A turbo interstage combustion chamber with enhanced mixing

Abstract

The application discloses a reinforced mixed turbine interstage combustion chamber and relates to the technical field of aero-engine combustion, which comprises a concentrically arranged outer shell and an inner shell, a gap is formed between the outer shell and the inner shell, and an axial main airflow channel is formed; a side wall of the outer shell is provided with an annular airflow chamber extending to the outside of the side wall and communicating with the axial main airflow channel; and the reinforced mixed turbine interstage combustion chamber further comprises an airflow guide device; the airflow guide device is arranged along the radial direction of the outer shell and is fixed between the outer shell and the inner shell; the airflow guide device is located between an air inlet end of the outer shell and the annular airflow chamber and is hollow inside; an air inlet hole is formed in the side of the airflow guide device facing the air inlet end; and the two side walls of the airflow guide device away from the air inlet end are provided with slits, so that the airflow entering the inside of the airflow guide device from the air inlet hole flows out at the slits and forms radial guide airflow which is perpendicular to the flowing direction of the axial main airflow channel; and the airflow flowing out of the slits is perpendicular to the main airflow, thereby accelerating the mixing and exchange speed between the airflows.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of aero-engine combustion, in particular to a turbine inter-stage combustion chamber with reinforced mixing. BACKGROUND

[0002] In the field of modern aero-engines, the thrust-to-weight ratio is one of the key indicators of performance. In order to improve the thrust-to-weight ratio, the traditional method includes increasing the overall pressure ratio and the turbine inlet temperature. However, due to the development of material technology, the turbine inlet temperature has reached above 1800K, and it is difficult to achieve significant improvement in the short term. Therefore, the afterburning technology has become an alternative solution to improve the thrust, among which the turbine inter-stage combustion chamber (ITB) has attracted attention as a new technology; the turbine inter-stage combustion chamber 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 from the main combustion chamber has a certain temperature drop after passing through the high-pressure turbine, and the heat-resistant strength of the low-pressure turbine has a 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 improving the thrust of the engine. The inter-stage combustion chamber can achieve the purpose of reducing the weight of the engine due to its short axial distance, thereby improving the thrust-to-weight ratio of the engine.

[0003] However, the main problem of the inter-stage combustion chamber is that due to the relatively short axial length, the overall space is relatively limited, and the residence time of the fuel is one order of magnitude shorter than that of the conventional combustion chamber, making it difficult to organize combustion. At the same time, due to space limitations, the temperature distribution at the outlet of the inter-stage combustion chamber is uneven, which will cause the heat intensity of the blades to be uneven and reduce the service life, as the outlet of the inter-stage combustion chamber is the low-pressure turbine.

[0004] Therefore, how to provide a turbine inter-stage combustion chamber that can stably combust under high-temperature and high-speed flow conditions and achieve good outlet temperature distribution is a problem that those skilled in the art need to solve. SUMMARY

[0005] Therefore, the present application provides a turbine inter-stage combustion chamber with reinforced mixing, which aims to solve the above technical problems.

[0006] In order to achieve the above purpose, the present application adopts the following technical solutions:

[0007] A turbine inter-stage combustion chamber with reinforced mixing, comprising an outer shell and an inner shell arranged concentrically, the outer shell and the inner shell having a gap therebetween and forming an axial main airflow passage, the side wall of the outer shell having an annular airflow chamber extending outwardly thereof and communicating with the axial main airflow passage, 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 its interior is hollow. The airflow guide has an air inlet hole on the side 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 interior of the airflow guide from the air inlet hole flows out at the gaps and forms a radial guiding airflow perpendicular to the flow direction of the axial main airflow channel, so as to accelerate the mixing and exchange speed between the axial main airflow channel and the annular airflow chamber.

[0009] Through the above technical solution, the present invention discloses a turbine interstage combustion chamber with enhanced mixing. High-temperature gas flows into the axial main airflow channel. Most of the airflow bypasses the airflow guide and flows along the axial main airflow channel from both sides of the airflow guide. When this part of the airflow flows through the annular airflow chamber, it generates entrainment, introducing part of the airflow into the interior of the annular airflow chamber and generating vortices. 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 near the annular airflow chamber. The airflow flowing out from this gap is perpendicular to the main airflow. The perpendicular flow helps to increase the contact area and interaction between the airflows, thereby accelerating the mixing and exchange speed between the airflows. This is beneficial for introducing the already ignited oil-gas mixture in the annular airflow chamber into the axial main flow channel for complete combustion in the axial main flow channel. It avoids the high-temperature zone from being concentrated near the outer shell of the annular airflow chamber, improves the uniformity of the outlet temperature distribution of the interstage combustion chamber, and extends the life of the low-pressure turbine blades.

[0010] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, 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 formed on the middle plate of the U-shaped plate. A gap exists between the baffle and the open end of the U-shaped plate, forming a radially guided airflow perpendicular to the axial main airflow channel. The design of the U-shaped plate and baffle clarifies the path and method of airflow guidance, enhancing the uniformity of airflow mixing and combustion.

[0011] Preferably, in the aforementioned enhanced mixing turbine interstage combustion chamber, the hollow arrangement of the airflow guide 5 can effectively reduce the overall weight and improve the overall performance of the engine while ensuring strength.

[0012] Preferably, in the aforementioned enhanced mixing interstage combustion chamber, the distance from the sidewall of the annular airflow chamber near the baffle to the intake end is greater than or equal to the distance from the baffle to the intake end. This optimizes the airflow guidance effect, resulting in more uniform radially guided airflow.

[0013] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, the U-shaped plate and the baffle are of equal height. Equal height helps maintain the stability and consistency of the airflow guide structure, ensuring that the airflow from the gap between the U-shaped plate and the baffle flows uniformly to both sides, further optimizing the airflow mixing effect.

[0014] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, the annular airflow chamber has a U-shaped cross-section, and an igniter is installed on its top wall. The ignition end of the igniter passes through the top wall and extends into the inner side of the annular airflow chamber. This facilitates ignition operations within the combustion chamber, improving its reliability and ignition efficiency.

[0015] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, a fuel supply pipe is installed inside the annular airflow chamber, on the side furthest from the intake end, and the fuel supply pipe has multiple injection holes. Installing the fuel supply pipe inside the annular airflow chamber and injecting fuel through multiple injection holes helps to fully mix the fuel and air, improving combustion efficiency and stability. Fuel is supplied only inside the annular airflow chamber, eliminating the need for a fuel supply device on the main flow path, reducing structural complexity, and also preventing ablation of the airflow guide surface.

[0016] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, the injection direction of the fuel injection orifice is opposite to the airflow direction of the axial main airflow channel. This opposite injection direction enhances the mixing effect between fuel and airflow, further improving combustion efficiency.

[0017] Preferably, in the aforementioned enhanced mixing turbine-stage combustion chamber, the included angle between two adjacent fuel injection holes is 12-18°. This helps to achieve uniform fuel distribution and complete combustion, improving the performance and efficiency of the combustion chamber.

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

[0019] This invention improves airflow mixing by using an annular airflow chamber and an airflow guide to direct airflow from the axial direction to the radial direction. This results in a more uniform mixture of fuel and air, leading to a more even distribution of airflow within the combustion chamber. This reduces localized overheating or incomplete combustion, thereby enhancing combustion stability and efficiency. Furthermore, by opening a hole in front of the U-shaped plate, a portion of the airflow passes through the airflow guide and exits through the gap between the U-shaped plate and the rear baffle. This airflow enhances the mixing of the main stream with the airflow within the annular airflow chamber, facilitating the introduction of the already ignited fuel-air mixture from the annular chamber into the main stream for complete combustion. This prevents high-temperature zones from concentrating near the outer shell of the annular airflow chamber, improves the uniformity of the interstage combustion chamber outlet temperature distribution, and extends the lifespan of the low-pressure turbine blades. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 The attached figure is a schematic diagram of the structure of the enhanced mixing turbine interstage combustion chamber provided by the present invention;

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

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

[0024] Figure 4 The attached image is... Figure 3 sectional view of attached figure AA;

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

[0026] in:

[0027] 1-Outer shell;

[0028] 2-Inner shell;

[0029] 3-Axial main airflow channel;

[0030] 4- Annular airflow chamber;

[0031] 5-Airflow guide;

[0032] 51-Air inlet; 52-Gap; 53-U-shaped plate; 54-Baffle;

[0033] 6-Igniter;

[0034] 7-Oil supply pipe. Detailed Implementation

[0035] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0036] Participate in the attached Figures 1-5 This invention discloses an enhanced mixing interstage combustion chamber for turbines, comprising an outer shell 1 and an inner shell 2 arranged concentrically, with a gap between the outer shell 1 and the inner shell 2 forming an axial main airflow channel 3. The outer shell 1 has an annular airflow chamber 4 extending outwards and communicating with the axial main airflow channel on its sidewall, and also includes 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. The airflow guide 5 has an air inlet hole 51 on the side facing the air inlet end. The two side walls of the airflow guide 5 away from the air inlet end have gaps 52, so that the airflow entering the interior of the airflow guide 5 from the air inlet hole 51 flows out at the gaps 52 and forms a radial guiding airflow perpendicular to the flow direction of the axial main airflow channel 3.

[0038] 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] To further optimize the above technical solution, the distance from the side wall of the annular airflow chamber 4 near the baffle 54 to the air inlet is equal to the distance from the baffle 54 to the air inlet.

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

[0041] To further optimize the above technical solution, the width of the opening 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 opening end of the U-shaped plate 53 are the same.

[0042] To further optimize the above technical solution, the cross-section of the annular airflow chamber 4 is U-shaped, 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] To further optimize the above technical solution, an oil supply pipe 7 is installed inside the annular airflow chamber 4, on the side away from the air inlet. The oil supply pipe 7 has multiple oil injection holes. The oil supply pipe 7 is distributed along the circumference and supplies oil through several pipelines through the side of the annular airflow chamber 4 away from the baffle 54.

[0044] To further optimize the above technical solution, the injection direction of the injection hole is opposite to the airflow direction of the axial main airflow channel 3.

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

[0046] The working principle of this invention is as follows:

[0047] High-temperature combustion gas from the high-pressure turbine enters from the intake end. When it reaches the airflow guide 5, most of the airflow bypasses the U-shaped plate 53 and flows past both sides. A small portion of the airflow enters the airflow guide 5 through the intake holes 51 of the U-shaped plate 53. This small portion of the airflow flows out through the gaps 52 on both sides of the airflow guide 5, and the outflow direction is perpendicular to the direction of the mainstream. The annular airflow chamber 4 is the ignition zone, that is, the area where combustion initially occurs. When the mainstream airflow flows through the annular airflow chamber 4, it will generate entrainment, drawing a portion 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 portion of the airflow mixes with the fuel from the injection hole and is then ignited by the igniter 6 to form a flame. Simultaneously, the vortex within the annular airflow chamber 4 also sends the ignited fuel-gas mixture out of the annular airflow chamber 4, merging with the mainstream gas. A low-speed recirculation zone forms behind the baffle 54, causing the high-temperature combustion gas in the annular airflow chamber 4 to flow downwards along the baffle 54, mixing with more mainstream gas in the recirculation zone, ensuring complete combustion and heat release. Because gas flows out through the gap 52 between the U-shaped plate 53 and the rear baffle 54, this gas pushes the mainstream gas to both sides, effectively increasing the width of the baffle 54 and creating a larger recirculation zone, thus 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 transmission from the annular airflow chamber 4 to the mainstream, and make more of the high-temperature gas in the annular airflow chamber 4 be transmitted to the mainstream. This avoids the high-temperature zone at the outlet of the interstage combustion chamber being 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 burned, and extending the life of the entire engine.

[0048] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the apparatus disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the description is relatively simple; relevant parts can be referred to the method section.

[0049] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those 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 invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A turbine-stage combustion chamber with enhanced mixing, comprising a concentrically arranged outer shell (1) and an inner shell (2), wherein a gap exists between the outer shell (1) and the inner shell (2), forming an axial main airflow passage (3), characterized in that, The outer casing (1) has an annular airflow chamber (4) extending outward and communicating with the axial main airflow channel on its side wall, and also includes an airflow guide (5): 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 is hollow inside. The airflow guide (5) has an air inlet hole (51) on the side facing the air inlet end. The two side walls of the airflow guide (5) away from the air inlet end have gaps (52) so that the airflow entering the interior of the airflow guide (5) from the air inlet hole (51) flows out at the gap (52) and forms a radial guiding airflow perpendicular to the flow direction of the axial main airflow channel (3). 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 opening 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 opening 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. The distance from the side wall of the annular airflow chamber (4) near the baffle (54) to the air inlet is equal to the distance from the baffle (54) to the air inlet; The heights of the U-shaped plate (53) and the baffle (54) are equal.

2. The enhanced mixing turbine interstage combustion chamber according to claim 1, characterized in that, The annular airflow chamber (4) has a U-shaped cross-section, 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).

3. The enhanced mixing turbine interstage combustion chamber according to claim 1, characterized in that, An oil supply pipe (7) is installed inside the annular airflow chamber (4) and on the side away from the air inlet. The oil supply pipe (7) has multiple oil injection holes.

4. The enhanced mixing turbine interstage combustion chamber according to claim 3, characterized in that, The injection direction of the injection hole is opposite to the airflow direction of the axial main airflow channel (3).

5. A turbine interstage combustion chamber with enhanced mixing according to claim 4, characterized in that, The included angle between two adjacent injection holes is 12-18°.

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