Combustion state monitoring method based on micro gas turbine combustion chamber

Abstract

The invention discloses a combustion state monitoring method based on a micro gas turbine combustion chamber. The method comprises the steps of temperature change and distribution in the combustion chamber, pressure pulsation of combustion gas in the combustion chamber, combustion tail gas component and content measurement, combustion efficiency measurement and combustion flame state monitoring. Specifically, the temperature change and distribution are monitored through the arrangement of thermocouples; data of gas pressure pulsation are collected through a pressure pulsation sensor, and data analysis processing can be conducted on the gas pressure pulsation so that a researcher can analyze the gas pressure pulsation; the flue gas analyzer monitors the components and the content of tail gas generated in the combustion process, and then the combustion efficiency is calculated; the combustion flame state is analyzed through flame pictures shot by a high-speed flame camera. The four monitoring modes are carried out at the same time, data are transmitted to a computer to be analyzed, and reference can be provided for subsequent further analysis of combustion performance, power generation performance, operation maintenance and fault diagnosis of the gas turbine.

Description

Technical Field

[0001] The present invention relates to the field of micro gas turbine combustion test monitoring technology and performance evaluation, and specifically to a method for monitoring and evaluating temperature, pressure pulsation, tail gas composition, combustion efficiency and flame state generated during combustion of a commercial micro gas turbine. Background Art

[0002] Micro gas turbine is a new type of small thermal generator, with a power of 25-300kW, and has the advantages of good fuel adaptability, high reliability, environmental friendliness, and easy use. With the continuous pursuit of green energy and sustainable development in countries around the world, micro gas turbine will become the mainstream of energy generation technology in the future. However, my country started late in the research of micro gas turbines, and there are still considerable challenges in some aspects. The main problems are as follows:

[0003] 1. The temperature in the combustion chamber can characterize the combustion state, and the uniformity of temperature distribution and temperature extremes will affect the structural strength of the combustion chamber. However, the combustion chamber of a micro gas turbine is usually in a closed state, making it difficult to measure its internal temperature. At the same time, there is little real-time analysis of temperature distribution.

[0004] 2. During operation, the flame pressure pulsation inside the combustion chamber is an important state parameter, which is affected by many factors such as the fuel and air mixing ratio, flow rate, ambient humidity, temperature, etc. Too violent and irregular pressure pulsation will cause incomplete combustion, thus causing environmental pollution and even serious consequences such as device explosion. In addition, since the use of sensors is limited by the high temperature of gas, it is difficult to directly extract the pressure pulsation signal;

[0005] 3. The evaluation of the stability performance of gas turbine combustion tests is a complex and diverse process. Generally speaking, the flame cannot be directly observed during the combustion of a micro gas turbine, and it is difficult to directly obtain information such as the flame pulsation signal and exhaust gas composition. In addition, there are few multi-dimensional and systematic evaluations of the combustion state of the combustion chamber. Summary of the invention

[0006] In view of the above problems, the purpose of the present invention is to provide a combustion state monitoring method based on a micro gas turbine combustion chamber. First, the combustion chamber of a commercial gas turbine is fixed on a device frame, the fuel and compressed air intake pipes are designed, a micro gas turbine combustion chamber test platform is built, and monitoring devices such as thermocouples, pressure pulsation sensors, flue gas analyzers, and high-speed flame cameras are installed respectively. According to a customized monitoring method, the temperature uniformity, gas pressure pulsation, combustion efficiency, combustion stability, etc. inside the combustion chamber are characterized.

[0007] To achieve the above purpose, the technical solution adopted by the present invention is as follows:

[0008] A method for monitoring the combustion state of a micro gas turbine combustion chamber, the method comprising the following steps:

[0009] S1. Simplify the combustion chamber model according to the research content, design the fuel and compressed air intake pipes, and build a micro gas turbine combustion chamber test platform;

[0010] S2. Install the thermocouple, pressure pulsation sensor, flue gas analyzer and high-speed flame camera at appropriate locations on the test platform;

[0011] S3, custom measurement data extraction method, custom combustion state judgment formula and combustion efficiency judgment formula;

[0012] S4. Record, collect and organize the monitored combustion test data, and subsequently optimize the various indicators of the micro gas turbine combustion chamber according to actual needs.

[0013] Furthermore, in the step S1, the combustion chamber part of the micro gas turbine is retained, and the remaining parts, including the turbine system and the power generation system, are removed, and an air cavity flange is installed at the combustion chamber port to ensure that the compressed air completely enters the combustion chamber.

[0014] Furthermore, 26 holes are opened in the circumference of the air cavity flange for installing fixed air intake cavities and thermocouples of different lengths to realize temperature monitoring of different axial depths, radial distances, and circumferential angles inside the combustion chamber, thereby realizing the measurement of temperature distribution in the combustion chamber.

[0015] Furthermore, for a certain measurement point, its time domain data is analyzed to determine the operating state of the combustion:

[0016] Specifically, the axial depth setting thermocouple movement distance range is 0~L, and each movement length is L i , then n*L i =L, n is the number of times the measurement movement is required to achieve measurement at different axial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain axial direction;

[0017] The temperature gradient distribution in the axial direction is plotted at the position L i --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber;

[0018] Similarly, the radial distance setting thermocouple movement distance range is 0~R, and each movement length is R j , then m*R j =R, m is the number of times to be measured and moved, to achieve measurement at different radial positions, so as to obtain the temperature distribution gradient in the combustion chamber along a certain radial direction.

[0019] The temperature gradient distribution in the radial direction is plotted at position R j --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber;

[0020] Similarly, within the range of 0 to 360° in the circumferential direction of the annular combustion chamber, it is evenly subdivided into 26 measuring points to achieve temperature measurement at different circumferential positions, thereby obtaining the temperature distribution along a certain circumferential direction in the combustion chamber and the temperature uniformity of the cross section;

[0021] The temperature distribution in a certain circumferential direction is plotted at an angle θ k --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber;

[0022] Monitor the temperature uniformity in a certain axial direction and different radial positions:

[0023]

[0024] Among them, Δ TK is the temperature uniformity, T k is the temperature measurement value of the measuring point, ℃, is the arithmetic mean of K measured values, ℃; K is the number of measurements.

[0025] Furthermore, by combining the time domain data of temperature, the temperature gradient change at a specific measuring point is monitored to determine the combustion state of the combustion chamber.

[0026]

[0027] in, is the temperature change rate, Δt is the combustion state determination monitoring time, which is generally less than 1s, ΔT is the temperature change during the monitoring time, and a and b are the specific values ​​for state determination, which are set according to actual conditions.

[0028] Furthermore, the pressure pulsation sensor is placed at the exhaust outlet of the combustion chamber to measure the airflow pressure pulsation signal at the outlet of the combustion chamber. The collected time domain signal can be analyzed and processed by time-frequency analysis method, including fast Fourier transform, to indicate whether an abnormal combustion state occurs in the combustion chamber, and to perform early warning and processing:

[0029] The expression of fast Fourier transform is an efficient calculation method of discrete Fourier transform, and its basic formula is as follows:

[0030]

[0031] Where X[u] is the u-th frequency component of the frequency domain signal, x[w] is the w-th sampling point of the time domain signal, W is the total number of samples of the signal, and h is the imaginary unit;

[0032] If abnormal oscillating combustion occurs, analyze its characteristic frequency f λ , we have the following experience judgment:

[0033]

[0034] Furthermore, the flue gas analyzer is located at the exhaust gas outlet of the combustion chamber to monitor the generation of CO, CO2, UHC, NO x Content, further, its combustion efficiency can be calculated as follows:

[0035]

[0036] Where η is the combustion efficiency; Q CO , Q UHC , Q H2 , Q NO is the lower calorific value of the corresponding product, MJ / Nm 3 ; [CO], [UHC], [H2], [NO] are the volume concentrations in the exhaust gas, ppm; V g is the flue gas volume flow rate, m 3 / h; V f is the gas volume flow rate, m 3 / h;Q LHV is the lower calorific value of the gas, MJ / Nm 3 .

[0037] Furthermore, the high-speed flame camera is placed directly in front of the combustion chamber, and records high-definition flame images of the diffusion combustion and premixed combustion states in the combustion chamber through frame sampling. By selecting a large number of particles to analyze the flame shape, flame front structure and flame brightness, the flame movement state is obtained, and then the combustion condition is analyzed.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] 1. The present invention simplifies the complex turbine system and power generation system in the combustion chamber of the micro gas turbine, and adds an air cavity flange to ensure the sealing requirements when compressed air enters. At the same time, 26 holes are opened in the circumference of the air cavity flange to install a fixed air intake cavity and also to install a thermocouple. The axial, radial distance and circumferential angle of each thermocouple measuring point can be adjusted to meet the diversified and multi-dimensional temperature monitoring inside the combustion chamber.

[0040] 2. The present invention transforms the structure of the combustion chamber, opens a combustion exhaust gas outlet at the end, and constructs an open combustion chamber test system, which is convenient for monitoring pressure pulsation, monitoring the content and composition of combustion exhaust gas, measuring combustion efficiency, and monitoring flame combustion state;

[0041] 3. The custom collection, processing and analysis model proposed in the present invention has good characterization capabilities through custom temperature uniformity formula, time domain-frequency domain signal conversion formula, combustion efficiency calculation formula and flame particle instantaneous velocity formula, which have been verified by experiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 The combustion chamber combustion state monitoring overall device of the present invention;

[0043] Figure 2 It is a schematic diagram of temperature monitoring for combustion state monitoring of the combustion chamber of the present invention;

[0044] Figure 3 This is a schematic diagram of monitoring gas content components for monitoring the combustion state of the combustion chamber of the present invention;

[0045] Figure 4 It is a schematic diagram of the pressure pulsation monitoring of the combustion state monitoring of the combustion chamber of the present invention;

[0046] Figure 5 This is a schematic diagram of flame state monitoring for combustion chamber combustion state monitoring of the present invention;

[0047] Figure 6 It is a schematic diagram of the overall process of combustion chamber combustion state monitoring of the present invention. DETAILED DESCRIPTION

[0048] The following will provide a clear and complete description of the technical solutions in the embodiments of the present invention in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments, and the directional words such as up, down, left, and right described in the text are limited to the positional relationship of the devices in the drawings of the present embodiment. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0049] The following is a detailed description of a combustion state monitoring method and device based on a micro gas turbine combustion chamber according to the present invention in conjunction with the accompanying drawings.

[0050] See attached Figure 1 and Figure 2 , a combustion state monitoring device based on a micro gas turbine combustion chamber provided by the present invention is given, which mainly includes four monitoring modules: temperature monitoring module, pressure pulsation monitoring module, gas content component monitoring module, and combustion flame image acquisition module. In addition, the combustion chamber performance monitoring device mainly includes: 1-combustion chamber support frame, 2-air cavity flange, 3-(fuel inlet) flame nozzle, 4-compressed air inlet, 5-igniter, 6-combustion chamber shell, 7-exhaust exhaust outlet, 8-flue gas analyzer sampler, 9-pressure pulsation sensor, 10-high-speed flame camera, 11-thermocouple.

[0051] See attached Figure 2 The temperature monitoring module of the present invention is provided. The thermocouples are installed on the flange of the air cavity and are evenly distributed in the circumferential direction. The thermocouples can be arranged in the axial direction L i and radial R i Move freely to better monitor the temperature change, distribution, uniformity, etc. inside the combustion chamber;

[0052] See attached Figure 3 , the exhaust gas content component monitoring module of the present invention is provided, which is monitored by a flue gas analyzer, and is placed at the exhaust gas discharge outlet to monitor the various exhaust gas contents, components, combustion efficiency, etc. generated during the combustion process;

[0053] See attached Figure 4 , a pressure pulsation monitoring module of the present invention is provided, which is monitored by a pressure pulsation sensor, which is placed at the side of the exhaust gas outlet and after the flue gas analyzer to monitor the pressure pulsation of the combustion gas generated by the combustion inside the combustion chamber;

[0054] See attached Figure 5 , a combustion flame image acquisition module of the present invention is provided, which is acquired by a high-speed flame camera, which is placed at a position far away from the exhaust gas outlet to capture image information of the flame when it is burning;

[0055] In addition, more importantly, the present invention provides a combustion state monitoring method based on a micro gas turbine combustion chamber, referring to Figure 6 As shown, it includes the following steps:

[0056] S1. Simplify the combustion chamber model according to the research content, design the fuel and compressed air intake pipes, and build a gas turbine combustion chamber test platform;

[0057] The combustion chamber part of the micro gas turbine is retained, the remaining part is removed, and an air cavity flange is added at the combustion chamber port to ensure that the compressed air completely enters the combustion chamber;

[0058] S2. Install the thermocouple, pressure pulsation sensor, flue gas analyzer and high-speed flame camera at appropriate locations on the test platform;

[0059] S3, custom measurement data extraction method (temperature monitoring, gas content monitoring, pressure pulsation monitoring, high-speed flame camera), custom combustion state (pressure pulsation monitoring) judgment formula and combustion efficiency (gas content monitoring) evaluation formula;

[0060] S4. Record, collect and organize the monitored combustion test data, and subsequently optimize the various indicators of the micro gas turbine combustion chamber according to actual needs;

[0061] Specifically, 26 holes are opened around the flange of the air cavity to install fixed air intake cavities and thermocouples of different lengths to monitor the temperature of different axial depths, radial distances, and circumferential angles inside the combustion chamber, thereby measuring the temperature distribution inside the combustion chamber. In addition, for a certain measurement point, its time domain data can be analyzed to determine the operating status of the combustion chamber.

[0062] Specifically, the axial depth setting thermocouple movement distance range is 0~L, and each movement length is L i , then n*L i =L (n is the number of movement required for measurement, which is user-defined), which can realize the measurement of different axial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain axial direction;

[0063] The temperature gradient distribution in the axial direction can be plotted at the position L i --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0064] Similarly, the radial distance setting thermocouple movement distance range is 0~R, and each movement length is R j , then m*R j =R (m is the number of movement required for measurement, which is user-defined), which can realize the measurement of different radial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain radial direction.

[0065] The temperature gradient distribution in the radial direction can be plotted at the position R i --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0066] Similarly, within the range of 0 to 360° in the circumferential direction of the annular combustion chamber, it can be evenly subdivided into 26 measuring points, and temperature measurements at different circumferential positions can be realized, thereby obtaining the temperature distribution in the combustion chamber along a certain circumferential direction and the temperature uniformity of the cross section.

[0067] The temperature distribution in a certain circumferential direction can be plotted as “angle θ k --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0068] Monitor the temperature uniformity in a certain axial direction and different radial positions:

[0069]

[0070] Among them, Δ TK is the temperature uniformity, T k is the temperature measurement value of the measuring point, ℃, is the arithmetic mean of K measured values, ℃; K is the number of measurements.

[0071] In addition, combined with the time domain data of temperature, the temperature gradient change at a specific measuring point is monitored to determine the combustion state of the combustion chamber.

[0072]

[0073] in, is the temperature change rate, Δt is the combustion state determination monitoring time, which should generally be less than 1s (greater than 3 times the thermocouple response time), ΔT is the temperature change during the monitoring time, and a and b are the specific values ​​for state determination, which can be set according to actual conditions.

[0074] The pressure pulsation sensor is placed at the exhaust outlet of the combustion chamber to measure the airflow pressure pulsation signal at the outlet of the combustion chamber. The collected time domain signal can be analyzed and processed by time-frequency analysis method, such as fast Fourier transform (FFT), to indicate whether abnormal combustion state occurs in the combustion chamber, and to carry out early warning and processing.

[0075] The expression of Fast Fourier Transform (FFT) is an efficient calculation method of Discrete Fourier Transform (DFT). Its basic formula is as follows:

[0076]

[0077] Where X[u] is the u-th frequency component of the frequency domain signal, x[w] is the w-th sampling point of the time domain signal, W is the total number of samples of the signal, and h is the imaginary unit;

[0078] If abnormal oscillating combustion occurs, its characteristic frequency f can be analyzed λ , we have the following experience judgment:

[0079]

[0080] The flue gas analyzer is located at the exhaust gas outlet of the combustion chamber to monitor the generation of CO, CO2, UHC, NO x Content, further, its combustion efficiency can be calculated as follows:

[0081]

[0082] Where η is the combustion efficiency; Q CO , Q UHC , Q H2 , Q NO is the lower calorific value of the corresponding product, MJ / Nm 3 ; [CO], [UHC], [H2], [NO] are the volume concentrations in the exhaust gas, ppm; V g is the flue gas volume flow rate, m 3 / h; V fis the gas volume flow rate, m 3 / h;Q LHV is the lower calorific value of the gas, MJ / Nm 3 ;

[0083] The model and function of the high-speed flame camera can be replaced according to different monitoring requirements. For example, this experiment focuses on monitoring the flame shape, flame front structure and flame brightness during the combustion process in the combustion chamber. The flame camera is used in conjunction with particle image velocimetry (PIV), hydroxyl planar laser induced fluorescence (OH-PLIF) and other technologies to take the required flame photos for researchers to post-process and analyze.

[0084] According to the above-mentioned method for monitoring the combustion state of a micro gas turbine combustion chamber, the analysis contents of each module specifically include:

[0085] Thermocouples mainly monitor the uniformity, temperature change and distribution of heat generated inside the combustion chamber. They can monitor the temperature gradients in the axial, radial and circumferential directions inside the combustion chamber, and judge the combustion conditions and long-term operation status inside the combustion chamber by the temperature distribution status.

[0086] The pressure pulsation sensor monitors the gas pulsation degree caused by internal combustion, and converts the complex time domain signal into frequency domain and complex frequency domain signals with obvious characteristics through fast Fourier transform, Laplace transform, Z transform, etc., so as to judge the stability of the internal system;

[0087] The flue gas analyzer monitors the exhaust emission content in the combustion chamber. The fuel used in this test is propane (C3H8), which reacts with air to produce CO, CO2, UHC, NO x etc., calculate the combustion efficiency by monitoring the flow rate and content of each component of the exhaust gas;

[0088] The high-speed flame camera records high-definition flame images of the diffusion combustion and premixed combustion states in the combustion chamber through frame sampling. By selecting a large number of particles to analyze the flame shape, flame front structure and flame brightness, the flame movement state can be obtained and the combustion condition can be analyzed.

[0089] Specifically, a specific implementation scheme of a combustion state monitoring method based on a micro gas turbine combustion chamber is as follows:

[0090] S1. Temperature monitoring inside the combustion chamber:

[0091] The inner surface of the combustion chamber is an inner shell that is approximately cylindrical in shape. The monitoring method provided by the present invention is: 26 holes are opened in the circumference of the outer ring of the air chamber flange, which are used to install the fixed air intake chamber and the thermocouple, and the length of the thermocouple can be adjusted to realize the temperature monitoring of different axial depths, radial distances, and circumferential angles inside the combustion chamber, thereby realizing the measurement of the temperature distribution inside the combustion chamber. In addition, for a certain measurement point, its time domain data can be analyzed to determine the operating state of the combustion chamber.

[0092] Specifically, the axial depth setting thermocouple movement distance range is 0~L, and each movement length is L i , then n*L i =L (n is the number of movement required for measurement, which is user-defined), which can realize the measurement of different axial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain axial direction;

[0093] The temperature gradient distribution in the axial direction can be plotted at the position L i --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0094] Similarly, the radial distance setting thermocouple movement distance range is 0~R, and each movement length is R j , then m*R j =R (m is the number of movement required for measurement, which is user-defined), which can realize the measurement of different radial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain radial direction.

[0095] The temperature gradient distribution in the radial direction can be plotted at the position R i --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0096] Similarly, within the range of 0 to 360° in the circumferential direction of the annular combustion chamber, it can be evenly subdivided into 26 measuring points, and temperature measurements at different circumferential positions can be realized, thereby obtaining the temperature distribution in the combustion chamber along a certain circumferential direction and the temperature uniformity of the cross section.

[0097] The temperature distribution in a certain circumferential direction can be plotted as “angle θ k --temperature T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber.

[0098] Monitor the temperature uniformity in a certain axial direction and different radial positions:

[0099]

[0100] Among them, Δ TK is the temperature uniformity, T k is the temperature measurement value of the measuring point, ℃, is the arithmetic mean of K measured values, ℃; K is the number of measurements.

[0101] In addition, combined with the time domain data of temperature, the temperature gradient change at a specific measuring point is monitored to determine the combustion state of the combustion chamber.

[0102]

[0103] in, is the temperature change rate, Δt is the combustion state determination monitoring time, which should generally be less than 1s (greater than 3 times the thermocouple response time), ΔT is the temperature change during the monitoring time, and a and b are the specific values ​​for state determination, which can be set according to actual conditions.

[0104] S2. Combustion chamber pressure pulsation monitoring

[0105] The pressure pulsation sensor is placed at the exhaust outlet of the combustion chamber to measure the airflow pressure pulsation signal at the outlet of the combustion chamber. The collected time domain signal can be analyzed and processed by time-frequency analysis method, such as fast Fourier transform (FFT), to indicate whether abnormal combustion state occurs in the combustion chamber, and to carry out early warning and processing.

[0106] The expression of Fast Fourier Transform (FFT) is an efficient calculation method of Discrete Fourier Transform (DFT). Its basic formula is as follows:

[0107]

[0108] Where X[u] is the u-th frequency component of the frequency domain signal, x[w] is the w-th sampling point of the time domain signal, W is the total number of samples of the signal, and h is the imaginary unit;

[0109] If abnormal oscillating combustion occurs, its characteristic frequency f can be analyzed λ , we have the following experience judgment:

[0110]

[0111] S3. Exhaust gas composition monitoring

[0112] The flue gas analyzer is located at the exhaust gas outlet of the combustion chamber to monitor the generation of CO, CO2, UHC, NO x Content, further, its combustion efficiency can be calculated as follows:

[0113]

[0114] Where η is the combustion efficiency; Q CO , Q UHC , Q H2 , Q NOis the lower calorific value of the corresponding product, MJ / Nm 3 ; [CO], [UHC], [H2], [NO] are the volume concentrations in the exhaust gas, ppm; V g is the flue gas volume flow rate, m 3 / h; V f is the gas volume flow rate, m 3 / h;Q LHV is the lower calorific value of the gas, MJ / Nm 3 ;

[0115] S4. Combustion flame status monitoring

[0116] This experiment focuses on monitoring the flame shape, flame front structure and flame brightness during the combustion process in the combustion chamber. The flame camera described in claim 6 is used in conjunction with particle image velocimetry (PIV), hydroxyl planar laser induced fluorescence (OH-PLIF) and other technologies to take the required flame photos for researchers to post-process and analyze.

[0117] The working principle of the present invention is as follows: for commercial micro gas turbine combustion tests, exclusive measuring instruments and measuring methods are customized, and the measurement and characterization of temperature uniformity, temperature change, gas pressure pulsation, combustion exhaust composition, combustion efficiency, flame combustion stability, etc. inside the combustion chamber are explained in detail, which is of great significance for analyzing the characterization of various physical parameters inside the combustion chamber.

[0118] The contents not described in detail in this specification belong to the prior art of professionals in this field.

[0119] The embodiments and principles described above have provided a detailed description of the technical solutions of the present invention. For those skilled in the art, they can still modify the technical solutions recorded in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for monitoring the combustion state of a micro gas turbine combustion chamber, characterized in that: The method comprises the following steps: S1. Simplify the combustion chamber model according to the research content, design the fuel and compressed air intake pipes, and build a micro gas turbine combustion chamber test platform; S2. Install the thermocouple, pressure pulsation sensor, flue gas analyzer and high-speed flame camera at appropriate locations on the test platform; S3, custom measurement data extraction method, custom combustion state judgment formula and combustion efficiency judgment formula; S4. Record, collect and organize the monitored combustion test data, and subsequently optimize the various indicators of the micro gas turbine combustion chamber according to actual needs.

2. A method for monitoring combustion state of a micro gas turbine combustion chamber according to claim 1, characterized in that: In the step S1, the combustion chamber part of the micro gas turbine is retained, and the remaining parts, including the turbine system and the power generation system, are removed, and an air cavity flange is installed at the combustion chamber port to ensure that the compressed air completely enters the combustion chamber.

3. A method for monitoring combustion state of a micro gas turbine combustion chamber according to claim 2, characterized in that: 26 holes are opened around the air cavity flange for installing fixed air intake cavities and thermocouples of different lengths to monitor the temperature at different axial depths, radial distances and circumferential angles inside the combustion chamber, thereby measuring the temperature distribution in the combustion chamber.

4. A method for monitoring combustion state of a micro gas turbine combustion chamber according to claim 3, characterized in that: For a certain measurement point, analyze its time domain data to determine the operating status of the combustion: Specifically, the axial depth setting thermocouple movement distance range is 0~L, and each movement length is L i , then n*L i =L, n is the number of times the measurement movement is required to achieve measurement at different axial positions, thereby obtaining the temperature distribution gradient in the combustion chamber along a certain axial direction; Temperature gradient distribution in the axial direction, plotting the "position L i --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber; Similarly, the radial distance setting thermocouple movement distance range is 0~R, and each movement length is R j , then m*R j =R, m is the number of times to be measured and moved, to achieve measurement at different radial positions, so as to obtain the temperature distribution gradient in the combustion chamber along a certain radial direction. The temperature gradient distribution in the radial direction is plotted at position R j --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber; Similarly, within the range of 0 to 360° in the circumferential direction of the annular combustion chamber, it is evenly subdivided into 26 measuring points to achieve temperature measurement at different circumferential positions, thereby obtaining the temperature distribution along a certain circumferential direction in the combustion chamber and the temperature uniformity of the cross section; The temperature distribution in a certain circumferential direction is plotted at an angle θ k --T” relationship curve, and then analyze the temperature distribution and optimization design of the combustion chamber; Monitor the temperature uniformity in a certain axial direction and different radial positions: Among them, Δ TK is the temperature uniformity, T k is the temperature measurement value of the measuring point, ℃, is the arithmetic mean of K measured values, ℃; K is the number of measurements.

5. A method for monitoring combustion state of a micro gas turbine combustion chamber according to claim 4, characterized in that: Combined with the time domain data of temperature, the temperature gradient change of a specific measuring point is monitored to determine the combustion state of the combustion chamber. in, is the temperature change rate, Δt is the combustion state determination monitoring time, which is generally less than 1s, ΔT is the temperature change during the monitoring time, and a and b are the specific values ​​for state determination, which are set according to actual conditions.

6. The method for monitoring the combustion state of a micro gas turbine combustion chamber according to claim 1, characterized in that: The pressure pulsation sensor is placed at the exhaust outlet of the combustion chamber to measure the airflow pressure pulsation signal at the outlet of the combustion chamber. The collected time domain signal can be analyzed and processed by time-frequency analysis method, including fast Fourier transform, to indicate whether an abnormal combustion state occurs in the combustion chamber, and to perform early warning and processing: The expression of fast Fourier transform is an efficient calculation method of discrete Fourier transform, and its basic formula is as follows: Where X[u] is the u-th frequency component of the frequency domain signal, x[w] is the w-th sampling point of the time domain signal, W is the total number of samples of the signal, and h is the imaginary unit; If abnormal oscillating combustion occurs, analyze its characteristic frequency f λ , we have the following experience judgment:

7. The method for monitoring the combustion state of a micro gas turbine combustion chamber according to claim 1, characterized in that: The flue gas analyzer is located at the exhaust outlet of the combustion chamber to monitor the production of CO, CO2, UHC, and NO in the combustion exhaust. x Content, further, its combustion efficiency can be calculated as follows: Where η is the combustion efficiency; Q CO , Q UHC , Q H2 , Q NO is the lower calorific value of the corresponding product, MJ / Nm 3 ; [CO], [UHC], [H2], [NO] are the volume concentrations in the exhaust gas, ppm; V g is the flue gas volume flow rate, m 3 / h; V f is the gas volume flow rate, m 3 / h;Q LHV is the lower calorific value of the gas, MJ / Nm 3 .

8. The method for monitoring the combustion state of a micro gas turbine combustion chamber according to claim 1, characterized in that: The high-speed flame camera is placed in front of the combustion chamber, and records high-definition flame images of the diffusion combustion and premixed combustion states in the combustion chamber through frame sampling. By selecting a large number of particles to analyze the flame shape, flame front structure and flame brightness, the flame movement state is obtained, and then the combustion condition is analyzed.

Images