressor diffuser disc, the turbine is installed at the rear end of the core engine casing through the turbine guide vane, the core engine combustion chamber is between the compressor impeller and the turbine, the spark plug is installed on the core engine casing, the ignition end of the spark plug is installed outside the core engine combustion chamber, and the core engine fuel pipe connects the main fuel tank and the core engine combustion chamber.

[0010] The afterburner comprises an afterburner casing, a diffusion type flame standing flow combustion stabilizing groove, an afterburning fuel pipe, a fuel atomizer, an air bleed hole, an air bleed check valve, and an afterburning matching surface.

[0011] The tail nozzle is a subsonic convergent tail nozzle, which is composed of multiple guide plates, and the convergence degree of the tail nozzle 3 is controlled by controlling the rotation angle of the guide plates along the axis.

[0012] Further, the core engine belongs to a centrifugal gas generator.

[0013] Further, the support bearings at the compressor impeller connect the main shaft and the compressor diffuser disc, and the support bearings at the turbine connect the main shaft and the turbine guide vane, and a 0-2-0 type layout is adopted.

[0014] Further, the diffusion type standing flow flame stabilizing groove is composed of an outer standing flow combustion stabilizing groove and an inner standing flow combustion stabilizing groove, and the diffusion opening angles of the inner and outer standing flow combustion stabilizing grooves are the same.

[0015] Further, the afterburner casing is composed of multiple segments, and each segment is connected by an outer casing bolt.

[0016] Further, the core engine, the afterburner, and the tail nozzle are connected by an outer bolt.

[0017] Further, the afterburning fuel pipe and the core engine fuel pipe are connected by an outer fuel pipe, the fuel sources are the same main fuel tank, the same type of fuel is used, and a fuel pump and an oil-gas separator are shared; an electromagnetic throttle valve is arranged at the connection between the core engine fuel pipe and the afterburner fuel pipe, the electromagnetic throttle valve is opened when the core engine is in the maximum state and afterburning is performed, the minimum regulating flow of the electromagnetic throttle valve is the critical ignition fuel supply amount of the afterburner, and the maximum regulating flow is the critical temperature fuel supply amount of the afterburner.

[0018] Furthermore, the maximum expansion inner wall diameter of the tail nozzle is the same as the diameter of the mating surface of the afterburner. When the electromagnetic throttle valve is in the minimum throttling state, the afterburner is in the critical ignition state, and the tail nozzle is in the minimum convergence state. When the electromagnetic throttle valve is in the maximum throttling state, the afterburner is in the critical temperature state, and the tail nozzle is in the maximum expansion state. If the afterburner is not activated, the tail nozzle can also adjust its convergence according to the state of the core engine.

[0019] Furthermore, the afterburner is ignited by the combustion gas after the turbine. Since the afterburner is not equipped with an ignition device, when afterburning is required, the core engine is always at its maximum capacity, and the temperature of the combustion gas after the turbine is sufficient to ignite the afterburning fuel.

[0020] Compared with the prior art, the advantages of the present invention are:

[0021] 1. By organically combining afterburning technology with micro turbojet engines, the small size and low mass of micro turbojet engines are ensured, while the instantaneous thrust of the engines is greatly increased. This further improves the performance indicators of aircraft, such as flight speed, maneuverability, and flight envelope, enabling aircraft to be used in more scenarios.

[0022] 2. By designing a novel diffusion-type flame stabilization combustion trough in the afterburner, it is better suited to the core engine based on a centrifugal compressor. This type of compressor has a low internal air velocity and a high pressure ratio. The core engine based on the centrifugal compressor has a low combustion temperature in the core engine combustion chamber, a high main shaft speed, a low turbine inlet temperature, and subsonic airflow throughout the entire process. Considering these characteristics, the diffusion-type flame stabilization combustion trough has a weaker deceleration effect on the airflow and less pressure loss compared to the traditional V-type flame stabilization combustion trough suitable for axial-flow turbojet engines. This results in higher afterburner efficiency and thus greater effective thrust for the engine.

[0023] 3. By using a subsonic convergent nozzle, the gas expansion during afterburning can be balanced, maintaining the gas in a critical operating state as much as possible. This allows the gas to reach sonic speeds at the nozzle exit section, increasing thrust while maintaining a sufficient turbine pressure ratio. This ensures the total pressure recovery coefficient within the core engine combustion chamber, improving afterburning efficiency and effectively guaranteeing core engine stability, thus balancing the operation of the core engine and afterburning. Furthermore, the subsonic convergent nozzle can adjust the turbine pressure ratio of the core engine without afterburning, improving core engine efficiency. It can also regulate the gas flow rate during core engine start-up acceleration, preventing overheating during startup.

[0024] 4. By merging the fuel lines of the core engine and the afterburner, and supplementing them with electromagnetic throttle valve control, fuel control is simplified, while the weight of engine accessories is reduced, fuel economy and overall thrust-to-weight ratio are improved, and the failure rate of the fuel system is reduced.

[0025] 5. By igniting the afterburner with the exhaust gas from the turbine, the engine avoids overheating and burning out if the afterburner is forcibly ignited before the core engine reaches its maximum capacity or before the core engine starts, thus improving engine safety. Attached Figure Description

[0026] Figure 1 This is a schematic cross-sectional view of the overall structure of the present invention;

[0027] Figure 2 This is a schematic diagram of the overall structure and components of the present invention;

[0028] Figure 3 This is a cross-sectional view of the core structure of the present invention;

[0029] Figure 4 This is a cross-sectional view of the afterburner structure of the present invention;

[0030] Figure 5 This is a structural diagram of the tail nozzle of the present invention;

[0031] Figure 6 This is a schematic diagram of the core machine structure after the casing has been removed in this invention;

[0032] Figure 7 This is a structural diagram of the air inlet surface of the diffusion-type flame stabilization combustion groove of the present invention;

[0033] Figure 8 This is a structural diagram of the exhaust surface of the diffusion-type flame stabilization combustion trough of the present invention;

[0034] Figure 9 This is a partial schematic diagram of the fuel line section in the afterburner.

[0035] In the diagram: 1. Core engine; 2. Afterburner; 3. Tail nozzle; 101. Compressor impeller; 102. Core engine casing; 103. Core engine combustion chamber; 104. Turbine; 105. Turbine guide vane; 106. Main shaft; 107. Support bearing; 108. Spark plug; 109. Core engine fuel line; 110. Compressor diffuser; 201. Afterburner casing; 202. Diffusion-type flame stabilization combustion trough; 212. External stabilization combustion trough; 222. Internal stabilization combustion trough; 203. Afterburner fuel line; 204. Fuel atomizer; 205. Bleed air port; 206. Bleed air check valve; 207. Afterburner mating surface; 301. Straightener. Detailed Implementation

[0036] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship commonly used when the product is in use. They are used only for the convenience of describing the invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the invention. In the description of this invention, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set," "install," and "connect" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0037] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings, but these are not intended to limit the scope of the invention.

[0038] like Figures 1 to 3 As shown, a miniature turbojet engine with an afterburner includes a core engine 1, an exhaust nozzle 3, and an afterburner 2, the two ends of which are connected to the core engine 1 and the exhaust nozzle 3 respectively; the gas flow direction passes through the core engine 1, the afterburner 2, and the exhaust nozzle 3 in sequence.

[0039] The core engine 1 includes a compressor impeller 101, a core engine casing 102, a core engine combustion chamber 103, a turbine 104, a turbine guide vane 105, a main shaft 106, a support bearing 107, a spark plug 108, a core engine fuel line 109, and a compressor diffuser 110. The compressor impeller 101, the core engine combustion chamber 103, and the turbine 104 are located within the core engine casing 102. The compressor impeller 101 and the turbine 104 are jointly mounted on the main shaft 106 via the support bearing 107, using an interference fit. The compressor impeller 101 is connected to the compressor diffuser 110. The pressure plate 110 is installed at the front end of the core engine casing 102, the turbine 104 is installed at the rear end of the core engine casing 102 via the turbine guide 105, the core engine combustion chamber 103 is located between the compressor impeller 101 and the turbine 104, the spark plug 108 is installed on the core engine casing 102, and the ignition end of the spark plug 108 is installed on the outside of the core engine combustion chamber 103, the core engine fuel pipe 109 connects the main fuel tank and the core engine combustion chamber 103; when ignited, the flame front spreads in a ring along the combustion gas, and finally each evaporator port in the core engine combustion chamber 103 is covered by flame.

[0040] like Figure 4As shown, the afterburner 2 includes an afterburner casing 201, a diffusion-type flame-stabilized combustion stabilization groove 202, an afterburner fuel pipe 203, a fuel atomizer 204, an air bleed port 205, an air bleed one-way valve 206, and an afterburner mating surface 207. The diffusion-type flame-stabilized combustion stabilization groove 202 is installed at the front end of the afterburner 2, and an air bleed port 205 is opened at the front end of the afterburner 2. The air bleed port 205 corresponds to the position of the diffusion-type flame-stabilized combustion stabilization groove 202, and the air bleed one-way valve 206 is installed inside the air bleed port 205. An external air pump is used to introduce air to aid combustion, while preventing excessive pressure inside the afterburner 2 from causing gas leakage. It is important to note that fuel should be introduced first to ignite the gas and ensure a fuel-rich combustion before starting the air pump to introduce air for combustion. Otherwise, introducing air first will lower the temperature of the afterburner 2, making it difficult for the gas after the turbine to ignite the afterburning fuel, resulting in ignition failure. When the afterburner is not activated, the bleed air pump should be turned off to ensure the total temperature and pressure of the gas after the turbine, allowing it to continue to expand and accelerate in the afterburner 2.

[0041] like Figure 9 , Figure 4 As shown, an afterburning fuel pipe 203 is installed on the afterburner housing 201. Fuel is injected into the afterburner 2 through annularly distributed fuel atomizers 204. The combustion zone is located after the diffusion-shaped stabilizing flame combustion groove 202 and before the tail nozzle 3. The afterburning fuel pipe 203 does not directly contact the cylindrical surface of the afterburner housing 201, but is fixed by a bracket on the afterburner housing 201. This can minimize the risk of fuel leakage due to uneven heating of the afterburning fuel pipe 203, which could lead to deformation and rupture of the fuel line and thus cause a flight accident. The afterburning mating surface 207 is located inside the afterburner housing 201, and there is a gap between the afterburning mating surface 207 and the afterburner housing 201.

[0042] like Figure 5 As shown, the tail nozzle 3 is a subsonic convergent tail nozzle, which is composed of multiple guide vanes 301. The convergence of the tail nozzle 3 is controlled by controlling the rotation angle of the guide vanes 301 along the axis.

[0043] Furthermore, the core engine 1 is a centrifugal gas generator. The combustion temperature of the core engine combustion chamber 103 is relatively low, the main shaft 106 rotates at a relatively high speed, the temperature before the turbine is relatively low, and the airflow flows at subsonic speed throughout the entire process. It should be noted that all the relevant designs of this invention are based on the premise of a centrifugal gas generator.

[0044] Furthermore, the support bearing 107 at the compressor impeller 101 connects the main shaft 104 to the compressor diffuser 110, and the support bearing 107 at the turbine 104 connects the main shaft 106 to the turbine guide 105, adopting a 0-2-0 type layout.

[0045] Furthermore, such as Figure 4 , Figure 7 , Figure 8 As shown, the diffusion-type stabilizing flame groove 202 is composed of an outer stabilizing combustion groove 212 and an inner stabilizing combustion groove 222. The diffusion angle of the inner stabilizing combustion groove 222 is the same as that of the outer stabilizing combustion groove 212. The inner stabilizing combustion groove 222 and the outer stabilizing combustion groove 212 are used to match the afterburner mating surface 207. This configuration allows some of the combustion gas to pass through the gap between the afterburner mating surface 207 and the afterburner casing 201 to form a gas film, which effectively cools the afterburner casing 201 and ensures that the afterburner casing 201 does not undergo thermal stress deformation, which would cause poor centering of the afterburner casing 201 and further affect the injection direction of the tail nozzle 3, resulting in an imbalance between the thrust direction line and the engine center of gravity.

[0046] Furthermore, such as Figure 2 , Figure 4 As shown, the afterburner casing 201 is composed of multiple casing sections, each of which is externally connected by bolts on the outside of the casing.

[0047] Furthermore, the core engine 1, afterburner 2, and tail nozzle 3 are externally connected by external bolts.

[0048] Furthermore, such as Figure 2 As shown, the afterburner fuel pipe 203 and the core engine fuel pipe 109 are connected by an external fuel line. The fuel source is the same as the main fuel tank, and the same type of fuel is used. They share a fuel pump and a fuel-air separator. An electromagnetic throttle valve is installed at the connection between the core engine fuel pipe 109 and the afterburner fuel pipe 203. The electromagnetic throttle valve opens when the core engine 1 is in its maximum state and afterburner combustion is in progress. The minimum adjustable flow rate of the electromagnetic throttle valve is the critical ignition fuel supply of the afterburner, and the maximum adjustable flow rate is the critical temperature fuel supply of the afterburner.

[0049] Furthermore, such as Figure 5 As shown, the maximum expansion inner wall diameter of the tail nozzle 3 is the same as the diameter of the afterburner mating surface 207. When the electromagnetic throttle valve is in the minimum throttling state, the afterburner is in the critical ignition state, and the tail nozzle 3 is in the minimum convergence state. When the electromagnetic throttle valve is in the maximum throttling state, the afterburner is in the critical temperature state, and the tail nozzle 3 is in the maximum expansion state. If the afterburner is not activated, the tail nozzle 3 can also adjust its convergence according to the core engine state.

[0050] Furthermore, such as Figure 2 , Figure 4As shown, the afterburner 2 is ignited by the combustion gas after the turbine 104. The afterburner 2 is not equipped with an ignition device; when afterburning is required, the core engine 1 is always at its maximum capacity, and the temperature of the combustion gas after the turbine is sufficient to ignite the afterburning fuel. This method of igniting the afterburner fuel with the combustion gas after the turbine avoids forcibly igniting the afterburner 2 when the core engine 1 is not at its maximum capacity or is not running, which could cause engine overheating and burnout, thus improving engine safety.

[0051] The above description is merely a preferred embodiment of the present invention and does not limit the implementation and protection scope of the present invention. Those skilled in the art should realize that any equivalent substitutions and obvious changes made based on the description and illustrations of the present invention should be included within the protection scope of the present invention.

Claims

1. A miniature turbojet engine with an afterburner, comprising a core engine (1) and a tailpipe (3), characterized in that, It also includes an afterburner (2), the two ends of which are connected to the core engine (1) and the tail nozzle (3); The core machine (1) includes a compressor impeller (101), a core machine casing (102), a core machine combustion chamber (103), a turbine (104), a turbine guide vane (105), a main shaft (106), a support bearing (107), a spark plug (108), a core machine fuel line (109), and a compressor diffuser (110). The compressor impeller (101), the core machine combustion chamber (103), and the turbine (104) are located inside the core machine casing (102). The compressor impeller (101) and the turbine (104) are mounted together on the main shaft via the support bearing (107). On (106), the compressor impeller (101) is installed at the front end of the core engine casing (102) through the compressor diffuser (110), and the turbine (104) is installed at the rear end of the core engine casing (102) through the turbine guide (105). The core engine combustion chamber (103) is located between the compressor impeller (101) and the turbine (104). The spark plug (108) is installed on the core engine casing (102), and the ignition end of the spark plug (108) is installed outside the core engine combustion chamber (103). The core engine fuel pipe (109) connects the main fuel tank and the core engine combustion chamber (103). The afterburner (2) includes an afterburner casing (201), a diffusion-type flame-stabilized combustion stabilization groove (202), an afterburner fuel pipe (203), a fuel atomizer (204), an air vent (205), an air vent check valve (206), and an afterburner mating surface (207). The diffusion-type flame-stabilized combustion stabilization groove (202) is installed at the front end of the afterburner (2), and an air vent (205) is opened at the front end of the afterburner (2). The air vent (205) corresponds to the position of the diffusion-type flame-stabilized combustion stabilization groove (202). (205) is equipped with an air bleed one-way valve (206) and introduces air to assist combustion through an external air pump. The afterburner casing (201) is equipped with an afterburner fuel pipe (203). Fuel is injected into the afterburner (2) through an annularly distributed fuel atomizer (204). The combustion zone is located after the diffusion-shaped stabilizing flame combustion groove (202) and before the tail nozzle (3). The afterburner mating surface (207) is located inside the afterburner casing (201). There is a gap between the afterburner mating surface (207) and the afterburner casing (201). The tail nozzle (3) is a subsonic convergent tail nozzle, which is composed of multiple guide plates (301). The convergence of the tail nozzle (3) is controlled by controlling the rotation angle of the guide plates (301) along the axis.

2. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The core unit (1) is a centrifugal gas generator.

3. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The support bearing (107) at the compressor impeller (101) connects the main shaft (106) and the compressor diffuser (110), and the support bearing (107) at the turbine (104) connects the main shaft (106) and the turbine guide (105).

4. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The diffusion-type stabilizing flame groove (202) is composed of an outer stabilizing combustion groove (212) and an inner stabilizing combustion groove (222), and the diffusion angle of the inner stabilizing combustion groove (222) is the same as that of the outer stabilizing combustion groove (212).

5. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The afterburner casing (201) is composed of multiple casing sections, each of which is externally connected by bolts on the outside of the casing.

6. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The core engine (1), afterburner (2), and tail nozzle (3) are externally connected by external bolts.

7. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The afterburning fuel pipe (203) and the core engine fuel pipe (109) are connected by an external fuel line. The fuel source is the same as the main fuel tank, the same type of fuel is used, and a fuel pump and oil-gas separator are shared. An electromagnetic throttle valve is provided at the connection between the core engine fuel pipe (109) and the afterburning fuel pipe (203). The electromagnetic throttle valve opens when the core engine (1) is in its maximum state and afterburning is in progress. The minimum adjustable flow rate of the electromagnetic throttle valve is the critical ignition fuel supply of the afterburning combustion chamber, and the maximum adjustable flow rate is the critical temperature fuel supply of the afterburning combustion chamber.

8. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The maximum expansion inner wall diameter of the tail nozzle (3) is the same as the pipe diameter of the mating surface (207) of the afterburner. When the electromagnetic throttle valve is in the minimum throttle state, the afterburner is in the critical ignition state, and the tail nozzle (3) is in the minimum convergence state. When the electromagnetic throttle valve is in the maximum throttle state, the afterburner is in the critical temperature state, and the tail nozzle (3) is in the maximum expansion state. If the afterburner is not activated, the tail nozzle (3) can also adjust its convergence according to the core engine state.

9. A miniature turbojet engine with an afterburner according to claim 1, characterized in that, The afterburner (2) is ignited by the gas after the turbine (104).

Images