Turbine interstage combustion chamber capable of strengthening mixing

Abstract

The invention discloses a turbine interstage combustion chamber capable of strengthening mixing, and relates to the technical field of aero-engine combustion, the turbine interstage combustion chamber comprises an outer shell and an inner shell which are concentrically arranged, a gap is formed between the outer shell and the inner shell, an axial main airflow channel is formed, and the side wall of the outer shell is provided with an axial main airflow channel extending towards the outer side of the outer shell; the airflow guider is arranged along the radius direction of the outer shell, is fixed between the outer shell and the inner shell, is positioned between the air inlet end of the outer shell and the annular airflow chamber and is hollow, and an air inlet hole is formed in one side, facing the air inlet end, of the airflow guider; the two side walls, away from the air inlet end, of the airflow guider are provided with gaps, so that airflow entering the airflow guider from the air inlet holes flows out of the gaps, radial guiding airflow perpendicular to the flowing direction of the axial main airflow channel is formed, the airflow flowing out of the gaps is perpendicular to the main airflow, and the mixing and exchanging speed of the airflow is increased.

Description

Technical Field

[0001] The invention relates to the technical field of aviation engine combustion, and more particularly to a turbine interstage combustion chamber with enhanced mixing. Background Art

[0002] In the field of modern aircraft engines, thrust-to-weight ratio is one of the key indicators for measuring performance. In order to improve the thrust-to-weight ratio, traditional methods include increasing the total compression ratio and the temperature before the turbine. However, due to the development of material technology, the temperature before the turbine has reached more than 1800K, which is difficult to achieve a significant increase in the short term. Therefore, afterburning technology has become an alternative solution to increase thrust, among which the turbine interstage combustor (ITB) has attracted attention as a new technology; the turbine interstage combustor is located between the high-pressure turbine and the low-pressure turbine, and its working principle is similar to that of the afterburner. The high-temperature gas coming out of the main combustion chamber has a lower temperature after passing through the high-pressure turbine, and the heat resistance strength of the low-pressure turbine still has margin, so oil is supplied between the turbines, and the high-temperature gas is used for secondary combustion between the turbines to provide more energy for the low-pressure turbine, thereby increasing the thrust of the engine. The interstage combustor, with its shorter axial distance, can achieve the purpose of reducing the weight of the engine, thereby improving the thrust-to-weight ratio of the engine.

[0003] However, the main problem faced by the interstage combustion chamber is that due to its short axial length and relatively limited overall space, the fuel residence time is an order of magnitude shorter than that of a conventional combustion chamber, making it difficult to organize combustion. At the same time, due to space limitations, the outlet temperature distribution of the interstage combustion chamber is uneven. Since the outlet of the interstage combustion chamber is the low-pressure turbine, the blades will be subjected to uneven heating intensity, reducing their service life.

[0004] Therefore, how to provide a turbine interstage combustion chamber that can stably burn under high-temperature and high-speed incoming flow conditions and achieve good outlet temperature distribution is a problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of this, the present invention provides a turbine interstage combustion chamber with enhanced mixing, aiming to solve the above-mentioned technical problems.

[0006] In order to achieve the above object, the present invention adopts the following technical solution:

[0007] A turbine interstage combustion chamber with enhanced mixing, comprising an outer casing and an inner casing arranged concentrically, wherein a gap is provided between the outer casing and the inner casing to form an axial main airflow channel, and an annular airflow chamber extending outwardly thereof and communicating with the axial main airflow channel is provided on the side wall of the outer casing, and further comprising an airflow guide:

[0008] The airflow guide is arranged along the radial direction of the outer shell and fixed between the outer shell and the inner shell. The airflow guide is located between the air inlet end of the outer shell and the annular airflow chamber and is hollow inside. An air inlet hole is opened on the side of the airflow guide facing the air inlet end. The two side walls of the airflow guide away from the air inlet end have gaps, so that the airflow entering the airflow guide from the air inlet hole flows out at the gap and forms a radial guided airflow perpendicular to the flow direction of the axial main airflow channel, so as to speed up the mixing and exchange speed between the axial mainstream channel and the annular airflow chamber.

[0009] Through the above technical scheme, the present invention discloses a turbine interstage combustion chamber with enhanced mixing, wherein high-temperature combustion gas flows into the axial main airflow channel, and most of the airflow bypasses the airflow guide and flows along the axial main airflow channel from both sides of the airflow guide. This part of the airflow generates suction when flowing through the annular airflow chamber, and part of the airflow is introduced into the interior of the annular airflow chamber to generate a vortex. A small part of the airflow enters the interior of the airflow guide through the air inlet, and then flows out radially from the gap on the side of the airflow guide close to the annular airflow chamber. The airflow flowing out of the gap is perpendicular to the main airflow, and the vertical flow helps to increase the contact area and interaction between the airflows, thereby accelerating the mixing and exchange speed between the airflows, and is beneficial to introducing the ignited oil-gas mixture in the annular airflow chamber into the axial mainstream channel, fully burning in the axial mainstream channel, avoiding the high-temperature zone from being concentrated near the outer shell close to the annular airflow chamber, improving the uniformity of the temperature distribution at the outlet of the interstage combustion chamber, and extending the life of the low-pressure turbine blades.

[0010] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the airflow guide includes a U-shaped plate and a baffle fixed between the outer shell and the inner shell, the open end of the U-shaped plate faces the annular airflow chamber, and the air inlet is opened on the middle plate of the U-shaped plate; there is a gap between the baffle and the open end of the U-shaped plate, and a radial guide airflow perpendicular to the axial main airflow channel is formed at the gap. Through the design of the U-shaped plate and the baffle, the path and method of airflow guidance are clarified, and the uniformity of airflow mixing and combustion is enhanced.

[0011] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the hollow setting of the airflow guide 5 can effectively reduce the overall weight while ensuring the strength, thereby improving the overall performance of the engine.

[0012] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the distance from the side wall of the annular airflow chamber close to the baffle to the air inlet end is greater than or equal to the distance from the baffle to the air inlet end, thereby optimizing the airflow guiding effect and making the radially guided airflow more uniform.

[0013] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the U-shaped plate and the baffle have the same height. The same height helps to maintain the stability and consistency of the airflow guide structure, so that the airflow flowing from the gap between the U-shaped plate and the baffle to both sides is consistent, further optimizing the airflow mixing effect.

[0014] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the cross section of the annular airflow chamber is a U-shaped structure, and an igniter is installed on its top wall, and the ignition end of the igniter passes through the top wall and extends to the inner side of the annular airflow chamber. The ignition operation in the combustion chamber can be conveniently realized, and the reliability and ignition efficiency of the combustion chamber are improved.

[0015] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, an oil supply pipe is installed inside the annular airflow chamber and on the side away from the air inlet end, and a plurality of oil injection holes are opened on the oil supply pipe. Installing the oil supply pipe inside the annular airflow chamber and spraying oil through a plurality of oil injection holes helps to fully mix the fuel and air, and improves the combustion efficiency and stability. Oil is only supplied inside the annular airflow chamber, and no oil supply device is set for the mainstream, which reduces the complexity of the structure and can also avoid ablation of the surface of the airflow guide.

[0016] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the injection direction of the oil injection hole is opposite to the airflow direction of the axial main airflow channel. The injection direction of the oil injection hole is opposite to the airflow direction of the axial main airflow channel, which can enhance the mixing effect of fuel and airflow and further improve combustion efficiency.

[0017] Preferably, in the above-mentioned turbine interstage combustion chamber with enhanced mixing, the angle between two adjacent fuel injection holes is 12-18°, which helps to achieve uniform distribution and full combustion of fuel and improve the performance and efficiency of the combustion chamber.

[0018] It can be seen from the above technical solutions that, compared with the prior art, the present invention discloses a turbine interstage combustion chamber with enhanced mixing, which has the following beneficial effects:

[0019] The present invention guides the airflow from the axial direction to the radial direction by arranging an annular airflow chamber and an airflow guide, thereby increasing the airflow mixing effect, making the fuel and air mix more evenly, and making the airflow more evenly distributed in the combustion chamber, reducing the phenomenon of local overheating or insufficient combustion, thereby enhancing the combustion stability and combustion efficiency; by opening a hole in the front of the U-shaped plate, a part of the airflow is allowed to pass through the inside of the airflow guide and be discharged from the gap between the U-shaped plate and the rear baffle, this airflow will enhance the mixing of the mainstream and the airflow in the annular airflow chamber, which is beneficial to introduce the ignited oil and gas mixture in the annular airflow chamber into the mainstream, fully burn it in the mainstream, avoid the high temperature zone from being concentrated near the outer shell near the annular airflow chamber, improve the uniformity of the temperature distribution at the outlet of the inter-stage combustion chamber, and extend the life of the low-pressure turbine blades. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying creative work.

[0021] Figure 1 The accompanying drawing is a schematic structural diagram of a turbine interstage combustion chamber with enhanced mixing provided by the present invention;

[0022] Figure 2 The accompanying drawing is a front view of a turbine interstage combustion chamber with enhanced mixing provided by the present invention;

[0023] Figure 3 The accompanying drawing is a top view of a turbine interstage combustion chamber with enhanced mixing provided by the present invention;

[0024] Figure 4 The attached picture is Figure 3 A cross-sectional view of Figure AA;

[0025] Figure 5 The accompanying drawing is a schematic diagram of the airflow direction of the turbine interstage combustion chamber with enhanced mixing provided by the present invention.

[0026] in:

[0027] 1- Outer shell;

[0028] 2-Inner shell;

[0029] 3- axial main air flow channel;

[0030] 4- annular airflow chamber;

[0031] 5- air flow guide;

[0032] 51-air inlet; 52-slit; 53-U-shaped plate; 54-baffle;

[0033] 6-Ignition device;

[0034] 7-Oil supply pipe. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] Participate in the Figure 1-5 The embodiment of the present invention discloses a turbine interstage combustion chamber with enhanced mixing, comprising an outer casing 1 and an inner casing 2 arranged concentrically, a gap being provided between the outer casing 1 and the inner casing 2, and an axial main airflow channel 3 being formed, and an annular airflow chamber 4 extending outward thereof and communicating with the axial main airflow channel is provided on the side wall of the outer casing 1, and also comprising an airflow guide 5:

[0037] The airflow guide 5 is arranged along the radial direction of the outer shell and fixed between the outer shell 1 and the inner shell 2. The airflow guide 5 is located between the air inlet end of the outer shell 1 and the annular airflow chamber 4, and its interior is hollow. An air inlet hole 51 is opened on the side of the airflow guide 5 facing the air inlet end, and the two side walls of the airflow guide 5 away from the air inlet end have gaps 52, so that the airflow entering the airflow guide 5 from the air inlet hole 51 flows out at the gap 52 and forms a radial guided airflow perpendicular to the flow direction of the axial main airflow channel 3.

[0038] In order to further optimize the above technical solution, the airflow guide 5 includes a U-shaped plate 53 and a baffle 54 fixed between the outer shell 1 and the inner shell 2, the open end of the U-shaped plate 53 faces the annular airflow chamber 4, and the air inlet 51 is opened on the middle plate of the U-shaped plate 53; there is a gap between the baffle 54 and the open end of the U-shaped plate 53, and a radial guiding airflow perpendicular to the axial main airflow channel 3 is formed at the gap.

[0039] In order to further optimize the above technical solution, the distance from the side wall of the annular airflow chamber 4 close to the baffle 54 to the air inlet end is equal to the distance from the baffle 54 to the air inlet end.

[0040] In order to further optimize the above technical solution, the heights of the U-shaped plate 53 and the baffle plate 54 are equal.

[0041] In order to further optimize the above technical solution, the width of the open end of the U-shaped plate 53 is the same as the width of the baffle 54 , so that the gaps on both sides between the baffle 54 and the open end of the U-shaped plate 53 are the same.

[0042] In order to further optimize the above technical solution, the cross-section of the annular airflow chamber 4 is a U-shaped structure, and an igniter 6 is installed on its top wall. The ignition end of the igniter 6 passes through the top wall and extends to the inside of the annular airflow chamber 4.

[0043] In order to further optimize the above technical solution, an oil supply pipe 7 is installed on the inner side of the annular airflow chamber 4 and away from the air inlet end, and a plurality of oil injection holes are opened on the oil supply pipe 7; the oil supply pipe 7 is distributed along the circumferential direction, and oil is supplied through a plurality of pipelines through the side of the annular airflow chamber 4 away from the baffle 54.

[0044] In order to further optimize the above technical solution, the oil injection direction of the oil injection hole is opposite to the air flow direction of the axial main air flow channel 3.

[0045] In order to further optimize the above technical solution, the angle between two adjacent injection holes is 12-18°.

[0046] The working principle of the present invention is:

[0047] The high-temperature combustion gas from the high-pressure turbine enters from the air inlet end. When it reaches the position of the airflow guide 5, most of the airflow bypasses the U-shaped plate 53 and flows through the two sides. A small part of the airflow enters the airflow guide 5 through the air inlet hole 51 of the U-shaped plate 53. This small part of the airflow flows out from the gaps 52 on both sides of the airflow guide 5, and the direction of the outflow is perpendicular to the direction of the mainstream. The annular airflow chamber 4 is the ignition zone, that is, the area where combustion occurs initially; when the mainstream airflow flows through the annular airflow chamber 4, it will produce entrainment, sucking a part of the airflow into the annular airflow chamber 4, generating a vortex. The direction of the vortex is as follows: Figure 4 As shown, this part of the airflow is mixed with the fuel coming out of the fuel injection hole, and then ignited by the igniter 6 to form a flame; at the same time, the vortex in the annular airflow chamber 4 also sends the ignited oil-gas mixture out of the annular airflow chamber 4 to merge with the mainstream. The mainstream gas will form a low-speed recirculation zone behind the baffle 54, so the high-temperature combustion gas in the annular airflow chamber 4 will flow downward along the baffle 54 and mix with more mainstream gas in the recirculation zone, so that the fuel is fully burned and the heat is completely released. Since gas will flow out of the gap 52 between the U-shaped plate 53 and the rear baffle 54, this part of the gas will push the mainstream to both sides, which is equivalent to increasing the width of the baffle 54, so that the area of ​​the recirculation zone is larger, thereby better stabilizing the flame. At the same time, the gas coming out of the gap 52 can change the airflow exchange structure between the mainstream and the annular airflow chamber 4, increase the airflow transfer from the annular airflow chamber 4 to the mainstream, and make the high-temperature combustion gas in the annular airflow chamber 4 transfer more to the mainstream, avoiding the high-temperature zone at the outlet of the interstage combustion chamber to be concentrated on the side close to the annular airflow chamber 4, making the outlet temperature distribution more uniform, preventing the low-pressure turbine blades behind the outlet of the interstage combustion chamber from being ablated, and extending the life of the entire engine.

[0048] In this specification, each embodiment is described in a progressive manner, and each embodiment focuses on the differences from other embodiments. The same or similar parts between the embodiments can be referred to each other. For the device disclosed in the embodiment, since it corresponds to the method disclosed in the embodiment, the description is relatively simple, and the relevant parts can be referred to the method part.

[0049] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A turbine interstage combustion chamber with enhanced mixing, comprising an outer casing (1) and an inner casing (2) arranged concentrically, wherein a gap is provided between the outer casing (1) and the inner casing (2) to form an axial main airflow channel (3), characterized in that: The outer shell (1) has a side wall with an annular airflow chamber (4) extending outward and communicating with the axial main airflow channel, and also includes an airflow guide (5): The airflow guide (5) is arranged along the radial direction of the outer shell and is fixed between the outer shell (1) and the inner shell (2). The airflow guide (5) is located between the air inlet end of the outer shell (1) and the annular airflow chamber (4), and is hollow inside. The airflow guide (5) is provided with an air inlet hole (51) on one side facing the air inlet end, and the two side walls of the airflow guide (5) away from the air inlet end have gaps (52), so that the airflow entering the airflow guide (5) from the air inlet hole (51) flows out at the gaps (52), and forms a radial guided airflow perpendicular to the flow direction of the axial main airflow channel (3).

2. A turbine interstage combustion chamber with enhanced mixing according to claim 1, characterized in that: The airflow guide (5) comprises a U-shaped plate (53) and a baffle (54) fixed between the outer shell (1) and the inner shell (2); the open end of the U-shaped plate (53) faces the annular airflow chamber (4); the air inlet hole (51) is provided on the middle plate of the U-shaped plate (53); a gap is provided between the baffle (54) and the open end of the U-shaped plate (53); a radial guiding airflow perpendicular to the axial main airflow channel (3) is formed at the gap.

3. A turbine interstage combustion chamber with enhanced mixing according to claim 2, characterized in that: The distance from the side wall of the annular airflow chamber (4) close to the baffle plate (54) to the air inlet end is equal to the distance from the baffle plate (54) to the air inlet end.

4. The turbine interstage combustion chamber with enhanced mixing according to claim 3, characterized in that: The U-shaped plate (53) and the baffle plate (54) have the same height.

5. The turbine interstage combustion chamber with enhanced mixing according to claim 1, characterized in that: The cross section of the annular airflow chamber (4) is a U-shaped structure, and an igniter (6) is installed on its top wall. The ignition end of the igniter (6) passes through the top wall and extends to the inside of the annular airflow chamber (4).

6. The turbine interstage combustion chamber with enhanced mixing according to claim 1, characterized in that: An oil supply pipe (7) is installed inside the annular airflow chamber (4) and on a side away from the air inlet end, and a plurality of oil injection holes are provided on the oil supply pipe (7).

7. A turbine interstage combustion chamber with enhanced mixing according to claim 6, characterized in that: The oil injection direction of the oil injection hole is opposite to the air flow direction of the axial main air flow channel (3).

8. The turbine interstage combustion chamber with enhanced mixing according to claim 7, characterized in that: The angle between two adjacent oil injection holes is 12-18°.

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