Intelligent flame-out combustion chamber and method of ignition

Abstract

The application belongs to the technical field of gas turbine engines, and provides a combustion chamber with intelligent point flameout and an ignition method, which comprises: a diffuser connected with a machine case; a flame tube is installed in the machine case, the flame tube has a backflow area in the inside, and the backflow area is surrounded by a high-speed shear layer; an ignition system comprises an ignition electrode; when the flame tube is ignited, or when the pressure in the flame tube is lower than a preset value, or when the pressure change rate in the flame tube exceeds a preset range, the ignition electrode moves to the backflow area through the high-speed shear layer. The combustion chamber has an electromagnetic / pneumatic force coupled ignition system, the ignition position is moved from the high-speed shear layer to the backflow area, thereby being beneficial to flame stabilization, the generation probability of an initial flame core can be greatly improved, and due to the fact that the initial flame core is located in the backflow area, the propagation distance of the initial flame core can be significantly shortened or even eliminated, and the engine ignition envelope range can be greatly widened.

Description

Technical Field

[0001] This invention belongs to the field of gas turbine engine technology, and specifically relates to a combustion chamber with intelligent ignition and shutdown and an ignition method. Background Technology

[0002] The existing low-emission lean-fuel central staged combustion chamber mainly consists of a casing 2, a flame tube 3, an ignition electrode 801, and an ignition device 12, etc. (e.g.) Figure 1 As shown), its function in the engine is to burn fuel, converting the chemical energy in the fuel into thermal energy, increasing the total enthalpy of the air entering the combustion chamber, and turning it into combustion gas to drive the gas turbine to do work. The specific working process is as follows: High-pressure air compressed by the compressor enters the combustion chamber through the diffuser, and then the air is divided into three streams, entering the head, outer ring channel and inner ring channel respectively. Most of the gas enters the flame tube through the main combustion stage swirl and pre-combustion stage swirl in the head; fuel enters the flame tube through the fuel nozzle, mixes with the high-pressure air in the flame tube and flows with it; when the combustion chamber is ignited, the electric spark generated by the ignition nozzle located near the flame tube wall ignites the fuel-air mixture in the vicinity, producing a flame core 11; the flame core 11 propagates and ignites the fuel-air mixture in the recirculation zone, forming a stable flame, thus achieving successful ignition; in the normal working state of the combustion chamber, the high-temperature combustion gas generated in the combustion chamber enters the turbine along the axial direction, driving it to do work.

[0003] The existing technical solutions have the following three main drawbacks: 1. To ensure low NOx emissions, the air intake at the head of the lean central staged combustor increases dramatically, from about 20% in a conventional combustor to 70% or more, significantly reducing the air-fuel ratio at the head. The main combustion stage accounts for a large proportion of the air intake at the head, resulting in a high-speed shear layer downstream. The airflow velocity near the ignition nozzle outlet is typically very high, making it difficult for the fuel from the fuel nozzle to reach the area near the ignition nozzle outlet. These three factors usually make it difficult for the flame core (11) to form. 2. The chamber height of this type of combustor is usually much greater than that of a conventional combustor, increasing the distance the flame core (11) travels from near the ignition nozzle outlet to the recirculation zone. Simultaneously, the presence of the high-speed shear layer increases the difficulty of traversing the propagation path. These two factors significantly reduce the probability of the initial flame core successfully propagating into the recirculation zone. 3. The main combustion zone within the combustor is primarily used to maintain flame stability. However, the large proportion of air intake at the head of the central staged combustor leads to a significantly reduced air-fuel ratio in the main combustion zone and a narrow lean flameout boundary, making flameout accidents more likely, especially under extreme aircraft maneuvering conditions. 4. In the design of this type of combustion chamber, in order to ensure the ignition performance of the combustion chamber, there are usually many restrictions on the gas-to-air ratio of the main combustion stage and the pre-combustion stage, the step height of the main combustion stage and the pre-combustion stage, the insertion depth of the fuel nozzle and the mist cone angle, which limit the potential for further reduction of NOx emissions. Summary of the Invention

[0004] To address at least one of the problems in the background art, the present invention proposes a combustion chamber with intelligent ignition and shutdown.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A combustion chamber with intelligent flameout capability, comprising:

[0007] The diffuser connects to the housing;

[0008] The casing is equipped with a flame tube, and the flame tube has a recirculation zone inside, with a high-speed shear layer surrounding the recirculation zone.

[0009] Ignition system, including ignition source;

[0010] When the flame tube is ignited, or when the pressure inside the flame tube is lower than a preset value, or when the rate of change of pressure inside the flame tube exceeds a preset range, the ignition nozzle moves through the high-speed shear layer to the recirculation zone.

[0011] Preferably, the diffuser has an inner diameter that gradually increases in the direction toward the casing.

[0012] Preferably, the casing is connected to one end of the flame tube.

[0013] Preferably, the end of the flame tube facing the diffuser is provided with a plurality of pre-combustion air inlets and a plurality of main combustion air inlets;

[0014] The pre-combustion air inlet is located inside the main combustion air inlet;

[0015] Both the pre-combustion air inlet and the main combustion air inlet are located at the inlet of the flame tube;

[0016] The air intake ratio between the pre-combustion air intake and the main combustion air intake is 15:1;

[0017] The area between the pre-combustion air inlet and the main combustion air inlet is a platform stage, the height of which is 5% to 30% of the height of the flame tube cavity.

[0018] Preferably, a pre-combustion stage vortex generator is installed in the pre-combustion intake port, and a main combustion stage vortex generator is installed in the main combustion intake port.

[0019] Preferably, a fuel nozzle is also installed at the end of the flame tube facing the diffuser, and the fuel nozzle is located at the end of the flame tube facing the diffuser;

[0020] The fuel nozzle has a mist cone angle of 0 to 150°.

[0021] Preferably, in the ignition system, a permanent magnet is provided at the end of the ignition nozzle away from the flame tube, and the permanent magnet drives the ignition nozzle to slide radially along the flame tube;

[0022] An electromagnet is installed on the side of the permanent magnet away from the flame tube, and the electromagnet is stationary relative to the flame tube.

[0023] When the electromagnet is energized, the S pole or N pole of the electromagnet and the permanent magnet are positioned facing each other.

[0024] Preferably, both the ignition nozzle and the electromagnet are connected to an ignition device, which is used to detect the air pressure inside the casing and control the working state of the ignition nozzle and the electromagnet based on the air pressure.

[0025] An ignition method for use in the aforementioned intelligent ignition and extinguishing combustion chamber.

[0026] Preferably, the ignition method includes the following steps:

[0027] When the combustion chamber is ignited, or when the internal air pressure of the casing is detected to be lower than the preset value, or when the rate of change of the internal air pressure of the casing is detected to exceed the preset range, the electromagnet in the ignition system is energized to cause the electromagnet to repel the permanent magnet in the ignition system.

[0028] The magnetic repulsive force of the permanent magnet is greater than the thrust of the compressed air entering the casing, which in turn drives the ignition nozzle from the high-speed shear layer to the recirculation zone.

[0029] When the electromagnet is de-energized, the compressed air entering the casing pushes the ignition nozzle from the recirculation zone to the high-speed shear layer.

[0030] The beneficial effects of this invention are:

[0031] 1. The combustion chamber features an innovative electromagnetic / aerodynamic coupling ignition system that moves the ignition position from the high-speed shear layer to the recirculator, which is beneficial to flame stability and can greatly increase the probability of initial fire core generation. At the same time, since the initial fire core is located in the recirculator zone, the propagation path of the initial fire core can be significantly shortened or even eliminated, greatly expanding the engine ignition envelope.

[0032] 2. The combustion chamber adopts an ignition system. The ignition device detects the gas pressure data in the combustion chamber and then controls the position of the ignition nozzle to automatically provide additional energy to the combustion chamber, maintain flame stability, and prevent the combustion chamber from going out.

[0033] 3. Finally, the innovative design of the central staged combustion chamber structure and aerodynamics brought about by the new ignition system: 1. The combustion chamber design can adopt a more flexible gas-air ratio distribution design between the main combustion stage and the pre-combustion stage, which can be widened from the original 3-6 to 1-15; 2. The combustion chamber design can adopt a more flexible step height design between the main combustion stage and the pre-combustion stage, which can be widened from 8%-12% of the flame tube height to 5%-30% of the flame tube height; 3. The combustion chamber design can adopt a more flexible pre-combustion stage fuel nozzle design, and the nozzle mist cone angle can be widened from the original 80°-150° to 0°-150°.

[0034] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0035] 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 some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0036] Figure 1 A schematic diagram of the structure of an existing ignition-extinguishing exhaust combustion chamber is shown;

[0037] Figure 2 A schematic diagram of the structure of a combustion chamber with intelligent ignition and shutdown according to the present invention is shown.

[0038] In the diagram: 1. Diffuser; 2. Casing; 3. Flame tube; 301. Pre-combustion air inlet; 302. Main combustion air inlet; 4. Main combustion stage vortex generator; 5. Pre-combustion stage vortex generator; 6. Stage; 7. Fuel nozzle; 8. Ignition system; 801. Ignition electrode; 9. Electromagnet; 10. Permanent magnet; 11. Flame core; 12. Ignition device. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, 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, 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.

[0040] A combustion chamber with intelligent flameout, such as Figure 2As shown, it includes a diffuser 1, a housing 2, a flame tube 3, and an ignition system 8. The diffuser 1 is fixedly connected to one end of the housing 2, for example, by welding. In addition, both the diffuser 1 and the housing 2 are annular structures, and the inner diameter of the diffuser 1 gradually increases along the direction towards the housing 2.

[0041] Furthermore, the flame tube 3 is installed inside the casing 2, with one end connected to the casing 2, ensuring its stability and reliability under various operating conditions. The end of the flame tube 3 facing the diffuser 1 is provided with several pre-combustion inlets 301 and several main combustion inlets 302. The pre-combustion inlets 301 are located inside the main combustion inlets 302, and both the pre-combustion inlets 301 and the main combustion inlets 302 are located at the inlet of the flame tube 3. In addition, a pre-combustion stage vortex generator 5 is installed inside the pre-combustion inlet 301, and a main combustion stage vortex generator 4 is installed inside the main combustion inlet 302. These vortex generators significantly improve the air-fuel mixing efficiency by generating a strong vortex effect, further enhancing engine performance and fuel economy. A fuel nozzle 7 is also installed at the end of the flame tube 3 facing the diffuser 1. The fuel nozzle 7 is located at the end of the flame tube 3 facing the diffuser 1. The pre-combustion air inlet 301 is located inside the fuel nozzle 7, and the main combustion air inlet 302 is located outside the fuel nozzle 7. The position of the nozzle has been precisely calculated and optimized to ensure that the fuel can be injected into the combustion chamber in the best way and perfectly combined with the pre-combustion air, thereby achieving the maximum thermal energy conversion efficiency.

[0042] It should be noted that stage 6 is located between the pre-combustion inlet 301 and the main combustion inlet 302. Stage 6 effectively controls the distance between the two inlets. After compressed air enters the casing 2, the air-to-air ratio between the main combustion stage and the pre-combustion stage can be widened from the original 3-6 to 1-15. The combustion chamber design allows for a more flexible step height (stage) design between the main combustion stage and the pre-combustion stage, widening from 8%-12% of the chamber height to 5%-30%. The combustion chamber design also allows for a more flexible nozzle design, widening the nozzle cone angle from the original 80°-150° to 0°-150°.

[0043] It should be further explained that the specific working process of the combustion chamber is as follows: the high-pressure air compressed by the compressor enters the casing 2 through the diffuser 1, and then the air is divided into three streams, which enter the head, the outer ring channel and the inner ring channel respectively. Most of the gas passes through the main combustion stage vortex 4 in the head, and a small amount of gas enters the flame tube 3 through the pre-combustion stage vortex 5. The fuel enters the flame tube through the fuel nozzle 7, mixes with the high-pressure air in the flame tube 3 and flows with it.

[0044] Furthermore, in Figure 2In the combustion chamber, fuel is injected into the flame tube 3 through the fuel nozzle 7 during operation. At the same time, air is introduced into the flame tube 3 at positions A and B respectively. The air introduced at position A mixes with the fuel to form a fuel-air mixture, which plays a pre-combustion role. The air introduced at position B mixes with the fuel to form a fuel-air mixture, which enters the main combustion zone.

[0045] It should be noted that the air flow within the flame tube 3 creates a high-speed shear layer and a recirculation zone, specifically as follows: Figure 2 As shown, the reflux region ( Figure 2 The middle D region is located downstream of the fuel nozzle 7 and inside the flame tube 3, where the high-speed shear layer ( Figure 2 The C region is located on the periphery of the reflux zone.

[0046] It should be further noted that the rotation center of flame tube 3 is located at Figure 2 The outer side of the middle casing 2.

[0047] Furthermore, the ignition system 8 includes an ignition nozzle 801; when the flame tube 3 is ignited, or when the pressure inside the flame tube 3 is lower than a preset value, or when the pressure change rate inside the flame tube 3 exceeds a preset range, the ignition nozzle 801 is used to move from the high-speed shear layer to the recirculation zone. Specifically, in the ignition system 8, a permanent magnet 10 is provided at the end of the ignition nozzle 801 away from the flame tube 3, and the permanent magnet 10 drives the ignition nozzle 801 to slide radially along the flame tube 3; an electromagnet 9 is installed on the side of the permanent magnet 10 away from the flame tube 3, and the electromagnet 9 is stationary relative to the flame tube 3; when the electromagnet 9 is energized, the S pole or N pole of the electromagnet 9 and the permanent magnet 10 are positioned facing each other.

[0048] It should be noted that both the ignition nozzle 801 and the electromagnet 9 are connected to an ignition device 12. The ignition device 12 is used to detect the air pressure inside the casing 2 and control the operating state of the ignition nozzle 801 and the electromagnet 9 based on the air pressure. For example, in Figure 2 In the middle, the ignition device 12 detects the internal air pressure at position E inside the casing 2.

[0049] An ignition method for the aforementioned intelligent ignition and shutdown combustion chamber includes the following three cases:

[0050] In the first scenario: when the combustion chamber is ignited, the electromagnet 9 in the ignition system 8 is energized, causing the electromagnet 9 to repel the permanent magnet 10 in the ignition system 8. Then, the repulsive force of the magnetic field is greater than the thrust of the compressed air entering the casing 2, thereby driving the ignition nozzle 801 from the high-speed shear layer to the recirculation zone. When the electromagnet 9 is de-energized, the interaction of the magnetic fields disappears, and the compressed air entering the casing 2 pushes the ignition nozzle 801 from the recirculation zone to the high-speed shear layer.

[0051] The second scenario: When the combustion chamber is ignited, the ignition device 12 connected to the ignition nozzle 801 detects the internal air pressure of the casing 2. When the internal air pressure of the casing 2 is lower than the preset value, the electromagnet 9 in the ignition system 8 is energized, causing the electromagnet 9 to repel the permanent magnet 10 in the ignition system 8. Then, the permanent magnet 10 drives the ignition nozzle 801 from the high-speed shear layer to the recirculation zone through the magnetic field repulsion (at this time, the magnetic force is greater than the thrust of the compressed air). When the electromagnet 9 is de-energized, the interaction of the magnetic fields disappears, and the compressed air entering the casing 2 pushes the ignition nozzle 801 from the recirculation zone to the high-speed shear layer.

[0052] The third scenario: When the combustion chamber is ignited, the ignition device 12 connected to the ignition nozzle 801 detects the internal air pressure of the casing 2. When the pressure change rate inside the casing 2 exceeds the preset range, the electromagnet 9 in the ignition system 8 is energized, causing the electromagnet 9 to repel the permanent magnet 10 in the ignition system 8. Then, the permanent magnet 10 drives the ignition nozzle 801 from the high-speed shear layer to the recirculation zone through the magnetic field repulsion (at this time, the magnetic force is greater than the thrust of the compressed air). When the electromagnet 9 is de-energized, the interaction of the magnetic fields disappears, and the compressed air entering the casing 2 pushes the ignition nozzle 801 from the recirculation zone to the high-speed shear layer.

[0053] It should be noted that when the combustion chamber is ignited, the ignition device 12 supplies power to the electromagnet 9 and the ignition nozzle 801 respectively. The mutual repulsion force generated by the electromagnet 9 and the permanent magnet 10 is greater than the aerodynamic force generated by the pressure difference between the inside and outside, causing the ignition nozzle 801 to move into the flame tube 3 to the set position, and then ignite to generate the flame core 11. The electric spark generated by the ignition nozzle 801 ignites the oil-gas mixture in the nearby area to form a stable flame, and the combustion chamber is successfully ignited.

[0054] When the pressure inside the combustion chamber is low (at ground idle or minimum air condition) or the pressure change rate is large, the ignition device 12 supplies power to the electromagnet 9 and the ignition nozzle 801 respectively. The ignition nozzle 801 automatically moves to the central recirculation zone inside the flame tube 3 to provide additional energy to the combustion chamber, maintain flame stability, and prevent the combustion chamber from going out.

[0055] During normal operation of the combustion chamber, the ignition device 12 is de-energized, the magnetic pole repulsion disappears, and the ignition nozzle 801 moves outward under the action of aerodynamic force, avoiding the ablation problem of the ignition nozzle 801. The high-temperature gas generated in the combustion chamber enters the turbine along the axial direction, driving it to do work. In all stable operating states of the combustion chamber, the pre-combustion stage maintains the equivalence ratio design to maintain flame stability. Although the NOx pollution emission is relatively large, it accounts for a small proportion of the overall emission due to the very low intake ratio. The main combustion stage adopts an ultra-lean design, resulting in extremely low NOx pollution emissions, and its intake ratio is large, which determines the overall emission level of the combustion chamber. In summary, the NOx emissions of this combustion chamber in all states can be further reduced compared to existing lean center stage combustion chambers.

[0056] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A smart pilot flame-out combustion chamber, characterized by, include: The diffuser (1) is connected to the housing (2); The casing (2) is equipped with a flame tube (3), and the flame tube (3) has a reflux zone inside, and the reflux zone is surrounded by a high-speed shear layer. Ignition system (8) includes ignition nozzle (801); in ignition system (8), a permanent magnet (10) is provided at the end of the ignition nozzle (801) away from the flame tube (3), and the permanent magnet (10) drives the ignition nozzle (801) to slide radially along the flame tube (3); an electromagnet (9) is installed on the side of the permanent magnet (10) away from the flame tube (3), and the electromagnet (9) is stationary relative to the flame tube (3); when the electromagnet (9) is energized, the S pole or N pole of the electromagnet (9) and the permanent magnet (10) are arranged facing each other; The ignition nozzle (801) and the electromagnet (9) are both connected to an ignition device (12). The ignition device (12) is used to detect the air pressure inside the casing (2) and control the working state of the ignition nozzle (801) and the electromagnet (9) based on the air pressure. When the flame tube (3) is ignited, or when the pressure inside the casing (2) is lower than the preset value, or when the pressure change rate inside the casing (2) exceeds the preset range, the ignition nozzle (801) moves through the high-speed shear layer to the recirculation zone.

2. The intelligent ignition and shutdown combustion chamber according to claim 1, characterized in that, The diffuser (1) has an inner diameter that gradually increases in the direction toward the casing (2).

3. The intelligent ignition and shutdown combustion chamber according to claim 1, characterized in that, The casing (2) is connected to one end of the flame tube (3).

4. The intelligent ignition and shutdown combustion chamber according to claim 1, characterized in that, The flame tube (3) is provided with a number of pre-combustion inlets (301) and a number of main combustion inlets (302) at one end facing the diffuser (1). The pre-combustion air inlet (301) is located inside the main combustion air inlet (302); Both the pre-combustion air inlet (301) and the main combustion air inlet (302) are located at the inlet of the flame tube (3); The air intake ratio of the pre-combustion air intake (301) to the main combustion air intake (302) is 15:1; The pre-combustion air inlet (301) and the main combustion air inlet (302) are connected by a platform stage (6), the height of which is 5% to 30% of the cavity height of the flame tube (3).

5. The intelligent ignition and shutdown combustion chamber according to claim 4, characterized in that, A pre-combustion stage vortex generator (5) is installed inside the pre-combustion inlet (301), and a main combustion stage vortex generator (4) is installed inside the main combustion inlet (302).

6. The intelligent ignition and shutdown combustion chamber according to claim 5, characterized in that, A fuel nozzle (7) is also installed at one end of the flame tube (3) facing the diffuser (1), and the fuel nozzle (7) is located at the end of the flame tube (3) facing the diffuser (1); The mist cone angle of the fuel nozzle (7) is 0~150°.

7. An ignition method, characterized in that, Combustion chamber for use in any one of claims 1-6 with intelligent ignition shutdown.

8. The ignition method according to claim 7, characterized in that, Includes the following steps: When the combustion chamber is ignited, or when the internal air pressure of the casing (2) is detected to be lower than the preset value, or when the rate of change of the internal air pressure of the casing (2) is detected to exceed the preset range, the electromagnet (9) in the ignition system (8) is energized to generate a magnetic field that repels the permanent magnet (10) in the ignition system (8). When the repulsive force of the magnetic field is greater than the thrust of the compressed air entering the casing (2), it drives the ignition nozzle (801) to move from the high-speed shear layer to the recirculation zone. When the electromagnet (9) is de-energized, the ignition nozzle (801) is moved from the recirculation zone to the high-speed shear layer by the compressed air entering the casing (2).

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