Afterburner experiment table rear combustion section

Abstract

The invention belongs to the technical field of aero-engine tests, and relates to an afterburner experiment table rear combustion section which is mainly composed of a combustion section casing, a fuel nozzle with a single-stage cyclone, a composite flame stabilizing working unit and an ignition electric nozzle. A swirler I and a swirler II in the composite flame stabilizing working unit are utilized to form a swirling airflow and stable backflow area, and mixed gas in the backflow area is ignited by an ignition electric nozzle; according to the design, the synergistic effect of the swirler combination and the V-shaped evaporation tube flame stabilizer is optimized, and a rear water cooling and tail end spraying system of the combustion section casing is matched, so that efficient and clean combustion of the unburned fuel gas is ensured, the structure is compact, the economical efficiency is good, and the combustion efficiency is high. And the problem of emission treatment of unburned fuel gas in the afterburner test is effectively solved.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a combustion section behind an afterburner test bench. Background Technology

[0002] The afterburner is one of the key components of an aero-engine. During the design process, the lean and rich fuel ignition boundary exploration test is a crucial step. During this test, a large amount of unburned fuel gas is generated. Current testing equipment directly discharges this unburned fuel gas mixture into the exhaust pipe, which then directly into the surrounding atmosphere. Directly releasing this mixture into the atmosphere poses the following hazards: ① The main components of the unburned fuel gas mixture are hydrocarbons, which can harm the health of laboratory personnel; ② With increasingly stringent domestic environmental protection requirements, the unburned fuel gas mixture will cause environmental indicators to exceed standards, making subsequent tests impossible, affecting test efficiency, and increasing test costs; ③ The unburned fuel gas mixture contains a mist of fuel and air, which has a certain degree of flammability, posing a significant safety hazard to the laboratory. Summary of the Invention

[0003] To address the aforementioned problems, this application provides a post-combustion section for an afterburner test bench, applied in an afterburner ignition test system for an aero-engine. The system comprises an afterburner ignition test specimen, an intake system for supplying air to the afterburner ignition test specimen, an exhaust pipe for discharging unburned fuel gas, a post-combustion section for burning the unburned fuel gas in the exhaust pipe, and a fuel system for supplying fuel to the afterburner ignition test specimen and the post-combustion section. The post-combustion section includes: Combustion section casing;

[0004] At least one fuel nozzle with a single-stage cyclone separator is fixed to the combustion chamber casing by a nozzle mounting seat;

[0005] At least one composite flame stabilization unit includes an inner ring, a swirler II fitted outside the inner ring, an outer ring, and a V-shaped evaporator flame stabilizer connected between the outer ring and the swirler II; the V-shaped evaporator flame stabilizer has an inner cylinder fitted on the swirler II; the outer ring is connected to the inner wall of the combustion section casing;

[0006] At least one ignition nozzle is fixed to the combustion section casing via a nozzle mounting bracket;

[0007] The fuel nozzle with a single-stage swirler is inserted into the inner ring of the composite flame stabilization unit, and the discharge end of the ignition nozzle is located near the recirculation zone formed by the fuel nozzle and the composite flame stabilization unit.

[0008] Preferably, the fuel nozzle with single-stage swirler comprises a fuel nozzle and a swirler I sleeved outside the fuel nozzle, the swirler I is clockwise in front view and the pressure loss is designed to be 10%-15%.

[0009] Preferably, the composite stable flame working unit is an integrated structure, the swirler II is counterclockwise in front view and the pressure loss is designed to be 10%-15%.

[0010] Preferably, the V-shaped evaporation tube flame stabilizer forms a V-shaped groove with V-shaped wall surface, the groove opening is backward along the airflow direction, and the V-shaped two walls have air inlet holes distributed along the radial direction of the combustion section.

[0011] Preferably, on the cross section where the combustion section is located, the area ratio formed by the swirler I and the swirler II is less than 40%, the area ratio formed by the V-shaped evaporation tube flame stabilizer is greater than 60%, and the area of the backflow zone is greater than 50% of the total area.

[0012] Preferably, the ignition electrode adopts a water-cooled structure.

[0013] Preferably, the combustion section casing comprises:

[0014] a load-bearing casing;

[0015] a front mounting edge and a rear mounting edge respectively arranged at the front end and the rear end of the load-bearing casing, used for connecting with the pipeline of the test bench;

[0016] a water-cooled casing arranged at the rear half of the load-bearing casing, a cooling water partition plate is arranged between the water-cooled casing and the load-bearing casing, and a cooling water inlet and a cooling water outlet are arranged;

[0017] a plurality of spray water nozzles arranged at the end of the load-bearing casing, and a spray water inlet is arranged.

[0018] Preferably, the cooling water partition plate is provided with slits, the adjacent slits are staggered, and the angle c of the slits is 10°-20°.

[0019] Preferably, the front and rear parts of the load-bearing casing are both provided with wall temperature measuring points, used for controlling the cooling water supply according to the temperature difference.

[0020] Preferably, the V-shaped evaporation tube flame stabilizer, the fuel nozzle and the ignition electrode are arranged in a cross pattern in the circumferential direction.

[0021] The working principle of this invention is that since the ignition test only consumes part of the oxygen in the inlet gas flow, an afterburner section can be added at the end of the exhaust pipe. By supplying fuel, the remaining oxygen in front is used to organize combustion. This burner is designed with lean fuel, which can ignite the unburned fuel gas in front, avoiding the release of unburned fuel gas into the surrounding environment of the laboratory and reducing the harmful effects of unburned fuel gas on human health and environmental safety. Attached Figure Description

[0022] Figure 1 This is a simplified diagram of the afterburner ignition test system;

[0023] Figure 2 This is a schematic diagram of the overall design of the combustion section at the rear of the afterburner test bench;

[0024] Figure 3 This is a schematic diagram of the combustion chamber casing;

[0025] Figure 4 This is a schematic diagram of a composite flame stabilizing working unit;

[0026] Figure 5 This is a schematic diagram of a fuel nozzle with a single-stage cyclone separator.

[0027] Figure 6 This is a schematic diagram of the stabilizer's cross-sectional shape.

[0028] Figure 7 This is a schematic diagram of the circumferential arrangement of the stabilizer, fuel injector, and ignition nozzle.

[0029] Figure 8 This is a schematic diagram of the cooling water baffle structure.

[0030] Figure 9 This is a schematic diagram of an aero-engine afterburner ignition test system.

[0031] 1-Combustion section casing, 2-Fuel nozzle with single-stage swirler, 3-Compound flame stabilization unit, 4-Ignition nozzle, 5-Front mounting edge, 6-Nozzle mounting seat, 7-Cooling water inlet, 8-Nozzle mounting seat, 9-Cooling water outlet, 10-Rear end plate, 11-Spray water inlet, 12-Rear mounting edge, 13-Spray water nozzle, 14-Bearing casing, 15-Front end plate, 16-Water-cooled casing, 17-Cooling water baffle, 18-Outer ring, 19-Swirller II, 20-Inner ring, 21-V-type evaporator flame stabilizer, 22-Fuel nozzle, 23-Swirller I. Detailed Implementation

[0032] For the purpose, technical solutions and advantages of the embodiments of the present application to be clearer, the technical solutions in the embodiments of the present application will be described in more detail below with reference to the drawings in the embodiments of the present application. Identical or similar numerals represent identical or similar elements or elements with identical or similar functions throughout the drawings. The described embodiments are part of the embodiments of the present application, rather than all the embodiments. The embodiments described below with reference to the drawings are exemplary and are intended to explain the present application, and cannot be understood as a limitation of the present application. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative labor fall within the scope of protection of the present application. The embodiments of the present application will be described in detail below with reference to the drawings. As shown in Figure 1 The position of the afterburner in the ignition test system of the afterburner of the aero-engine is shown in the figure. Compressed air enters the afterburner test piece through the air intake system, fuel is pressure-atomized through the fuel injection rod of the afterburner test piece, and is mixed with the surrounding air. When ignition fails or rich oil boundary exploration test is performed, the unburned oil-gas mixture and residual oxygen enter the exhaust pipe. The afterburner is located at the outlet of the exhaust pipe, and uses the residual oxygen in front to ignite and fully burn the unburned oil-gas, forming harmless gas discharged into the atmosphere.

[0033] As shown in Figure 2 The overall scheme of the afterburner of the afterburner test bench is shown in the figure. The afterburner is composed of a combustion chamber case 1, a fuel nozzle with a single-stage swirler 2, a composite flame stabilizing working unit 3 composed of a swirler and a V-shaped evaporation pipe flame stabilizer, and an ignition electrode 4. The main working characteristics are as follows:

[0034] The combustion chamber case 1, as shown in Figure 3 It is the main force structure of the afterburner. The composite flame stabilizing working unit 3, as shown in Figure 4 The outer ring 18 thereof is welded and fixed with the inner wall of the combustion chamber case 1. The fuel nozzle with a single-stage swirler 2, as shown in Figure 5 The mounting flange thereof is assembled and fixed with the nozzle mounting seat 6 on the combustion chamber case 1 by bolts, and the outlet channel I is inserted into the inner ring 20 of the composite flame stabilizing working unit 3. The ignition electrode 4 is assembled and fixed with the electrode mounting seat 8 of the combustion chamber case 1 by bolts.

[0035] The working principle of the combustion section of the afterburner test bench is as follows: Fuel nozzle 22 in fuel nozzle 2 with a single-stage cyclone separator is a single-path centrifugal nozzle with excellent atomization. Unburned fuel gas enters cyclone separator I23, forming a rotating airflow that atomizes the broken fuel into droplets, ensuring thorough mixing to form an oil mist. Simultaneously, the unburned fuel gas passes through cyclone separator II19 in the composite flame stabilization unit 3. The combined effect of these two rotating airflows creates a stable recirculation zone downstream of outlet channel II. A high-energy ignition nozzle 4 can be inserted near the recirculation zone to ignite the fuel-air mixture and ensure stable combustion. A third stream of unburned fuel gas passes through the outer V-shaped evaporator flame stabilizer 21 and enters the subsequent low-speed recirculation zone. It is ignited by the combustion zone formed by cyclone separators I23 and II19, consuming all the fuel in the unburned fuel gas and ultimately forming harmless gas.

[0036] The fuel nozzle 2 with a single-stage cyclone separator consists of a mounting flange, a cyclone separator I23, a fuel nozzle 22, and an outlet channel I. During operation, the fuel nozzle 22 continuously supplies fuel with an adjustable fuel supply rate, ensuring stable combustion while meeting the requirements of different test conditions. The fuel-air ratio in the recirculation zone is designed to be between 0.01 and 0.02. The cyclone separator I23 rotates clockwise in the forward view and employs a high pressure loss design to reduce the probability of backfire; the pressure loss is between 10% and 15%.

[0037] The composite flame stabilizing unit 3 consists of an outer ring 18, an outlet channel II, a cyclone separator II 19, an inner ring 20, and a V-shaped evaporator flame stabilizer 21. It is an integrated structure that can be formed by welding multiple components or by 3D printing. The cyclone separator II 19 rotates counter-clockwise in a forward-looking direction and features a high pressure loss design, with a pressure loss between 10% and 15%. The outlet channel II has an outlet angle of 40° to 50°, creating a large recirculation zone that effectively ignites the surrounding unburned fuel gas. The combustion section design, employing a cyclone separator and a V-shaped evaporator flame stabilizer, allows the cyclone separator to generate a stable ignition source, ensuring stable operation of the combustion section. Furthermore, the evaporator flame stabilizer enhances the atomization of unburned fuel, improving combustion efficiency while reducing the design and manufacturing complexity of the combustion section, thus ensuring its economic viability.

[0038] The V-shaped evaporator flame stabilizer 21 has a slot width of 50-70 mm, such as... Figure 6 As shown, the diameter of the air inlet is selected to be 2-5 mm, the blockage ratio of the cross-section where the flame of the V-shaped evaporator tube is located is selected to be 40-60%, and the number of V-shaped evaporator tube flame stabilizers 21 is determined by the blockage area ratio to the groove width. The groove width and blockage ratio of the V-shaped flame stabilizer are both greater than those of the traditional afterburner, which can improve the stability of the flame and reduce the length of the combustion section.

[0039] The area of the swirler I 23 + swirler II 19 is less than 40% and the area of the V-shaped evaporation tube stabilizer 21 is greater than 60% in the cross section where the combustion section is located. The specific selection can be determined by three-dimensional numerical simulation to ensure that the area of the backflow zone is greater than 50% of the total area.

[0040] The ignition electrode 4 adopts a water-cooled structure, and cooling water can flow in the sleeve to ensure that the ignition electrode 4 is not burned out. This scheme can ensure the insertion depth of the ignition electrode 4 and is more conducive to ignition. The ignition electrode 4 should be deep into the backflow zone formed by the swirler I 23 and the swirler II 19.

[0041] The stabilizer, the fuel nozzle 22 and the ignition electrode 4 are always arranged in a cross arrangement in the circumferential direction, as shown in Figure 7

[0042] The combustion section casing 1 is composed of a front mounting edge 5, a force bearing casing 14, a rear mounting edge 12, a nozzle mounting seat 6, an electrode mounting seat 8, a water-cooled casing 16, a front sealing plate 15, a rear sealing plate 10, a cooling water partition plate 17 and a water spraying nozzle 13, and is welded from stainless steel plates. The processing cost is low. The front and rear mounting edges 5 and 12 are both provided with bolt holes, which are connected with the exhaust pipeline of the test bench. The nozzle mounting seat 6 and the electrode mounting seat 8 are welded on the force bearing casing 14 and used for mounting the fuel nozzle 2 with a single-stage swirler and the ignition electrode 4.

[0043] No cooling structure is arranged in the front half of the combustion section casing 1, because the water-cooled casing 16 and the water spraying cooling are used in the exhaust pipeline of the test bench, and the high-temperature gas flow has been cooled to a temperature below 500℃ or lower. If ignition is unsuccessful, the stainless steel material can meet the use requirements. The rear half of the combustion section casing 1 must be cooled because the combustion chemical reaction exists in the rear combustion section itself. The cooling water enters from the cooling water inlet 7 and flows out from the cooling water outlet 9. The cooling partition plate 17 is arranged between the water-cooled casing 16 and the force bearing casing 14, as shown in Figure 8 The cooling partition plate 17 is provided with notches and arranged in a staggered manner, and the angle c is 10°-20°, which can increase the flow along the way of the cooling water and improve the cooling efficiency. Wall temperature measuring points TA and TB are arranged in the front and rear parts of the force bearing casing 14, and the measuring points are arranged at the middle position of the wall thickness. During operation, the cooling water supply amount is adjusted according to the difference between the two, to ensure that TB-TA<50℃.

[0044] Spraying water is arranged at the end of the combustion section casing 1 to reduce the exhaust temperature. The force bearing casing 14 is provided with 15-20 small holes with a diameter of 16, and the spraying water nozzles 13 are welded on the holes. The spraying water nozzles 13 adopt low-cost finished fan-shaped nozzles or centrifugal nozzles. The purpose of arranging the nozzles is to improve the atomization effect of the spraying water and achieve better cooling effect.

[0045] ​The above merely provides the specific implementation of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can easily think of the changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.

Claims

1. A combustion section behind an afterburner test bench, used in an aero-engine afterburner ignition test system, characterized in that, The system includes an afterburner ignition test specimen, an intake system for supplying intake air to the afterburner ignition test specimen, an exhaust pipe for discharging unburned fuel gas, an afterburner section for burning the unburned fuel gas in the exhaust pipe, and a fuel system for supplying fuel to the afterburner ignition test specimen and the afterburner section, wherein the afterburner section includes: Combustion section casing (1); At least one fuel nozzle (2) with a single-stage cyclone separator is fixed to the combustion chamber casing (1) by a nozzle mounting seat (6); At least one composite flame stabilization unit (3) includes an inner ring (20), a cyclone II (19) sleeved outside the inner ring (20), an outer ring (18), and a V-shaped evaporator flame stabilizer (21) connected between the outer ring (18) and the cyclone II (19); the V-shaped evaporator flame stabilizer (21) has an inner cylinder sleeved on the cyclone II (19); the outer ring (18) is connected to the inner wall of the combustion section casing (1); At least one ignition nozzle (4) is fixed to the combustion section casing (1) by means of a nozzle mounting base (8); The fuel nozzle (2) with a single-stage vortex is inserted into the inner ring (20) of the composite flame stabilization unit (3), and the discharge end of the ignition nozzle (4) is located near the recirculation zone formed by the fuel nozzle (2) and the composite flame stabilization unit (3).

2. The combustion section behind the afterburner test bench according to claim 1, characterized in that, The fuel nozzle (2) with a single-stage swirler includes a fuel nozzle (22) and a swirler I (23) fitted outside the fuel nozzle (22). The swirling direction of the swirler I (23) is forward-looking clockwise, and its pressure loss is designed to be 10% to 15%.

3. The combustion section behind the afterburner test bench according to claim 1, characterized in that, The composite flame stabilizing working unit (3) is an integrally formed structure, and the swirling direction of the cyclone II (19) is forward-looking counterclockwise, with a pressure loss designed to be 10% to 15%.

4. The combustion section behind the afterburner test bench according to claim 3, characterized in that, The V-shaped evaporator flame stabilizer (21) is formed by a V-shaped wall with a V-shaped cross section. The groove opening is directed backward along the airflow direction, and the two walls of the V-shape have air inlet holes distributed radially along the combustion section.

5. The combustion section behind the afterburner test bench according to claim 1, characterized in that, On the cross section where the combustion section is located, the area formed by swirler I (23) and swirler II (19) accounts for less than 40%, the area formed by the V-shaped evaporator flame stabilizer (21) accounts for more than 60%, and the area of ​​the recirculation zone is greater than 50% of the total area.

6. The combustion section behind the afterburner test bench according to claim 1, characterized in that, The ignition nozzle (4) adopts a water-cooled structure.

7. The combustion section behind the afterburner test bench according to claim 1, characterized in that, The combustion section casing (1) includes: Load-bearing casing (14); The front mounting edge (5) and rear mounting edge (12) of the load-bearing casing (14) are respectively set at the front and rear ends for connection with the test bench pipeline; A water-cooled casing (16) is disposed in the rear half of the load-bearing casing (14), and a cooling water baffle (17) is provided between the water-cooled casing (16) and the load-bearing casing (14), and a cooling water inlet (7) and a cooling water outlet (9) are provided; and Multiple spray water nozzles (13) are provided at the end of the load-bearing casing (14), and a spray water inlet (11) is provided.

8. The combustion section behind the afterburner test bench according to claim 7, characterized in that, The cooling water baffle (17) has openings, and adjacent openings are arranged alternately, with the opening angle c being 10° to 20°.

9. The combustion section behind the afterburner test bench according to claim 7, characterized in that, The front and rear parts of the load-bearing casing (14) are equipped with wall temperature measuring points (TA, TB) to control the cooling water supply based on the temperature difference (TB-TA).

10. The combustion section behind the afterburner test bench according to claim 1, characterized in that, The V-shaped evaporator flame stabilizer (21), the fuel nozzle (22), and the ignition nozzle (4) are arranged in a cross pattern in the circumferential direction.

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