Active control device for combustion oscillations in a gas turbine

Abstract

This invention provides an active control device for combustion oscillation in a gas turbine, belonging to the field of energy and power. It includes an acoustic array loudspeaker, a photoelectric sensor, and a signal processor. The acoustic array loudspeaker is located at the front end of the burner, which includes a combustion nozzle and a combustion flame tube. The combustion nozzle is located at the inlet end of the combustion flame tube. The photoelectric sensor is located outside the combustion flame tube and electrically connected to the signal processor, which is also electrically connected to the acoustic array loudspeaker. This invention, by adding a loudspeaker at the front end of the burner, utilizes sound waves to precisely change the phase difference between sound pressure oscillation and heat release rate fluctuations, achieving active control of combustion oscillation in the gas turbine. It can flexibly address combustion oscillation problems under different operating conditions, exhibiting better adaptability and adjustability.

Description

Technical Field

[0001] This utility model relates to the field of energy and power technology, specifically to an active control device for combustion oscillation in a gas turbine. Background Technology

[0002] As a core power source in aviation, power, and other fields, the stability of the combustion system is crucial for gas turbines. However, combustion oscillations severely impact the performance and lifespan of gas turbines. Combustion oscillations are self-excited oscillations generated by the coupling of the combustion process with the acoustic environment. They can lead to excessively high pressure pulsation amplitudes, resulting in noise, vibration, and other problems that damage the combustion system.

[0003] Existing technologies absorb or reduce combustion oscillation energy by incorporating resonators with specific structures within the combustion chamber, thereby suppressing oscillations. However, these passive control methods often require significant modifications to the hardware structure, such as the combustion chamber. This not only increases the complexity and cost of the equipment but may also affect combustion efficiency. Furthermore, once the modifications are completed, their adaptability and adjustability are poor, making it difficult to address combustion oscillation problems under different operating conditions. Utility Model Content

[0004] The technical problem to be solved by this invention is how to achieve active control of combustion oscillations in a gas turbine.

[0005] To solve the above-mentioned technical problems, the present invention provides the following technical solution: an active control device for combustion oscillation of a gas turbine, comprising an acoustic array loudspeaker, a photoelectric sensor and a signal processor, wherein the acoustic array loudspeaker is located at the front end of the burner, the burner comprises a combustion nozzle and a combustion flame tube, the combustion nozzle is located at the inlet end of the combustion flame tube, the photoelectric sensor is located outside the combustion flame tube and is electrically connected to the signal processor, and the signal processor is electrically connected to the acoustic array loudspeaker.

[0006] This invention adds an array of loudspeakers to the front end of the burner and a photoelectric sensor to the outside of the combustion flame tube. When natural gas and the mixer are ejected from the combustion nozzle and ignited to form a combustion flame, the photoelectric sensor can capture the heat release rate signal at the combustion cross section of the flame and feed it back to the signal processor. After analysis and processing by the signal processor, it can output the reverse wave intensity, changing the phase difference between the sound pressure oscillation and the heat release rate fluctuation from 90° to 270°. Negative feedback is formed in the combustion chamber, reducing the fluctuation of the heat release rate and the pressure oscillation, thereby reducing the downstream oscillation. This achieves active control of the combustion oscillation of the gas turbine, ensuring the operational stability and efficiency of the gas turbine.

[0007] Preferably, the burner further includes a swirler located at the outlet of the combustion nozzle.

[0008] This invention enhances the mixing of fuel and air by placing a swirler at the outlet of the combustion nozzle, thereby improving combustion efficiency. It also stabilizes the position of the flame combustion cross-section and keeps it within the effective monitoring range of the photoelectric sensor.

[0009] Preferably, the combustion nozzle has a cylindrical structure, the combustion flame tube has a frustum-shaped structure, and the diameter of the combustion nozzle is smaller than the diameter of the inlet end of the combustion flame tube.

[0010] The combustion nozzle of this invention has a cylindrical structure, which can provide a uniform straight flow channel. The combustion flame tube has a frustum-shaped structure, and its gradually expanding cross section can naturally match the expansion trend of the rotating airflow generated by the cyclone, thus avoiding the flow separation that occurs in traditional cylindrical tubes.

[0011] Preferably, the combustion nozzle is arranged coaxially with the combustion flame tube.

[0012] This invention arranges the combustion nozzle and the combustion flame tube coaxially, and combined with the swirler, it enables the combustion nozzle to form a smooth, progressive structure with straight-tube acceleration, swirling diffusion, and conical stability after naturally connecting to the inlet of the combustion flame tube.

[0013] Preferably, the inner wall of the combustion flame tube is coated with a high-temperature resistant ceramic coating with a thickness of 0.5mm-2mm.

[0014] This invention coats the inner wall of the combustion flame tube with a high-temperature resistant ceramic coating, which can protect the inner wall of the flame tube, extend its lifespan, and reduce the impact of deformation on the sensor.

[0015] Preferably, the photoelectric sensor is a photoelectric heat release rate sensor and there are several of them, which are evenly arranged circumferentially on the outside of the combustion flame tube.

[0016] This invention can simultaneously detect the heat release rate fluctuations at different angles of the flame combustion surface, providing full-domain data input for the signal processor.

[0017] Preferably, the output end of the photoelectric sensor is connected to the signal processor via a shielded cable, the outer layer of which is covered with a high-temperature resistant insulating material.

[0018] Preferably, the signal output terminal of the signal processor is connected to the sound array speaker via a shielded cable, the outer layer of which is covered with a high-temperature resistant insulating material.

[0019] This invention uses a shielded cable, which can suppress electromagnetic interference and ensure the stability of weak signal transmission. It also uses a high-temperature resistant insulation layer to prevent the cable from aging or breaking in high-temperature environments.

[0020] Preferably, the acoustic array loudspeaker has a ring array structure.

[0021] The ring array structure of the acoustic array loudspeaker can ensure that sound waves propagate evenly in the combustion chamber, avoiding control failure caused by uneven local sound pressure.

[0022] Preferably, it also includes a temperature sensor and a pressure sensor, located at the inlet and outlet of the combustion flame tube, respectively.

[0023] By adding temperature and pressure sensors, the device's fault tolerance can be improved by combining data from photoelectric sensors.

[0024] Compared with existing technologies, the advantages of this utility model are:

[0025] (1) No major modifications are required to the hardware structure such as the combustion chamber, which reduces the complexity and cost of the equipment and avoids the negative impact on combustion efficiency.

[0026] (2) By adding a loudspeaker at the front end of the burner, the phase difference between the sound pressure oscillation and the heat release rate fluctuation can be precisely changed using sound waves. This can flexibly address the combustion oscillation problem under different working conditions and has good adaptability and adjustability.

[0027] (3) By precisely controlling the phase difference of the sound waves, negative feedback is formed in the combustion chamber, reducing the fluctuation of heat release rate and pressure oscillation, thereby improving the operating stability and efficiency of the gas turbine. Attached Figure Description

[0028] Figure 1 This is a structural diagram of the device according to an embodiment of the present utility model. Detailed Implementation

[0029] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. 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 should fall within the protection scope of the present invention.

[0030] Example

[0031] like Figure 1 As shown, this embodiment provides an active device for combustion oscillation in a gas turbine, including an acoustic array loudspeaker 1, a combustion nozzle 2, a swirler 3, a photoelectric sensor 5 (in this embodiment, a photoelectric heat release rate sensor), a signal processor 6, a combustion flame tube 7, and an ignition electrode 8.

[0032] The acoustic array loudspeaker 1 is located at the front end of the burner. In this embodiment, the acoustic array loudspeaker 1 is a ring array structure, which can ensure that the sound waves propagate evenly in the combustion chamber and avoid control failure caused by uneven local sound pressure.

[0033] The combustion nozzle 2 is located at the inlet end of the combustion flame tube 7. The combustion nozzle 2 has a cylindrical structure, with natural gas flowing inside and air flowing outside. The combustion flame tube 7 has a frustum-shaped structure. The cylindrical structure of the combustion nozzle provides a uniform straight flow channel, and the frustum-shaped structure of the combustion flame tube naturally matches the expansion trend of the rotating airflow generated by the cyclone separator, avoiding the flow separation that occurs in traditional cylindrical tubes.

[0034] The combustion nozzle 2 is coaxially arranged with the combustion flame tube 7. The diameter of the combustion nozzle 2 is smaller than the inlet diameter of the combustion flame tube 7. The inner wall of the combustion flame tube 7 is coated with a high-temperature resistant ceramic coating with a thickness of 0.5mm-2mm (1mm in this embodiment), which protects the inner wall of the flame tube. The combustion flame tube 7 is also equipped with cooling holes with a diameter of 1mm. Cooling air is drawn from the compressor and used as cooling air, forming a gas film cooling under a certain pressure to further prevent the flame tube from being ablated. The swirler 3 is located at the outlet of the combustion nozzle 2. By setting the swirler at the outlet of the combustion nozzle, the mixing effect of fuel and air can be enhanced, and the combustion efficiency can be improved. By arranging the combustion nozzle and the combustion flame tube coaxially, and combining them with the swirler, the combustion nozzle can form a smooth and progressive structure of straight-tube acceleration, swirling diffusion, and conical stability after naturally connecting to the inlet of the combustion flame tube.

[0035] There are several photoelectric sensors 5, eight in this embodiment, which are evenly arranged circumferentially on the outside of the combustion flame tube 7. The output end of the photoelectric sensor 5 is connected to the signal processor 6 through a shielded cable. The outer layer of the cable is covered with a high-temperature resistant insulating material. The signal output end of the signal processor 6 is connected to the sound array speaker through a shielded cable. The outer layer of the cable is also covered with a high-temperature resistant insulating material. Using a shielded cable can suppress electromagnetic interference and ensure the stability of weak signal transmission. Using a high-temperature resistant insulating layer can prevent the cable from aging or breaking in a high-temperature environment.

[0036] In particular, this embodiment also installs temperature sensors and pressure sensors at the inlet and outlet of the combustion flame tube 7, respectively. The monitoring data can be combined with the photoelectric sensor data to improve the fault tolerance of the device.

[0037] In a combustion system, the transfer of energy from unstable heat release to the sound field does not necessarily lead to combustion instability. The combustion process becomes unstable only when the phase difference between the sound pressure oscillation and the heat release rate fluctuation is 0° to 90°, and when the periodic heat release process provides energy to the sound field faster than the rate attenuation and diffusion of the sound waves through the boundary conditions of the combustion chamber.

[0038] The working principle of this utility model is as follows: When natural gas and air are mixed and sprayed from the combustion nozzle 2, they are ignited after passing through the cyclone separator 3 to form a combustion flame, forming a combustion front, i.e., the flame front 4. The photoelectric heat release rate sensor 5 captures the heat release rate signal at the cross section of the flame front and feeds it back to the signal processor 6. After the signal processor 6 analyzes and processes the signal, the reverse wave intensity is output through the acoustic array speaker 1, changing the phase difference between the sound pressure oscillation and the heat release rate fluctuation from 90° to 270°. Negative feedback is formed in the combustion chamber, reducing the fluctuation of the heat release rate and the pressure oscillation, thereby reducing the downstream oscillation. This achieves active control of the combustion oscillation of the gas turbine and ensures the operational stability and efficiency of the gas turbine.

[0039] This invention requires no hardware modifications: it eliminates the need for significant alterations to the combustion chamber and other hardware structures, reducing the complexity and cost of the equipment while avoiding negative impacts on combustion efficiency.

[0040] It also has flexible adaptability: by adding a loudspeaker at the front end of the burner, the phase difference between the sound pressure oscillation and the heat release rate fluctuation is precisely changed by using sound waves, which can flexibly deal with the combustion oscillation problem under different working conditions and has better adaptability and adjustability.

[0041] It can improve stability and efficiency: By precisely controlling the phase difference of sound waves, negative feedback is formed in the combustion chamber, reducing fluctuations in heat release rate and pressure oscillations, thereby improving the operational stability and efficiency of the gas turbine. It also solves problems such as insufficient actuator reliability and slow response speed in existing active control technologies, providing a strong guarantee for the high-performance operation of gas turbines.

[0042] The above-disclosed embodiments are merely preferred embodiments of the present utility model and should not be construed as limiting the scope of protection of the present utility model. Therefore, any equivalent changes made in accordance with the claims of the present utility model shall still fall within the scope of the present utility model.

Claims

1. A gas turbine combustion oscillation active control device, characterized in that, It includes an acoustic array loudspeaker, a photoelectric sensor, and a signal processor. The acoustic array loudspeaker is located at the front end of the burner. The burner includes a combustion nozzle and a combustion flame tube. The combustion nozzle is located at the inlet end of the combustion flame tube. The photoelectric sensor is located outside the combustion flame tube and is electrically connected to the signal processor. The signal processor is electrically connected to the acoustic array loudspeaker.

2. The active control device for combustion oscillation in a gas turbine according to claim 1, characterized in that, The burner also includes a swirler located at the outlet of the combustion nozzle.

3. The active control device for combustion oscillation of a gas turbine according to claim 2, characterized in that, The combustion nozzle has a cylindrical structure, and the combustion flame tube has a frustum-shaped structure. The diameter of the combustion nozzle is smaller than the diameter of the inlet end of the combustion flame tube.

4. The active control device for combustion oscillation in a gas turbine according to claim 3, characterized in that, The combustion nozzle is arranged coaxially with the combustion flame tube.

5. The active control device for combustion oscillation of a gas turbine according to claim 4, characterized in that, The inner wall of the combustion flame tube is coated with a high-temperature resistant ceramic coating with a thickness of 0.5mm-2mm.

6. The active control device for combustion oscillation in a gas turbine according to claim 1, characterized in that, The photoelectric sensor is a photoelectric heat release rate sensor, and there are several of them, which are evenly arranged circumferentially on the outside of the combustion flame tube.

7. The active control device for combustion oscillation in a gas turbine according to claim 6, characterized in that, The output of the photoelectric sensor is connected to the signal processor via a shielded cable, the outer layer of which is covered with a high-temperature resistant insulating material.

8. The active control device for combustion oscillation of a gas turbine according to claim 7, characterized in that, The signal output terminal of the signal processor is connected to the sound array speaker via a shielded cable, the outer layer of which is covered with a high-temperature resistant insulating material.

9. The active control device for combustion oscillation in a gas turbine according to claim 8, characterized in that, The sound array loudspeaker has a ring array structure.

10. The active control device for combustion oscillation of a gas turbine according to claim 1, characterized in that, It also includes temperature and pressure sensors, located at the inlet and outlet of the combustion flame tube, respectively.

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