The tilted combustion chamber scheme of the integrated design of the coupled compressor and turbine

Abstract

The present invention discloses a tilted combustion chamber scheme with an integrated design of a coupled compressor and a turbine. The mainstream gas inside the annular flame tube of the combustion chamber adopts a flow form that rotates at a certain circumferential tangential angle, which not only increases the residence time of the gas, but also the high-speed gas at the flame tube outlet can directly drive the first-stage turbine blades to do work. The residual vortex airflow at the outlet of the last-stage rotor of the compressor and the combustion chamber head can be directly matched and designed, thereby omitting the compressor outlet guide and the turbine inlet guide structure. Since the present invention omits the compressor outlet guide and the turbine inlet guide respectively and shortens the axial length of the combustion chamber at the same time, the axial length of the engine can be greatly shortened, achieving the purpose of reducing the weight of the entire engine, thereby improving the thrust-to-weight ratio of the engine; at the same time, the turbine cooling air volume can be greatly reduced, reducing the difficulty of turbine design.

Description

Technical Field

[0001] The present invention belongs to the field of aviation engines and relates to a new integrated design scheme for the overall structure of an engine, including the design of three major components: a coupled compressor, a combustion chamber and a turbine. Background Art

[0002] At present, with the continuous development of aircraft engine technology, the requirements for the combustion performance of the engine combustion chamber are getting higher and higher. The combustion chamber of aircraft engines is developing towards a high thrust-to-weight ratio with high temperature rise and low weight, which requires that the weight of the engine itself should not be too heavy. In traditional engines, air is pressurized by a compressor, enters the combustion chamber and is mixed with fuel for combustion, and then the high-temperature and high-pressure gas heat energy is converted into mechanical work through the turbine. The turbine blades are connected to the compressor rotor through a mechanical transmission shaft, thereby driving the compressor to rotate. In order to improve the service life and energy transfer efficiency of the mechanical transmission shaft, the length of the mechanical transmission shaft must be as short as possible during high-speed design.

[0003] Due to the structure of the swirler at the head of the combustion chamber, the mainstream airflow in the combustion chamber of a traditional engine is required to flow along the axial direction of the engine to ensure its combustion efficiency; at the same time, the airflow entering the turbine blades is required to have a large tangential velocity to drive the turbine blades to work and ensure the efficient output of its shaft work. Therefore, it is necessary to set an outlet guide at the compressor outlet and an inlet guide at the turbine inlet to rectify the air and gas respectively, thereby forming an inlet / outlet airflow that can match the combustion chamber. This design leads to problems such as a longer overall length of the engine, a heavier weight of the engine itself, and large flow losses, especially the cooling problem of the turbine inlet guide is prominent. Summary of the invention

[0004] In view of the above problems, the present invention proposes an inclined combustion chamber with an integrated design of coupling compressor and turbine. The inclined combustion chamber changes the axial flow form of air into an inclined flow form with a certain tangential velocity in the annular combustion chamber by transforming the traditional axial flow head into an inclined swirl head with a certain angle. This design can omit structures such as the compressor outlet guide and the turbine inlet guide, thereby reducing the weight of the combustion chamber itself and shortening the length of the mechanical transmission shaft between the compressor and turbine. It can also greatly reduce the cooling requirements of the turbine inlet guide and improve the reliability of the engine.

[0005] The present invention is achieved in that:

[0006] An inclined combustion chamber with an integrated design of coupling a compressor and a turbine comprises an inclined combustion chamber casing, turbines arranged at both ends of the inclined combustion chamber casing, and a compressor; a mechanical transmission shaft is provided in the middle of the inclined combustion chamber casing, and the compressor and the turbine are connected via the mechanical transmission shaft; at the same time, the high-pressure rotating airflow at the outlet of the last-stage moving blade rotor of the compressor is directly introduced into the flame tube head of the inclined combustion chamber flame tube after passing through a diffuser.

[0007] The rear end of the inclined combustion chamber casing is directly connected to the turbine, and the interior of the combustion chamber casing is an annular inclined combustion chamber flame tube. Since the airflow inside the combustion chamber flame tube flows circumferentially, the length of the flame tube can be shortened, and the corresponding axial lengths of the mechanical transmission shaft and the combustion chamber casing are also shortened accordingly.

[0008] The head of the inclined combustion chamber flame tube is an angled inclined swirl head, so the air flow direction formed in the inclined combustion chamber flame tube after passing through the inclined swirl head is at an angle to the central axis of the combustion chamber. The present invention converts the axially flowing airflow in the traditional combustion chamber flame tube into an airflow with a tangential velocity. After the mainstream airflow flows obliquely, the axial length of the combustion chamber can be shortened, and the corresponding flame tube length and the length of the mechanical transmission shaft are also shortened accordingly. The present invention can increase the service life and mechanical energy transmission efficiency of the mechanical transmission shaft and reduce the processing difficulty of the structure.

[0009] Furthermore, the mainstream airflow inside the flame tube of the inclined combustion chamber flows along the annular combustion chamber in the inclined flow direction of the mainstream airflow in the flame tube of the inclined combustion chamber; the angle α between the inclined flow direction of the mainstream airflow in the flame tube of the inclined combustion chamber and the central axis of the combustion chamber is in the range of 10° to 45°. This solution can increase the residence time of the fuel in the flame tube, thereby improving the combustion efficiency; it can also greatly shorten the length of the flame tube while ensuring the complete combustion of the fuel. After the inlet air passes through the head of the combustion chamber, it forms an inclined flow air with a certain tangential velocity in the flame tube, and the inclined air and the fuel are mixed and burned to form an inclined high-temperature combustion gas.

[0010] Furthermore, the residual angular kinetic energy of the high-temperature combustion gas at the outlet of the inclined combustion chamber flame tube matches the first-stage turbine blades inside the turbine, directly driving the first-stage turbine blades to do work.

[0011] Furthermore, the air in the flame tube of the inclined combustion chamber flows in an inclined rotation, and its inclined momentum is provided by the last stage rotor of the compressor.

[0012] The working process of the inclined combustion chamber of the present invention is:

[0013] The mainstream airflow in the flame tube of the inclined combustion chamber flows obliquely downstream with a tangential velocity. The angle α between the oblique flow direction of the mainstream airflow in the flame tube of the inclined combustion chamber and the central axis of the combustion chamber is such that the air generates rotating air with a tangential velocity in the flame tube of the inclined combustion chamber. The actual macroscopic displacement is much larger than the axial length of the flame tube of the inclined combustion chamber, thereby ensuring complete combustion of the fuel and shortening the axial length of the flame tube.

[0014] After the rotating airflow with a certain tangential velocity flows out of the flame tube of the inclined combustion chamber, it directly impacts the first-stage turbine blades to perform external work. The residual swirl angle of the combustion gas with tangential velocity at the flame tube outlet matches the first-stage turbine blades, ensuring efficient conversion between the thermal energy and kinetic energy of the combustion gas and the mechanical energy of the turbine blades. Since the air in the flame tube of the inclined combustion chamber flows in an inclined and rotating manner, its tangential momentum can be provided by the last-stage rotor of the compressor. After the last-stage rotor of the compressor compresses the air and performs work, its pressure and velocity are further increased, and it has a strong circumferential tangential velocity. The air with tangential velocity enters the head of the flame tube of the inclined combustion chamber after passing through the diffuser.

[0015] The beneficial effects of the present invention and the prior art are:

[0016] 1) In the annular flame tube of the combustion chamber, a large range of high-temperature combustion gas is formed to rotate in the circumferential direction, which increases the residence time of the combustible mixture in the flame tube and improves the combustion efficiency. Therefore, while ensuring the same combustion efficiency, this design can greatly shorten the length of the flame tube, thereby shortening the length of the mechanical transmission shaft between the compressor and the flame tube and reducing the weight of the combustion chamber components.

[0017] 2) The high-temperature combustion gas at the flame tube outlet has a large tangential velocity and can directly impact the first-stage turbine blades to do work. Therefore, the inclined combustion chamber structure can abandon the turbine inlet guide structure in the traditional engine, thereby shortening the axial length of the turbine, reducing the weight of the engine itself, and improving the reliability of the turbine components. At the same time, it can greatly reduce the amount of gas used to cool the turbine inlet guide, reducing the difficulty of turbine design.

[0018] 3) The flame tube head of the inclined combustion chamber can be directly designed to match the rotating airflow with a certain tangential velocity at the outlet of the last-stage rotor of the compressor. There is no need to set a compressor outlet guide behind the last-stage rotor blades of the compressor, thereby shortening the axial length of the compressor, reducing the weight of the engine itself, and improving the reliability of the compressor components.

[0019] 4) Since the present invention omits the compressor outlet guide and the turbine inlet guide respectively and shortens the axial length of the combustion chamber, the axial length of the engine can be greatly shortened, thereby achieving the purpose of reducing the weight of the entire engine, thereby improving the thrust-to-weight ratio of the engine, and can greatly reduce the turbine cooling air volume and reduce the difficulty of turbine design. The design of the inclined combustion chamber shortens the axial length of the inclined combustion chamber, and the length of the high-speed rotating mechanical transmission shaft in the middle of the combustion chamber is also shortened accordingly. This design scheme can increase the service life and mechanical energy transmission efficiency of the mechanical transmission shaft and reduce the processing difficulty of the structure.

[0020] 5) The mainstream gas inside the annular flame tube of the combustion chamber of the present invention adopts a flow form that rotates at a certain circumferential tangential angle, which not only increases the residence time of the combustion gas, but also the high-speed combustion gas at the flame tube outlet can directly drive the first-stage turbine blades to do work, and can also directly match the residual vortex airflow at the outlet of the last-stage rotor of the compressor with the combustion chamber head, thereby omitting the compressor outlet guide and turbine inlet guide structures. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic diagram of a conventional aircraft engine in the specific embodiment of the present invention;

[0022] Figure 2 A schematic diagram of an integrated inclined combustion chamber coupled with a compressor outlet guide and a turbine inlet guide of the present invention;

[0023] Figure 3 is a flow vector diagram of the airflow inside the annular flame tube in an embodiment of the present invention;

[0024] Among them, 1-first stage turbine blades, 2-turbine inlet guide vane, 301-conventional combustion chamber casing, 302-inclined combustion chamber casing, 401-conventional combustion chamber flame tube, 402-inclined combustion chamber flame tube, 501-axial flow direction of mainstream airflow in the conventional combustion chamber flame tube, 502-inclined flow direction of mainstream airflow in the inclined combustion chamber flame tube, 601-mechanical transmission shaft of the conventional combustion chamber, 602-mechanical transmission shaft of the inclined combustion chamber, 7-diffuser, 8-compressor outlet guide vane, 9-last stage rotor of the compressor, 001-centerline of the combustion chamber. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solution and effect of the present invention clearer and more specific, the present invention is further described in detail by enumerating examples below. It should be noted that the specific implementation described here is only used to explain the present invention and is not used to limit the present invention.

[0026] like Figure 1As shown, in a conventional aircraft engine, a turbine inlet guide 2 is also provided between the combustion chamber casing 301 and the turbine, and the combustion chamber casing is a conventional combustion chamber flame tube 401. At the same time, after the high-pressure rotating airflow at the outlet of the last stage of the compressor rotor passes through the diffuser 7, a compressor outlet guide 8 needs to be provided. In a conventional aircraft engine, the turbine and the compressor are connected through a mechanical transmission shaft 601, and the turbine rotor drives the compressor rotor to rotate to compress the air. After the last stage of the compressor rotor 9 compresses the air and does work, the absolute kinetic energy increases while the pressure is increased, forming high-speed air with a certain tangential velocity; then, under the rectifying effect of the compressor outlet guide 8, the air gradually decelerates and expands along the guide blade channel, and the air with a certain tangential velocity is rectified into an axial airflow and enters the diffuser 7; and then passes through the flame swirler, main combustion hole, mixing hole and other structures at the head of the flame tube to enter the flame for fuel injection and combustion.

[0027] The mainstream gas in the combustion chamber flows along the axial flow direction 501 of the mainstream airflow in the traditional combustion chamber flame tube 401, and impacts the turbine inlet guide vane 2 after passing through the flame tube outlet. The high-temperature and high-pressure combustion gas converts pressure energy into power when flowing along the turbine inlet guide vane, forming combustion gas with a certain tangential velocity that impacts the turbine blades to perform external work. The turbine blades drive the connected compressor rotor to rotate through the mechanical transmission shaft 601.

[0028] The above is the working principle of the combustion chamber of a traditional axial-flow aircraft engine. This design makes the design of the compressor and turbine more difficult, the flow loss is larger, and the cooling air consumption of the turbine inlet guide is large. In the present invention, the axial flow form of the mainstream airflow in the traditional engine flame tube is reformed into an inclined flow form with a certain angle through a special flame tube head structure design. The specific schematic diagram is shown in FIG. Figure 2 shown.

[0029] First, the mainstream airflow in the annular inclined combustion chamber flame tube 402 of the present invention flows obliquely with a tangential velocity, such as Figure 2~3 As shown, L1 is set as the length of the turbine inlet guide vane, L 201 is the axial length of the flame tube in the traditional combustion chamber, L 202 is the axial length of the inclined combustion chamber flame tube, L3 is the length of the compressor outlet guide, and α is the angle between the mainstream airflow direction of the inclined combustion chamber and the central axis of the combustion chamber. The air generates a large range of rotating air with tangential velocity in the inclined combustion chamber flame tube 402, and its actual macroscopic displacement is much larger than the axial length of the flame tube. This design can shorten the axial length of the flame tube while ensuring that the fuel can be completely burned. Therefore, the axial length L of the inclined combustion chamber flame tube 202 Compared with the axial length L of the flame tube in the traditional combustion chamber 201 Compared with the previous example, L 202 <L201 , the length of the mechanical transmission shaft 602 connecting the compressor and the turbine is also shortened accordingly, which improves the transmission efficiency and service life of mechanical energy. 401 is a traditional flame tube, 402 is the flame tube involved in the present invention, and the axial length of the flame tube 402 of the inclined combustion chamber of the present invention is l 202 Less than l 201 .

[0030] Secondly, after the rotating airflow with a certain tangential velocity flows out of the flame tube, it can directly impact the first-stage turbine blades to perform external work. Through good aerodynamic design, it can be ensured that the residual swirl angle of the gas with tangential velocity at the flame tube outlet can match the first-stage turbine blades, ensuring efficient conversion between the thermal energy and kinetic energy of the gas and the mechanical energy of the turbine blades. Therefore, the design of the inclined combustion chamber can omit the turbine inlet guide structure, thereby reducing the cooling gas consumption of the turbine inlet guide and reducing the difficulty of turbine design; at the same time, it can shorten the axial length of the turbine, reduce the weight of the turbine, and improve the reliability of turbine components.

[0031] Finally, since the air in the annular flame tube is flowing in an oblique rotation, its tangential momentum can be provided by the last stage rotor 9 of the compressor. Because the pressure and speed of the last stage rotor 9 of the compressor are further improved after the air is compressed, and it has a strong circumferential tangential velocity, this design does not require the additional installation of a compressor outlet guide, omitting the compressor outlet guide 8 and abandoning the corresponding space length L3. This part of the air with tangential velocity can directly enter the flame tube head after passing through the diffuser 7. Therefore, this design does not need to provide straightening blades, so the compressor outlet guide can be omitted, shortening the compressor length, reducing weight, and improving the reliability of compressor components.

[0032] To sum up, the inclined combustion chamber can not only shorten the axial length of the flame tube, but also omit the compressor outlet guide vane 8 and the turbine inlet guide vane 2 structure, thereby shortening the axial lengths L1 and L3 corresponding to the compressor outlet guide vane 8 and the turbine inlet guide vane 2. This design scheme not only reduces the flow loss along the engine, but also shortens the axial length of the engine and reduces the weight of the engine itself, thereby achieving the purpose of increasing the thrust-to-weight ratio; at the same time, since the compressor outlet 8 and the turbine inlet guide vane 2 are reduced, the reliability of the aircraft engine is improved.

[0033] A high-temperature rotating airflow with a large range of circular circumferential motion will be formed in the inclined combustion chamber flame tube 402 of the present invention, thereby increasing the residence time of the oil-gas mixture in the flame tube and improving the combustion efficiency. Therefore, this structure can further reduce the length of the annular flame tube while ensuring the complete combustion time of the oil-gas mixture. The design of the inclined combustion chamber allows the high-temperature combustion gas at the annular flame tube outlet to have a large circumferential tangential velocity, which is roughly the same as the direction of the airflow velocity at the outlet of the traditional turbine inlet guide vane. Therefore, the airflow at the outlet of the inclined combustion chamber flame tube can directly impact the first-stage turbine moving blades to perform external work. Therefore, the turbine inlet guide vane structure is abandoned, the cooling air volume of the turbine inlet guide vane is reduced, and the difficulty of turbine design is reduced.

[0034] The design of the inclined combustion chamber of the present invention allows the flame tube head air intake structure to be directly matched with the residual swirling air with a certain tangential velocity at the outlet of the last stage rotor of the compressor, and the air with tangential momentum passing through the compressor outlet guide is introduced into the flame tube through the flame tube head swirler, which helps to form high-temperature combustion gas with a certain tangential velocity. Therefore, the compressor outlet guide structure can be discarded.

[0035] The above description is only a preferred embodiment of the present invention. It should be pointed out that a person skilled in the art can make several improvements without departing from the principle of the present invention, and these improvements should also be regarded as within the protection scope of the present invention.

Claims

1. An inclined combustion chamber with an integrated design of a coupled compressor and a turbine, characterized in that: The invention comprises an inclined combustion chamber casing (302), a turbine and a compressor arranged at both ends of the inclined combustion chamber casing (302); a mechanical transmission shaft (602) is arranged in the middle of the inclined combustion chamber casing (302), and the compressor and the turbine are connected via the mechanical transmission shaft (602); and a high-pressure rotating airflow at the outlet of the last-stage rotor (9) of the compressor is directly introduced into the flame tube head of the inclined combustion chamber flame tube (402) after passing through a diffuser (7); The rear end of the inclined combustion chamber casing (302) is directly connected to the turbine, and the interior of the combustion chamber casing is an annular inclined combustion chamber flame tube (402), the airflow inside the inclined combustion chamber flame tube (402) is a circumferential flow, and the head of the inclined combustion chamber flame tube (402) is an angled inclined swirl head, so the air flow direction formed in the inclined combustion chamber flame tube (402) after passing through the inclined swirl head presents an angle with the central axis of the combustion chamber; the mainstream airflow inside the inclined combustion chamber flame tube (402) flows along the annular combustion chamber in the inclined flow direction (502) of the mainstream airflow in the inclined combustion chamber flame tube; The working process of the inclined combustion chamber is: The mainstream airflow in the inclined combustion chamber flame tube (402) flows obliquely downstream with a tangential velocity. The angle α between the oblique flow direction (502) of the mainstream airflow in the inclined combustion chamber flame tube and the central axis (001) of the combustion chamber is such that the air generates rotating air with a tangential velocity in the inclined combustion chamber flame tube (402). The actual macroscopic displacement of the rotating air is much larger than the axial length of the inclined combustion chamber flame tube (402), thereby ensuring complete combustion of the fuel and shortening the axial length of the flame tube. After the rotating airflow with a certain tangential velocity flows out of the inclined combustion chamber flame tube (402), it directly impacts the first-stage turbine blades to perform external work. The residual swirl angle of the combustion gas with the tangential velocity at the flame tube outlet matches the first-stage turbine blades, ensuring efficient conversion between the thermal energy and kinetic energy of the combustion gas and the mechanical energy of the turbine blades. Since the air in the inclined combustion chamber flame tube (402) flows in an inclined rotating manner, its tangential momentum is just provided by the last-stage rotor (9) of the compressor. After the last-stage rotor (9) of the compressor compresses the air and performs work, its pressure and velocity are further increased, and it has a strong circumferential tangential velocity. The air with the tangential velocity passes through the diffuser (7) and enters the head of the inclined combustion chamber flame tube (402).

2. The inclined combustion chamber of the integrated design of the coupled compressor and turbine according to claim 1 is characterized in that: The angle α between the inclined flow direction (502) of the mainstream airflow in the flame tube of the inclined combustion chamber and the central axis (001) of the combustion chamber is in the range of 10° to 45°.

3. The inclined combustion chamber of the integrated design of the coupled compressor and turbine according to claim 1 is characterized in that: The residual angular kinetic energy of the high-temperature combustion gas at the outlet of the inclined combustion chamber flame tube (402) matches the first-stage turbine blades (1) inside the turbine, directly driving the first-stage turbine blades (1) to perform work.

4. The inclined combustion chamber of the integrated design of the coupled compressor and turbine according to claim 1 is characterized in that: The air in the inclined combustion chamber flame tube (402) flows in an inclined rotation, and its inclined momentum is provided by the last stage rotor (9) of the compressor.

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