Aero-engine core engine exhaust device cooling structure

Abstract

The application provides an aero-engine core engine exhaust device cooling structure, comprising: an outer nozzle ring and an inner nozzle ring; wherein the outer nozzle ring comprises a measuring section casing and a converging section casing, the measuring section casing comprises a measuring section outer casing, a measuring section inner casing and a measuring section orifice plate, the measuring section orifice plate is arranged between the measuring section outer casing and the measuring section inner casing; the converging section casing comprises a converging section outer casing and a converging section inner casing, the converging section outer casing and the converging section inner casing are arranged at the rear side of the measuring section casing, and the converging section outer casing and the converging section inner casing have a radial distance therebetween; the inner nozzle ring comprises an inner ring outer casing, an inner ring inner casing, an inner ring orifice plate and a heat shield, the inner ring orifice plate is arranged between the inner ring outer casing and the inner ring inner casing; and the heat shield is arranged at the end of the inner ring inner casing and is used for dividing the inner side cavity of the inner ring into two parts to prevent high-temperature gas of a main flow channel from pouring into the inner side chamber of the inner nozzle casing from the rear side.

Description

A cooling structure for the exhaust system of an aero-engine core. Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a cooling structure for the exhaust device of an aero-engine core. Background Technology

[0002] Unlike the complete aero-engine, the core engine test engine does not include the low-pressure turbine. Therefore, the exhaust temperature of the core engine is much higher than that of the complete engine. During core engine testing, the ambient temperature of the exhaust system is comparable to the high-pressure turbine outlet temperature in the complete engine configuration. The main function of the core engine exhaust system is to construct the exhaust channel through the inner and outer rings of the nozzle, ensuring the effectiveness of the core engine exhaust area and providing crucial information for judging core engine performance indicators. With the continuous increasing demands on aero-engines, the core engine exhaust temperature has far exceeded the service limits of metallic material structures. To ensure the safety of the core engine test engine, appropriate temperature resistance or cooling measures are required for the core engine exhaust system.

[0003] There are two main types of exhaust systems for core engines. The first type is a metal exhaust system, which uses conventional forced convection heat transfer for cooling. However, at a certain core engine test state, the heat transfer coefficient on the cold side of the exhaust system is on the order of 100 W / (m2.K), while the heat transfer coefficient on the hot side of the main flow channel is on the order of 1000 W / (m2.K), a difference of one order of magnitude. Under this cooling method, the wall temperature of the exhaust system is basically equivalent to the temperature of the main flow channel of the combustion gas, posing a significant risk of overheating. The second type is a ceramic-based exhaust system. This type of exhaust system uses the same cooling method as the first type, but the first type of exhaust system has a high risk of overheating, so the material has been improved. However, ceramic-based materials face problems such as high cost and long processing cycle. Summary of the Invention

[0004] The purpose of this application is to provide a cooling structure for the exhaust system of an aero-engine core to solve or mitigate at least one of the problems in the prior art.

[0005] The technical solution of this application is: a cooling structure for the exhaust device of an aero-engine core engine, the cooling structure for the exhaust device of the core engine comprising: an outer ring of the nozzle and an inner ring of the nozzle;

[0006] The nozzle outer ring includes a measuring section casing and a converging section casing. The measuring section casing includes an outer measuring section casing, an inner measuring section casing, and a measuring section orifice plate. The measuring section orifice plate is disposed between the outer measuring section casing and the inner measuring section casing, forming a measuring section gas collection chamber between the outer measuring section casing and the measuring section orifice plate. The measuring section orifice plate has a full circle of airflow holes distributed along the airflow direction. The cooling gas in the measuring section gas collection chamber impacts and cools the inner measuring section casing through the airflow holes. The converging section casing includes an outer converging section casing and an inner converging section casing. The outer converging section casing and the inner converging section casing are disposed on the rear side of the measuring section casing. There is a radial distance between the outer converging section casing and the inner converging section casing. The gap forms a converging section interlayer cavity that communicates with the measuring section gas collection chamber.

[0007] The nozzle inner ring includes an inner outer casing, an inner inner casing, an inner orifice plate, and a heat shield. The inner orifice plate is disposed between the inner outer casing and the inner inner casing, thereby forming a cooling channel between the inner outer casing and the inner orifice plate. Cooling gas entering the inner ring intake chamber enters the cooling channel to cool the inner outer casing. The heat shield is disposed at the end of the inner inner casing and is used to divide the inner cavity of the inner ring into two parts to prevent high-temperature gas from the main flow channel from entering the inner cavity of the nozzle inner ring casing from the rear.

[0008] In a preferred embodiment of this application, the distance between the measuring section orifice plate and the outer casing of the measuring section is greater than the distance between the measuring section orifice plate and the inner casing of the measuring section.

[0009] In a preferred embodiment of this application, the radial distance between the outer casing and the inner casing of the convergence section is as small as possible to improve the cooling effect of the convergence section casing.

[0010] In a preferred embodiment of this application, the inner annular plate is T-shaped and includes a main body extending axially and a support extending radially, the support being used to support the main body.

[0011] In a preferred embodiment of this application, the support portion divides the cavity between the inner ring perforated plate and the inner ring inner casing into a front impact cavity and a rear impact cavity, which can uniformly distribute the cooling gas to the axial front and rear ends of the outer casing of the inner ring.

[0012] In a preferred embodiment of this application, the axial dimension of the inner ring casing of the nozzle is shortened as much as possible while ensuring that the exhaust area of ​​the core machine remains unchanged.

[0013] The core engine exhaust device cooling structure provided in this application changes the cooling method of the exhaust device from forced convection heat transfer to impact cooling, which effectively improves the cooling effect of the hot end components of the exhaust device; by increasing the cooling of the nozzle convergent section casing, the effectiveness of the core engine exhaust area is ensured, providing an important basis for judging the core engine performance indicators; the exhaust device cooling structure is made of metal materials, which can effectively reduce the core engine production and processing costs compared with ceramic-based exhaust devices. Attached Figure Description

[0014] To more clearly illustrate the technical solutions provided in this application, the accompanying drawings will be briefly described below. Obviously, the drawings described below are merely some embodiments of this application.

[0015] Figure 1 is a schematic diagram of the cooling structure of a conventional core engine exhaust system.

[0016] Figure 2 is a schematic diagram of the cooling structure of the core machine exhaust device in this application. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings.

[0018] In order to overcome the problems that existing exhaust devices using metal materials can reduce the production and processing costs of the core engine, but the cooling effect of the exhaust device is poor, and the hot end components of the exhaust device are not easy to open to avoid backflow of gas due to the constraints of the exhaust position and bleed air pressure and bleed air volume of the core engine, this application provides a novel cooling structure for the exhaust device of the aero-engine core engine.

[0019] Figure 1 shows a schematic diagram of the cooling structure of a conventional core engine exhaust system. This conventional core engine exhaust system 10 consists of two parts: an outer nozzle ring 10A and an inner nozzle ring 10B. The outer nozzle ring 10A includes a measuring section casing and a converging section casing. The measuring section casing consists of an outer measuring section casing 11 and an inner measuring section casing 12, while the converging section casing consists of an outer converging section casing 13 and an inner converging section casing 14. The inner nozzle ring 10B consists of an outer inner ring casing 15 and an inner inner ring casing 16. The main flow path between the inner and outer nozzle rings is a high-temperature, high-pressure, high-speed airflow. The inner measuring section casing 12, the inner converging section casing 14, and the outer inner ring casing 15 of the exhaust system are in direct contact with the combustion gas and require effective cooling.

[0020] Referring to Figure 1, which shows a typical chamber of the cooling structure of the exhaust device of a conventional core engine, the cooling gas of the outer ring of the nozzle enters the chamber Q1 from the outer casing 11 of the measuring section through the intake pipe, cools the inner casing 12 of the measuring section, and then is discharged to the atmosphere from the outer casing 11 of the measuring section through the exhaust pipe.

[0021] In the inner ring of the nozzle, the cooling gas from the gas collecting chamber Q3 cools the outer casing 15 of the inner ring through the interlayer cavity between the inner and outer ring casings, and is then discharged to the atmosphere from the exhaust chamber Q4. The mixed gas used in the core engine for disk cooling, pivot sealing, etc., enters the inner cavity Q5 and is discharged to the atmosphere from the exhaust chamber Q6.

[0022] However, in conventional exhaust cooling structures, the measuring section casing of the outer ring 10A of the nozzle and the casing of the inner ring 10B of the nozzle both use forced convection heat transfer. Under this cooling method, the wall temperature of the exhaust device is basically equivalent to the temperature of the main gas flow channel, which poses a great risk of overheating. Furthermore, the casing of the nozzle converging section is not cooled in an organized manner, which can easily cause the casing to deform due to heat, resulting in changes in the exhaust area of ​​the core engine and directly affecting the performance of the core engine.

[0023] To overcome the above problems, this application provides an improved cooling structure for the core engine exhaust device. Based on the improved cooling structure, a measuring section orifice plate and an inner ring orifice plate are added to the outer ring and inner ring of the nozzle, respectively. The cooling method of the measuring section casing of the outer ring of the nozzle and the inner ring of the nozzle is changed from forced convection heat transfer to impingement cooling. At the same time, the cooling of the converging section casing of the nozzle is also added.

[0024] Figure 2 shows a schematic diagram of the improved core engine exhaust device cooling structure. The improved core engine exhaust device cooling structure 20 includes: an outer ring 20A of the nozzle and an inner ring 20B of the nozzle.

[0025] The nozzle outer ring 20A includes a measuring section casing and a convergent section casing. The measuring section casing includes a measuring section outer casing 21, a measuring section inner casing 22, and a measuring section orifice plate 23. The convergent section casing includes a convergent section outer casing 24 and a convergent section inner casing 25.

[0026] The measuring section orifice plate 23 is disposed between the measuring section outer casing 21 and the measuring section inner casing 22, forming a measuring section gas collecting cavity K1 between the measuring section outer casing 21 and the measuring section orifice plate 23, and an impact cooling channel between the measuring section inner casing 22 and the measuring section orifice plate 23. The measuring section orifice plate 23 has a full circle of airflow holes distributed along the airflow direction, and the cooling gas in the measuring section gas collecting cavity K1 impacts and cools the measuring section inner casing 22 through the airflow holes. In a preferred embodiment of this application, to ensure the impact cooling effect, the distance between the measuring section orifice plate 23 and the measuring section outer casing 21 is greater than the distance between the measuring section orifice plate 23 and the measuring section inner casing 22.

[0027] The outer casing 24 and the inner casing 25 of the convergence section are disposed behind the measuring section casing. A certain radial distance exists between the outer casing 24 and the inner casing 25, forming a convergence section interlayer cavity K2, which communicates with the measuring section gas collecting cavity K1. In a preferred embodiment of this application, to improve the cooling effect of the convergence section casing, the radial distance between the outer casing 25 and the inner casing 25 is minimized as much as possible. For example, in some embodiments of this application, this radial distance can be 0.1 mm to 1 mm.

[0028] The nozzle inner ring 20B includes an inner ring outer casing 26, an inner ring inner casing 27, an inner ring orifice plate 28, and a heat shield 29. The inner ring orifice plate 28 is disposed between the inner ring outer casing 26 and the inner ring inner casing 27, thereby forming a small cooling channel between them. Cooling gas entering the inner ring intake chamber K3 can enter this cooling channel to cool the inner ring outer casing 26.

[0029] In a preferred embodiment of this application, the inner ring perforated plate 28 is T-shaped, comprising a main body extending axially and a support portion 281 extending radially, the support portion 281 supporting the main body. The cooling channel is located between the main body and the inner ring outer casing 26. Multiple vent holes are distributed axially on the main body, allowing cooling gas to enter the cooling channel through these vent holes, achieving impact cooling of the inner ring outer casing 26. The support portion 281 divides the cavity between the inner ring perforated plate 28 and the inner ring inner casing 27 into a front impact cavity K4 and a rear impact cavity K5. Cooling gas flowing into the inner ring inlet cavity K3 impacts the front cavity K4 and flows out through the vent holes, achieving impact cooling of the front end of the inner ring outer casing 26. Then, it flows along the cooling channel and vent holes into the rear impact cavity K5 and flows out again through the rear vent holes, achieving impact cooling of the rear end of the inner ring outer casing 26. Ultimately, this ensures that the cooling gas is evenly distributed to the front and rear ends of the inner ring outer casing 26 axially.

[0030] The heat shield 29 is located at the end of the inner ring inner casing 27 and is used to divide the inner ring inner cavity K7 into two parts to prevent the high-temperature gas in the main channel from entering the inner cavity of the nozzle inner ring casing from the rear.

[0031] In a preferred embodiment of this application, in order to increase the cooling effect of the nozzle inner ring with limited cooling capacity, the axial dimension of the nozzle inner ring casing can be shortened while ensuring that the exhaust area of ​​the core machine remains unchanged.

[0032] When the core engine exhaust cooling structure of this application is in operation, the cooling gas from the outer ring 20A of the nozzle enters the gas collecting chamber K1 of the measuring section from the circumferential pipeline of the outer casing 11 of the measuring section. After cooling the inner casing 22 of the measuring section through the vent holes of the measuring section orifice plate 23, it flows axially into the convergent section interlayer cavity K2 of the convergent section casing, further cooling the inner casing 25 of the convergent section, and then is discharged to the atmosphere from the end of the convergent section interlayer cavity K2. In the inner ring 20B of the nozzle, the cooling gas from the inner ring intake cavity K3 cools the outer casing 26 of the inner ring through the vent holes of the inner ring orifice plate 28, and then is discharged to the atmosphere from the exhaust chamber K6 along the cooling channel. The mixed gas used in the core engine for disk cooling, pivot sealing, etc., enters the inner ring inner cavity K7, and is discharged to the atmosphere from the exhaust chamber K6 through the exhaust holes on the heat shield. Regarding the cooling of the inner ring outer casing 26, due to the influence of airflow ejection, and because the pressure of the exhaust chamber K6 is lower than atmospheric pressure, in order to ensure that the cooling air is evenly distributed to the front and rear ends of the inner ring outer casing, a flow path is formed by connecting the upstream and downstream of the front impact chamber K4 and the rear impact chamber K5. Under the premise of ensuring that the exhaust area of ​​the core machine remains unchanged, the cooling effect of the hot end components of the exhaust device can be effectively improved.

[0033] The core engine exhaust device cooling structure provided in this application changes the cooling method of the exhaust device from forced convection heat transfer to impact cooling, which effectively improves the cooling effect of the hot end components of the exhaust device; by increasing the cooling of the nozzle convergent section casing, the effectiveness of the core engine exhaust area is ensured, providing an important basis for judging the core engine performance indicators; the exhaust device cooling structure is made of metal materials, which can effectively reduce the core engine production and processing costs compared with ceramic-based exhaust devices.

[0034] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A cooling structure for the exhaust system of an aero-engine core, characterized in that, The core engine exhaust cooling structure includes: an outer nozzle ring (20A) and an inner nozzle ring (20B); wherein, the outer nozzle ring (20A) includes a measuring section housing and a converging section housing, the measuring section housing includes a measuring section outer housing (21), a measuring section inner housing (22), and a measuring section orifice plate (23), the measuring section orifice plate (23) is disposed between the measuring section outer housing (21) and the measuring section inner housing (22), so that the measuring section outer housing... A measuring section gas collecting chamber (K1) is formed between the casing (21) and the measuring section orifice plate (23). The measuring section orifice plate (23) has a full circle of airflow holes distributed along the airflow direction. The cooling gas in the measuring section gas collecting chamber (K1) impacts and cools the measuring section inner casing (22) through the airflow holes. The convergence section casing includes a convergence section outer casing (24) and a convergence section inner casing (25). The convergence section outer casing (24) and the convergence section inner casing (25) are provided with The outer casing (24) of the convergent section and the inner casing (25) of the convergent section are located on the rear side of the measuring section casing, and there is a radial distance between them. The distance forms a convergent section interlayer cavity (K2) that communicates with the gas collection chamber (K1) of the measuring section. The nozzle inner ring (20B) includes an outer casing (26), an inner casing (27), an inner orifice plate (28), and a heat shield (29). The inner orifice plate (28) is disposed between the outer casing (26) and the inner casing (29). (27) and thus a cooling channel is formed between the inner ring outer casing (26) and the inner ring perforated plate (28). The cooling gas entering the inner ring intake chamber (K3) enters the cooling channel to cool the inner ring outer casing (26). The heat shield (29) is set at the end of the inner ring inner casing (27) to divide the inner ring inner cavity (K7) into two parts to prevent the high temperature gas of the main channel from entering the inner cavity of the nozzle inner ring casing from the rear.

2. The cooling structure for the exhaust system of the aero-engine core as described in claim 1, characterized in that, The distance between the measuring section orifice plate (23) and the measuring section outer casing (21) is greater than the distance between the measuring section orifice plate (23) and the measuring section inner casing (22).

3. The cooling structure for the exhaust system of the aero-engine core as described in claim 1, characterized in that, The radial distance between the outer casing (25) and the inner casing (25) of the convergence section is as small as possible to improve the cooling effect of the convergence section casing.

4. The cooling structure for the exhaust system of the aero-engine core as described in claim 1, characterized in that, The inner ring plate (28) is T-shaped and includes a main body extending axially and a support (281) extending radially, the support (281) being used to support the main body.

5. The cooling structure for the exhaust system of the aero-engine core as described in claim 4, characterized in that, The support (281) divides the cavity between the inner ring perforated plate (28) and the inner ring inner casing (27) into an impact front cavity (K4) and an impact rear cavity (K5), which can evenly distribute the cooling gas to the axial front and rear ends of the inner ring outer casing (26).

6. The cooling structure for the exhaust system of the aero-engine core as described in claim 1, characterized in that, While keeping the exhaust area of ​​the core engine unchanged, the axial dimension of the nozzle inner ring casing should be shortened as much as possible.

7. The cooling structure for the exhaust system of an aero-engine core as described in any one of claims 1 to 6, characterized in that, Both the outer ring (20A) and the inner ring (20B) of the nozzle are made of metal.

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