Fuel gas analysis system suitable for hydrogen combustion chamber and performance analysis method

Abstract

The invention relates to the technical field of fuel gas continuous sampling analysis experiments, and discloses a fuel gas analysis system suitable for a hydrogen combustion chamber and a performance analysis method.The fuel gas analysis system comprises a sampling rake, a first sample gas pipe, a function conversion valve, a third sample gas pipe, a fuel gas analyzer, a pressure guiding pipe and a pressure transmitter; the sampling rake is arranged at the downstream of an exhaust pipe of the combustion chamber and is communicated with the gas inlet end of the function conversion valve through a first sample gas pipe; one path of the exhaust end of the function conversion valve is communicated with the inlet end of the fuel gas analyzer through a third sample gas pipe and is used for analyzing and measuring the concentration of fuel gas components; and the other path of the exhaust end of the function conversion valve is communicated with the inlet end of the pressure transmitter through the pressure guide pipe and is used for measuring the outlet pressure of the combustion chamber. The invention aims to provide the fuel gas analysis system and the performance analysis method suitable for the hydrogen combustion chamber so as to solve the technical problems that the proportion of water vapor in fuel gas of an existing hydrogen combustion chamber is high, performance parameters are difficult to measure and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of gas continuous sampling and analysis experiments, and particularly relates to a gas analysis system and a performance analysis method suitable for a hydrogen combustion chamber. Background Art

[0002] With the accelerating transformation of the global energy structure towards low-carbonization, hydrogen energy has become the core direction for the clean development of gas turbines due to its zero-carbon characteristics and high calorific value advantages. Hydrogen fuel can not only achieve zero carbon emissions throughout its life cycle through renewable energy electrolysis of water, but its mass calorific value of up to 120 MJ / kg is 2.8 times that of traditional fuels, making it particularly suitable for improving the performance of high-power gas turbines, thus driving the hydrogen combustion chamber to become a key technological breakthrough point for the new generation of gas turbines.

[0003] As the core component of a hydrogen gas turbine, the combustion chamber mainly converts the chemical energy of hydrogen into heat energy. During the design and development process of the combustion chamber, multiple iterations and experimental verifications are required, especially in the experimental verification stage, accurate acquisition of combustion chamber performance parameters is needed. However, the high reactivity of hydrogen fuel leads to a 6-8 times increase in the combustion speed compared to traditional fuels, causing the outlet temperature of the combustion chamber to exceed 2000K, which poses great challenges to the measurement of combustion efficiency, exhaust temperature, pressure, and pollutants such as NOx. Currently, water-cooled or air-cooled temperature rakes are mostly used to measure the outlet temperature, water-cooled or air-cooled pressure rakes are used to measure the outlet pressure, and water-cooled sampling rakes are used to measure the gas components. However, the water-cooled or air-cooled thermocouples will directly affect the measurement accuracy of the outlet temperature, and the temperature rakes, pressure rakes, and sampling rakes with cooling structures are relatively large in size, and there is also interference between multiple rakes, resulting in disorder of the flow field and temperature field in the hydrogen combustion chamber, affecting the combustion performance of the hydrogen combustion chamber, and also affecting the measurement accuracy of the outlet performance parameters of the hydrogen combustion chamber. In addition, existing gas analyzers and post-processing methods have all been developed for aviation kerosene combustion chambers. The gas components after aviation kerosene combustion are mainly gas components, which are completely different from the gas components of the hydrogen combustion chamber, resulting in the complete inapplicability of existing gas analyzers and post-processing methods. Summary of the Invention

[0004] In order to overcome the above-mentioned disadvantages of the prior art, this patent provides a gas analysis system and a performance analysis method suitable for a hydrogen combustion chamber, which solve the problems of high water vapor content in the gas, difficult measurement of gas pressure and component concentration, and from the perspective of chemical reactions, a single sampling rake can solve the technical problems such as difficult accurate measurement of high temperature during the measurement of hydrogen combustion chamber performance parameters, and serious impact on combustion performance due to a large number of sensors and large size. To achieve the above object, the present invention provides the following technical solutions.

[0005] A gas analysis system applicable to a hydrogen combustion chamber, comprising a sampling rake, a first sample gas pipe, a function conversion valve, a third sample gas pipe, a gas analyzer, a pressure guiding pipe, and a pressure transmitter; the sampling rake is arranged downstream of the exhaust pipe of the combustion chamber, and the sampling rake is connected to the intake end of the function conversion valve through the first sample gas pipe; one path of the exhaust end of the function conversion valve is connected to the inlet end of the gas analyzer through the third sample gas pipe, for realizing the analysis and measurement of the gas component concentration; the other path of the exhaust end of the function conversion valve is connected to the inlet end of the pressure transmitter through the pressure guiding pipe, for realizing the measurement of the pressure at the outlet of the combustion chamber.

[0006] As a further improvement of the present invention, it further comprises a water remover, a dryer, and a second sample gas pipe; the water remover, the dryer, and the second sample gas pipe are sequentially arranged between the first sample gas pipe and the intake end of the function conversion valve, and the water remover is connected to the first sample gas pipe.

[0007] As a further improvement of the present invention, it further comprises a first thermocouple and a control unit; the first thermocouple is arranged at the sample gas outlet position of the sampling rake; a water cooling structure is arranged in the sampling rake, and the water cooling structure is connected to an external cooling system, and the water cooling structure is used to cool the sampling rake and the sample gas inside it; the control unit is electrically connected to the first thermocouple and the external cooling system respectively.

[0008] As a further improvement of the present invention, it further comprises a second thermocouple; the second thermocouple is arranged in the first sample gas pipe, and the first sample gas pipe adopts an electrically heated tracing pipe; the control unit is electrically connected to the second thermocouple, for guiding the electrically heated tracing pipe to keep the first sample gas pipe warm.

[0009] As a further improvement of the present invention, it further comprises a third thermocouple and a fourth thermocouple; the third thermocouple is arranged in the second sample gas pipe, and the fourth thermocouple is arranged in the third sample gas pipe; both the second sample gas pipe and the third sample gas pipe adopt electrically heated tracing pipes; the control unit is electrically connected to the third thermocouple and the fourth thermocouple respectively, for guiding the electrically heated tracing pipes to keep the sample gas in the second sample gas pipe and the third sample gas pipe warm.

[0010] As a further improvement of the present invention, it further comprises a first signal line, a second signal line, and a data post-processing unit; one end of the first signal line is electrically connected to the pressure transmitter, and the other end of the first signal line is electrically connected to the data post-processing unit; one end of the second signal line is electrically connected to the gas analyzer, and the other end of the second signal line is electrically connected to the data post-processing unit.

[0011] As a further improvement of the present invention, the sampling rake adopts a multi-point mixing type sampling rake, with a plurality of sampling points evenly arranged on the sampling rake, and the interval between the sampling points is 8 - 12 mm.

[0012] As a further improvement of the present invention, the pressure guiding pipe adopts a stainless steel pipe or a copper pipe.

[0013] On the other hand, the present invention provides a performance analysis method applicable to a hydrogen combustion chamber, comprising the following steps: sampling from the exhaust pipe of the combustion chamber; Keeping the collected fuel gas under pressure and cooling it, removing water and drying it, then measuring the total pressure at the outlet of the combustion chamber with the aid of a pressure transmitter, and measuring the mole fraction of key products with the aid of a fuel gas analyzer; Based on the total pressure at the outlet of the combustion chamber and the measured total pressure at the inlet of the combustion chamber, obtaining the pressure loss coefficient; Measuring the component data of the oxidant (air) of the combustion chamber, and combining with the mole fraction of the products measured by the fuel gas analyzer to solve the pollutant emission indices of NO and NOx and the emission index of H2; Combining the emission indices of H2 and NO and the lower calorific value of H2, calculating to obtain the combustion efficiency; Based on the obtained combustion efficiency, the lower calorific value of H2, and the number of moles of reactants and products, calculating to obtain the fuel gas temperature.

[0014] As a further improvement of the present invention, the step of measuring the component data of the oxidant (air) of the combustion chamber, combining with the data measured by the fuel gas analyzer to solve the pollutant emission indices of NO and NOx and the emission index of H2, calculating to obtain the combustion efficiency and the fuel gas temperature, comprises the following steps: measuring the volume fraction of key components of the oxidant (air) of the combustion chamber; obtaining the mole fractions of O2, CO2, NO, and NOx in the sample gas based on the fuel gas analyzer; establishing a system of equations based on the chemical equilibrium equation to solve the elemental moles of reactants and products; calculating the fuel air ratio of the fuel gas analysis and comparing it with the physically measured fuel air ratio. If the deviation between the calculated fuel air ratio and the physically measured fuel air ratio exceeds the threshold value, then readjust the sampling point position and perform anomaly detection, obtain the mole fractions of O2, CO2, NO, and NOx in the sample gas after adjusting the sampling point based on the fuel gas analyzer, and perform the foregoing steps in sequence, cycling until the fuel air ratio deviation is less than or equal to the threshold value; the threshold value is 5%.

[0015] The present invention has the following beneficial effects: A gas analysis system applicable to a hydrogen combustion chamber includes a sampling rake, a function conversion valve, a gas analyzer, and a sampling system of a pressure transmitter. The pressure measurement system and the gas analysis system are integrally designed. By setting a sampling rake downstream of the combustion chamber, accurate measurement of the combustion chamber outlet pressure and gas component concentration can be achieved, as well as calculation of combustion performance such as the pressure loss coefficient, fuel-air ratio, pollutant emission index, combustion efficiency, and gas temperature. Compared with traditional combustion chamber performance measurement methods, the measurement and calculation methods provided by this patent only require setting a sampling rake downstream of the combustion chamber, which has less interference with the combustion chamber flow field and combustion performance, can also reduce the mutual influence between sensors, and improve the measurement accuracy of combustion performance. In addition, the measurement and calculation methods applicable to hydrogen combustion chamber performance are not affected and restricted by gas temperature and gas pressure, have a wider measurement range and higher measurement accuracy, can obtain combustion performance in a super-high temperature and high-pressure environment, and provide accurate data support for the optimization iteration and finalization of the combustion chamber.

[0016] Preferably, by adding a water remover and a dryer, water vapor in the sample gas can be effectively removed, avoiding interference with the gas analyzer and the pressure transmitter caused by too high water vapor content. In addition, after the sample gas is fully dehydrated, the accuracy of the concentration of the measured components can be guaranteed, and the accuracy of data post-processing can be improved.

[0017] Preferably, by setting a water-cooling structure and a first thermocouple in the sampling rake, the cooling water flow rate in the water-cooling structure can be controlled through temperature closed-loop control. On the one hand, it ensures sufficient cooling of the sampling rake by the external cooling system and avoids ablation of the sampling rake by high-temperature gas. On the other hand, through the electrical connection of the control unit with the first thermocouple and the external cooling system, precise temperature control is achieved, ensuring that the appropriate sampling temperature can not only freeze the chemical reaction rate in the sample gas but also prevent the liquefaction of water vapor in the sampling rake.

[0018] Preferably, by using electric tracing heat pipes and installing a second thermocouple, a third thermocouple, and a fourth thermocouple, the temperature in the first sample gas pipe, the second sample gas pipe, and the third sample gas pipe can be monitored in real time, and the first sampling pipe, the second sampling pipe, and the third sampling pipe can be controlled to perform heat preservation operations on the sample gas according to the temperature change, maintaining the sample gas temperature within a reasonable range. This not only helps prevent secondary reactions due to too high sample gas temperature, resulting in distortion of the sample gas component concentration, but also avoids liquefaction of water vapor, nitrogen dioxide, or other gases due to too low sample gas temperature through the electric tracing heat pipes.

[0019] The temperatures of the first thermocouple and the second thermocouple are maintained at 50 °C above the boiling point of water corresponding to the combustion chamber outlet pressure, ensuring that the sample gas temperature in the sampling rake and the first sample gas pipe is not lower than this temperature (50 °C above the boiling point of water corresponding to the combustion chamber outlet pressure). Since the water vapor content in the sample gas before the dryer is high and water vapor is the component with the highest boiling point among all gas components, as long as the gas temperature is controlled to be higher than 50 °C above the boiling point of water corresponding to the combustion chamber outlet pressure, liquefaction of the sample gas can be prevented, ensuring the smoothness of the sampling rake and the first sampling pipe and sufficient sample gas flow, and effectively freezing the sample gas to prevent secondary reactions of the sample gas during the sampling process, ensuring the accuracy of the gas analysis results.

[0020] The temperatures of the third thermocouple and the fourth thermocouple are maintained at 50 °C above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure, ensuring that the sample gas temperature in the second sample gas pipe and the third sample gas pipe is not lower than this temperature (50 °C above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure). Since there is basically no water vapor in the sample gas after passing through the water remover and the dryer and nitrogen dioxide is the component with the highest boiling point among the gas components after removing water vapor, as long as the gas temperature is controlled to be higher than 50 °C above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure, liquefaction of the sample gas can be prevented, ensuring the smoothness of the second sampling pipe and the third sampling pipe and sufficient sample gas flow, and effectively freezing the sample gas to prevent secondary reactions of the sample gas during the sampling process, ensuring the accuracy of the gas analysis results.

[0021] Preferably, by setting the signal line and the data post-processing unit, the measurement data of the pressure transmitter and the gas analyzer can be transmitted to the data post-processing unit for centralized processing, analysis and calculation; this design optimizes the data processing flow, improves the efficiency and accuracy of data processing, and is convenient for subsequent combustion chamber performance analysis.

[0022] Preferably, multi-point mixed sampling can avoid the non-uniformity of the gas component concentration and flow velocity distribution in the combustion chamber exhaust pipe, thus more effectively reflecting the overall condition of the gas in the combustion chamber and reducing the influence of deviation caused by local sampling; the reasonable layout interval of the sampling points (8 - 12 mm) can effectively cover the cross-section of the exhaust pipe, improving the reliability, uniformity and representativeness of the measurement results.

[0023] Preferably, the pressure guiding pipe is made of stainless steel pipe or copper pipe, which has good corrosion resistance and high temperature resistance, can ensure long-term stable operation in high temperature and high pressure environment, and avoid measurement errors or equipment damage caused by material problems.

[0024] Preferably, by sampling from the combustion chamber exhaust pipe and performing pressure maintenance, temperature reduction, water removal, and drying processes, the influence of a large amount of water vapor generated by hydrogen combustion liquefying near the wall surface downstream of the combustion chamber on data measurement can be overcome, and accurate total pressure and gas component data at the combustion chamber outlet can be obtained under relatively stable temperature and pressure conditions. Based on these real-time data, performance evaluation indicators of the hydrogen combustion chamber under different working conditions, such as pressure loss coefficient, pollutant emission index, combustion efficiency, and gas temperature, can be calculated in real time, providing comprehensive data support for the performance analysis of the hydrogen combustion chamber and contributing to the optimized design of the hydrogen combustion chamber.

[0025] Preferably, by measuring the component data of the combustion chamber oxidant (air) and combining the measurement results of the gas analyzer, it is possible to solve the NO, NOx pollutant emission indices and the emission index of H2, as well as calculate the combustion efficiency and gas temperature, relying on fewer measurement data and chemical equilibrium equations; the rationality of the sampling point and the accuracy of the measurement results can be evaluated by calculating the fuel-air ratio deviation; if the fuel-air ratio deviation exceeds the threshold, the sampling point position and anomaly detection are readjusted, sampling and analysis are performed again, and the fuel-air ratio deviation is calculated to ensure the reliability of the final result; by setting a 5% fuel-air ratio deviation threshold, the sampling and measurement errors can be effectively controlled, and the calculation accuracy of the pollutant emission index, combustion efficiency, and gas temperature can be ensured; this threshold is selected based on experience and is reasonably set, which can avoid unnecessary repeated measurements while ensuring that the measurement accuracy meets the engineering and technical requirements, improving the test efficiency. Brief Description of the Drawings

[0026] The drawings described herein are for illustrative purposes only and do not limit the scope of the disclosure of the present invention in any way. Additionally, the shapes and proportional dimensions of the components in the figures are only schematic and are used to assist in understanding the present invention, rather than specifically limiting the shapes and proportional dimensions of the components of the present invention. In the drawings: Figure 1 It is a schematic diagram of a gas analysis system suitable for a hydrogen combustion chamber described in the embodiment; Figure 2 It is a step diagram of a performance analysis method suitable for a hydrogen combustion chamber described in the embodiment.

[0027] Among them, 1. Combustion chamber; 2. Sampling rake; 3. Sampling point; 4. First sample gas pipe; 5. Water remover; 6. Dryer; 7. Second sample gas pipe; 8. Function conversion valve; 9. Pressure guiding pipe; 10. Third sample gas pipe; 11. Gas analyzer; 12. Pressure transmitter; 13. First signal line; 14. Second signal line; 15. Data post-processing unit; 16. First thermocouple; 17. Second thermocouple; 18. Third thermocouple; 19. Fourth thermocouple; 20. Control unit. Detailed Description of the Embodiment

[0028] In order to enable those skilled in the art to better understand the technical solutions in the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0029] It should be noted that when an element is referred to as "disposed on" another element, it can be directly on the other element or there may also be an intermediate element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be an intermediate element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are only for the purpose of illustration and do not represent the only embodiments.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the present invention. The terms used in the specification of the present invention herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more of the related listed items.

[0031] Embodiment 1 As Figure 1 shown, a gas analysis system applicable to a hydrogen combustion chamber includes a sampling rake 2, a first sample gas pipe 4, a water remover 5, a dryer 6, a second sample gas pipe 7, a function conversion valve 8, a third sample gas pipe 10, a gas analyzer 11, a pressure guiding pipe 9, and a pressure transmitter 12; the sampling rake 2 is installed downstream of the exhaust pipe of the combustion chamber 1, and the sampling rake 2 is sequentially connected to the intake end of the function conversion valve 8 through the first sample gas pipe 4, the water remover 5, the dryer 6, and the second sample gas pipe 7; one path of the exhaust end of the function conversion valve 8 is connected to the inlet of the gas analyzer 11 through the third sample gas pipe 10 for realizing the analysis and measurement of the gas component concentration; the other path of the exhaust end of the function conversion valve 8 is connected to the inlet of the pressure transmitter 12 through the pressure guiding pipe 9 for realizing the measurement of the outlet pressure of the combustion chamber 1.

[0032] Specifically, the sampling rake 2 adopts a multi-point mixing type sampling rake 2, which includes a plurality of sampling points 3, and the arrangement interval of the sampling points 3 is 8-12 mm; the sampling points 3 are reasonably arranged according to the gas component distribution and flow velocity distribution at the outlet of the combustion chamber 1 to ensure that the high-temperature gas at the outlet of the hydrogen combustion chamber 1 can be uniformly obtained.

[0033] The sample gas taken out by the sampling rake 2 enters the water eliminator 5 and the dryer 6 in sequence through the first sample gas pipe 4 for water removal and drying. The reason is that since hydrogen combustion causes a high proportion of water vapor in the combustion gas products, and even some water vapor has liquefied near the wall surface of the combustion chamber 1, resulting in the distortion of the component concentration in the taken-out sample gas. Therefore, in this embodiment, the water vapor in the sample gas is thoroughly removed through two-stage drying to ensure that the downstream gas measurement is no longer affected by the water vapor content and liquid water, maintaining the accuracy of the system measurement and the service life of the instrument and equipment.

[0034] The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes a first thermocouple 16 and a control unit 20; the first thermocouple 16 is arranged at the sample gas outlet position of the sampling rake 2; a water cooling structure is arranged in the sampling rake 2, and the water cooling structure is connected to an external cooling system. The cooling water flow rate passing through the water cooling structure is adjusted through the cooling system. The water cooling structure is used to cool the sampling rake 2 and cool down the sample gas in the sampling rake 2 to a suitable temperature; the control unit 20 is electrically connected to the first thermocouple 16 and the external cooling system respectively. The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes a second thermocouple 17; the second thermocouple 17 is arranged in the first sample gas pipe 4; the first sample gas pipe 4 adopts an electric tracing pipe; the control unit 20 is electrically connected to the second thermocouple 17 and the first sample gas pipe 4 respectively, and is used to control the electric tracing pipe to keep the sample gas in the first sample gas pipe 4 warm. The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes keeping the temperatures of the first thermocouple 16 and the second thermocouple 17 above the boiling point of water corresponding to the combustion chamber outlet pressure by 50 °C, ensuring that the sample gas temperature in the sampling rake 2 and the first sample gas pipe 4 is not lower than this temperature (above the boiling point of water corresponding to the combustion chamber outlet pressure by 50 °C). Because the water vapor content in the sample gas before the dryer 6 is high, and water vapor is the component with the highest boiling point among all combustion gas components. As long as the gas temperature is controlled above the boiling point of water corresponding to the combustion chamber outlet pressure by 50 °C, the liquefaction phenomenon of the sample gas can be prevented, ensuring the smoothness of the sampling rake and the first sampling pipe and sufficient sample gas flow rate, and effectively freezing the sample gas to prevent secondary reactions of the sample gas during the sampling process, ensuring the accuracy of the gas analysis result.

[0035] Because the boiling point of water changes with the air pressure level, the pressure of the sample gas at the combustion chamber outlet is the same as the combustion chamber outlet pressure, and the combustion chamber outlet pressure can be measured by the pressure transmitter 12 in this embodiment. Then the boiling point of water at this air pressure level can be calculated according to formula (1). Thus, the control target (50 °C above the boiling point of water) for the sample gas temperature at the outlet of the sampling rake 2 and in the first sample gas pipe 4 can be obtained.

[0036] T H2O =16.3872 / [3885.7 - ln(P)] - 230.17 (1) Among them, T is the boiling point of water, with the unit of °C; P is the absolute pressure at the combustion chamber outlet, with the unit of kPa.

[0037] The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes a third thermocouple 18 disposed in the second sample gas pipe 7; the second sample gas pipe 7 uses an electrically traced pipe; the control unit 20 is electrically connected to the third thermocouple 18 and the second sample gas pipe 7 respectively, and is used to control the electrically traced pipe to keep the sample gas in the second sample gas pipe 7 warm.

[0038] The function conversion valve 8 uses a pneumatic control valve.

[0039] The gas analyzer 11 is connected to the A exhaust end of the function conversion valve 8 through a third sample gas pipe 10. The gas analyzer 11 is used to measure the mole fractions of O2, CO2, NO, and NOx in the sample gas after water removal. The gas analyzer 11 is equipped with a standard sample gas calibration system to realize the regular calibration of the gas analyzer 11 and ensure the accuracy of the measurement results.

[0040] Optionally, the gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes a fourth thermocouple 19; the fourth thermocouple 19 is disposed in the third sample gas pipe 10; the control unit 20 is electrically connected to the fourth thermocouple 19 and the third sample gas pipe 10, and is used to control the electrically traced pipe to keep the sample gas in the third sample gas pipe 10 warm. The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes keeping the temperatures of the third thermocouple and the fourth thermocouple above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure by 50 °C, ensuring that the sample gas temperature in the second sample gas pipe 7 and the third sample gas pipe 10 is not lower than this temperature (50 °C above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure). Because there is basically no water vapor in the sample gas after passing through the water removal machine and the dryer, and nitrogen dioxide is the component with the highest boiling point in the gas components after removing water vapor. As long as the gas temperature is controlled to be above 50 °C above the boiling point of nitrogen dioxide corresponding to the combustion chamber outlet pressure, the liquefaction phenomenon of the sample gas can be prevented, ensuring the smoothness of the second sampling pipe 7 and the third sampling pipe 10 and sufficient sample gas flow, and effectively freezing the sample gas to prevent secondary reactions of the sample gas during the sampling process, ensuring the accuracy of the gas analysis results.

[0041] Because the boiling point of nitrogen dioxide changes with the air pressure level, the sample gas passing through the first sample gas pipe 4, the second sample gas pipe 7, and the third sample gas pipe 10 is at the combustion chamber outlet pressure level (the first sample gas pipe 4, the second sample gas pipe 7, and the third sample gas pipe 10 can all maintain pressure). The combustion chamber outlet pressure can be measured by the pressure transmitter 12. Then, the boiling point of nitrogen dioxide at this air pressure level can be calculated according to formula (2). Thus, the control target (50 °C above the boiling point of nitrogen dioxide) of the sample gas temperature in the above-mentioned second sampling pipe 7 and the third sampling pipe 10 can be obtained.

[0042] T NO2= 1256.1 / [4.0062 - lg(P)] - 218.52 (2) Preferably, as Figure 1 shown, the pressure guiding pipe 9 between the exhaust end B of the function conversion valve 8 and the pressure transmitter 12 is made of stainless steel pipe or red copper pipe for pressure maintenance and temperature reduction, so as to prevent the sample gas temperature from exceeding the temperature requirement range of the pressure transmitter 12, and improve the measurement accuracy and service life of the pressure transmitter 12.

[0043] As described above, the gas analyzer 11 is connected to the A exhaust end of the function conversion valve 8 through the third sample gas pipe 10. The gas analyzer 11, as Figure 1 shown.

[0044] Optionally, the third sample gas pipe 10 adopts an electric tracing heat pipe to keep the temperature of the sample gas after water removal continuously higher than the boiling point of nitrogen dioxide under the air pressure condition in the third sample gas pipe 10, so as to prevent the sample gas from condensing into liquid and flowing into the gas analyzer 11; The gas analysis system applicable to the hydrogen combustion chamber in this embodiment further includes a fourth thermocouple 19; The fourth thermocouple 19 is arranged in the third sample gas pipe 10; The control unit 20 is electrically connected to the fourth thermocouple 19 and is used to guide the electric tracing heat pipe to keep the temperature of the third sample gas pipe 10.

[0045] A gas analysis system applicable to a hydrogen combustion chamber further includes a first signal line 13, a second signal line 14 and a data post-processing unit 15; One end of the first signal line 13 is electrically connected to the pressure transmitter 12, and the other end of the first signal line 13 is electrically connected to the data post-processing unit 15; One end of the second signal line 14 is electrically connected to the gas analyzer 11, and the other end of the second signal line 14 is electrically connected to the data post-processing unit 15.

[0046] Specifically, the data post-processing unit 15 collects the data of the pressure transmitter 12 and the gas analyzer 11 through signal line transmission, and obtains performance indicators such as the pressure loss coefficient of the combustion chamber 1, the fuel-air ratio of gas analysis, the pollutant emission index, the combustion efficiency, and the gas temperature through post-processing methods.

[0047] The present invention samples from the exhaust pipe of the combustion chamber 1 to ensure that a true sample of the combustion gas in the combustion chamber 1 can be obtained, providing a reliable data source for subsequent measurements and analyses. By obtaining data through the pressure transmitter 12 and the gas analyzer 11, the total pressure at the outlet of the combustion chamber 1 and the mole fractions of key products (O2, CO2, NO, and NOx) in the combustion gas can be accurately measured. These real-time data are crucial for evaluating the performance of the combustion chamber 1. From the perspective of chemical reactions, a method for calculating combustion performance such as the fuel-air ratio, pollutant emissions, combustion efficiency, and combustion gas temperature of the combustion gas is provided, and the representativeness of the sampling results and the accuracy of the measurement of the combustion gas component concentration can be evaluated through the deviation of the fuel-air ratio of the combustion gas analysis, thereby obtaining accurate performance parameters of the combustion chamber 1 and providing data support for the improvement and design of the hydrogen combustion chamber 1.

[0048] As Figure 2 shown, a method for performance analysis applicable to a hydrogen combustion chamber includes the following steps: sampling from the exhaust pipe of the combustion chamber 1; subjecting the collected combustion gas to pressure reduction, temperature reduction, water removal, and drying, then measuring the total pressure at the outlet of the combustion chamber 1 with the aid of the pressure transmitter 12, and then measuring the mole fractions of key products in the sample gas with the aid of the gas analyzer 11; obtaining the pressure loss coefficient based on the total pressure at the outlet of the combustion chamber 1 and the measured total pressure at the inlet of the combustion chamber 1; measuring the data of the oxidant (air) component of the combustion chamber and solving the pollutant emission indices of NO and NOx and the emission index of H2 in combination with the mole fractions of the key products measured by the gas analyzer 11; calculating the combustion efficiency by combining the emission indices of H2 and NO and the lower calorific value of H2; calculating the combustion gas temperature based on the obtained combustion efficiency, the lower calorific value of H2, and the number of moles of reactants and products.

[0049] Specifically, the measurement obtains the component data of the oxidant (air) in the combustion chamber, and combines the data measured by the gas analyzer 11 to solve the pollutant emission indices of NO and NOx and the emission index of H2, and calculates the combustion efficiency and the gas temperature, including the following steps: measuring the volume fractions of the key components of the oxidant (air) in the combustion chamber; obtaining the mole fractions of O2, CO2, NO, and NOx in the sample gas based on the gas analyzer 11; establishing a system of equations based on the chemical equilibrium equation to solve the number of moles of reactants and products; calculating the fuel-air ratio of the gas analysis and comparing it with the physically measured fuel-air ratio. If the absolute value of the relative deviation between the two is not greater than 5%, it proves that the arrangement of the sampling point 3, the transport of the sample gas, and the analysis results of the component concentrations are accurate, and the performance parameters such as pollutant emission indices, combustion efficiency, and gas temperature can be calculated; if the relative deviation between the two is greater than 5%, it is necessary to adjust the position of the sampling point 3 on the sampling rake 2, check the sealing performance of the first sample gas pipe 4, the water eliminator 5, the dryer 6, the second sample gas pipe 7, the function conversion valve 8, and the third sampling pipe, calibrate the gas analyzer 11 with a standard sample gas, and then re-conduct sampling analysis and data processing until the fuel-air ratio deviation is less than 5%.

[0050] A method for analyzing the performance of a hydrogen combustion chamber in this embodiment is as follows: During the performance test of the hydrogen combustion chamber 1, first close the function conversion valve 8. After the combustion state is stable, open the function conversion valve 8 to the B exhaust end, and lead out the gas pressure through the sampling rake 2, the first sample gas pipe 4, the water eliminator 5, the dryer 6, the second sample gas pipe 7, and the pressure guiding pipe 9. The pressure transmitter 12 measures the exhaust pressure of the combustion chamber 1 led out, and transmits the pressure data to the data post-processing unit 15 through the first signal line 13 for calculating the total pressure loss coefficient of the combustion chamber 1. The calculation method is shown in formula (3).

[0051] ε = (P out - P in ) / P in (3) Where, ε is the total pressure loss coefficient of the combustion chamber 1, P out is the total pressure at the outlet of the combustion chamber 1, and P in is the total pressure at the inlet of the combustion chamber 1.

[0052] After completing the measurement of the total pressure at the outlet of the combustion chamber 1 under this operating condition, switch the function conversion valve 8 to the A exhaust end, and continuously extract the sample gas after hydrogen fuel combustion through the sampling rake 2, the first sample gas pipe 4, the water eliminator 5, the dryer 6, the second sample gas pipe 7, and the third sample gas pipe 10. The key component concentrations of the sample gas are measured in real time by the gas analyzer 11 to obtain the mole fractions of the O2, CO2, NO, and NOx components, and the measurement results of the gas analyzer 11 are transmitted to the data post-processing unit 15 through the second signal line 14 for calculating the fuel-air ratio, pollutant emission index, combustion efficiency, and gas temperature of the combustion chamber 1 gas analysis.

[0053] Based on the chemical equilibrium equation (4), the following system of equations (5) is established: H2 + X[A(O2) + B(N2) + C(CO2) + h(H2O)] → P1(H2O) + P2(H2) + P3(CO2) + P4(N2) + P5(O2) + P6(NO) + P7(NO2) (4) The system of equations (5) includes 9 equations, as follows: Carbon element conservation equation: CX = P3 Hydrogen element conservation equation: 2 + 2hX = 2P1 + 2P2 Nitrogen element conservation equation: 2BX = P6 + P7 Oxygen element conservation equation: 2AX + 2CX + hX = P1 + 2P3 + 2P5 + P6 + 2P7 Carbon dioxide measurement equation: [CO2] = P3 / (P t - P1) Oxygen measurement equation: [O2] = P5 / (Pt - P1) Nitric oxide measurement equation: [NO] = P6 / (P t - P1) Nitrogen oxides measurement equation: [NOx] = (P6 + P7) / (P t - P1) Total conservation equation: P t = P1 + P2 + P3 + P4 + P5 + P6 + P7 Through the above 9 equations, X, P1~P7, P tThere are a total of 9 unknowns. Among them, the component ratios A, B, C, and h of air, which are the mole fractions of O2, N2, CO2, and H2O in air respectively, can be obtained by measurement with a chromatograph. Among them, H2 is the fuel, X is the number of moles of the oxidizer (air) in the reactants, and P1, P2, ..., P7 represent the number of moles of H2O (water vapor), H2 (hydrogen), CO2 (carbon dioxide), N2 (nitrogen), O2 (oxygen), NO (nitric oxide), and NO2 (nitrogen dioxide) respectively. [CO2], [O2], [NO], and [NOx] represent the mole fractions of carbon dioxide, oxygen, nitric oxide, and nitrogen oxides measured respectively; P t is the total number of moles of all products.

[0054] The fuel-air ratio of the combustion gas in the hydrogen combustion chamber 1 under this operating condition is calculated by chemical calculation method, and the calculation method is shown in formula (6).

[0055] FAR CAL = M H2 / (X * M air )(6) Among them, FAR CAL is the mass ratio of hydrogen fuel to the oxidizer (air), M H2 is the molar mass of hydrogen, X is the number of moles of the oxidizer (air) in the reactants, and Mair is the molar mass of the oxidizer (air).

[0056] Subsequently, before calculating the combustion performance parameters, the representativeness of the sampling results and the accuracy of the component concentrations of the sampled gas are evaluated. The fuel-air ratio obtained by gas analysis is compared with the fuel-air ratio measured physically. If the absolute value of the relative deviation between the two is not greater than 5%, it proves that the arrangement of sampling point 3, the transportation of the sampled gas, and the analysis results of the component concentrations are accurate, and the combustion efficiency, pollutant emission index, and exhaust gas temperature performance parameters can be calculated; if the relative deviation between the two is greater than 5%, it is necessary to adjust the position of sampling point 3 on the sampling rake 2, check the tightness of the first sampled gas pipe 4, the water separator 5, the dryer 6, the second sampled gas pipe 7, the function conversion valve 8, and the third sampling pipe 10, and calibrate the gas analyzer 11 with a standard sampled gas. Subsequently, sampling analysis and data processing are carried out again until the fuel-air ratio deviation is less than 5%. Among them, the fuel-air ratio obtained by gas analysis is obtained by calculation, and the fuel-air ratio measured physically is obtained by measuring with a hydrogen mass flowmeter and an air mass flowmeter installed on the test bench. The calculation method of the fuel-air ratio deviation is shown in formula (7): β = |(FAR MEA - FAR CAL ) / FAR MEA |(7) FAR MEAThe fuel-air ratio measured actually is Fuel-Air Ratio Measured, FAR CAL The fuel-air ratio calculated is Fuel-Air Ratio Calculated, and β is FAR CAL and FAR MEA is the absolute value of the deviation therebetween.

[0057] When the representativeness of the sampling result and the accuracy of the sampled gas component concentration meet the requirements, the pollutant emission index, combustion efficiency and gas temperature of the hydrogen combustion chamber 1 under this operating condition are calculated successively by chemical calculation methods. The calculation method of the pollutant emission index is shown in Formulas (8) and (9), the calculation formula of the hydrogen emission index is shown in (10), and the calculation method of the combustion efficiency is shown in Formula (11).

[0058] EINO = P6 * M NO * 1000 / M H2 (8) EINOx = (P6 * M NO + P7 * M NO2 ) * 1000 / M H2 (9) EIH2 = 1000 * P2 (10) η = 1 - (120,900 * EIH2 + 3,013 * EINO) / LHV H2 (11) Among them, EINO is the emission index of nitrogen monoxide (NO), P6 is the number of moles of NO in the product (mol); M NO is the molar mass of NO, 30 g / mol; M H2 is the molar mass of hydrogen, 2 g / mol.

[0059] Among them, EINOx is the emission index of nitrogen oxides (NOx); P7 is the number of moles of NO2 in the product (mol); M NO2 is the molar mass of NO2, 46 g / mol.

[0060] Among them, EIH2 is the emission index of hydrogen (H2); P2 is the number of moles of H2 in the product (mol).

[0061] Among them, η is the combustion efficiency; LHV H2 is the lower heating value of hydrogen.

[0062] When calculating the outlet temperature of the combustion chamber 1, first establish an enthalpy conservation equation based on the stoichiometric calculation method, as shown in Equation (12). Since the enthalpies of air and fuel on the reactant side are known, the outlet gas temperature of the hydrogen combustion chamber 1 can be obtained by solving the enthalpy conservation equation. The enthalpies of the components on the product side are actually univariate polynomials of the outlet temperature of the combustion chamber 1, and the mathematical relationship can be briefly summarized as Formula (13).

[0063] X*M air *I air + X*M H2 *I H2 +η*X*M H2 *LHV H2 =P1*M H2O *I H2O +P2*M H2 *I H2 +P3*M CO2 *I CO2 +P4*M N2 *I N2 +P5*M O2 *I O2 + P6*M NO *I NO +P7*M NO2 *I NO2 (12) I*=f(T out )(13) Wherein, X is the number of moles of the oxidant (air) in the reactants; Mair is the molar mass of the oxidant (air); Iair is the specific enthalpy of the oxidant (air); M H2 is the molar mass of hydrogen; I H2 is the specific enthalpy of the fuel; η is the combustion efficiency; LHV H2 is the lower heating value of hydrogen; P i is the number of moles of the product i; M i is the molar mass of the product i; I i is the specific enthalpy of the product i. Wherein, I * is the specific enthalpy of the product; T out is the gas temperature.

[0064] The advantages of the gas analysis system and performance analysis method of the hydrogen combustion chamber for gas analysis of the present invention are summarized as follows: (1) Existing gas analysis system methods are all designed based on aviation kerosene combustion chambers. Their gas components mainly consist of gas components, which are completely different from the gas components of hydrogen combustion chambers. After hydrogen combustion, the proportion of water vapor in the gas is very high, and some water vapor has condensed near the combustion chamber wall surface. On the one hand, it causes the component concentration in the sampled gas to be distorted. On the other hand, the water vapor content in the sampled gas is too high, and the water analyzer cannot accurately measure it, resulting in no reference for the water vapor content in the sampled gas and unable to perform data post-processing. In addition, it is easy to cause blockage of the sampling pipe, thus affecting the sampling effect and the rapid response of the gas analysis system. This invention patent designs a gas analysis system applicable to hydrogen combustion chambers aiming at the characteristic of too high water vapor content in the gas components after hydrogen combustion, and by setting an appropriate sampling temperature, it can not only ensure the freezing of chemical reactions and avoid secondary reactions, but also prevent the liquefaction of water vapor in the sampling rake and sampling pipe, and accurately measure the gas component concentration of the hydrogen combustion chamber through a multi-stage water removal method.

[0065] (2) Existing post-processing methods for gas analysis are only applicable to hydrocarbon fuels with a relatively small proportion of water vapor. The gas components after the combustion of hydrocarbon fuels are completely different from those after hydrogen combustion. Moreover, when calculating the combustion efficiency by existing gas analysis methods, only carbon monoxide and unburned hydrocarbons are considered, and these two components do not exist at all in hydrogen combustion, which leads to the inapplicability of its post-processing methods. For this reason, based on the typical gas component composition after hydrogen combustion and the characteristics of the gas analysis system applicable to hydrogen combustion chambers, this invention patent optimizes and establishes a data post-processing method applicable to hydrogen combustion chambers to accurately calculate the pollutant emission index, combustion efficiency, and gas temperature, providing a new method for evaluating the performance of hydrogen combustion chambers.

[0066] (3) A gas analysis system and performance analysis method applicable to hydrogen combustion chambers proposed by this invention integrate the pressure measurement system and the gas analysis system. By setting a sampling rake downstream of the combustion chamber, accurate measurement of the combustion chamber outlet pressure and gas component concentration can be achieved, as well as the calculation of combustion performance such as the pressure loss coefficient, fuel-air ratio, pollutant emission index, combustion efficiency, and gas temperature. Compared with traditional combustion chamber performance measurement methods, the measurement and calculation methods provided by this patent only need to set a sampling rake downstream of the combustion chamber, which has less interference with the combustion chamber flow field and combustion performance, can also reduce the mutual influence between sensors, and improve the measurement accuracy of combustion performance. In addition, the performance measurement and calculation methods applicable to hydrogen combustion chambers are not affected and restricted by gas temperature and gas pressure, have a wider measurement range and higher measurement accuracy, and can obtain combustion performance in a super-high temperature and high-pressure environment, providing accurate data support for the optimization iteration and finalization of the combustion chamber.

[0067] The above embodiments are merely one of the implementation manners capable of implementing the technical solution of the present invention. The scope of protection required by the present invention is not only limited by this embodiment, but also includes any changes, substitutions and other implementation manners that are easily conceivable by those skilled in the art within the technical scope disclosed by the present invention. Although the embodiments of the present invention have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. The scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A gas analysis system applicable to a hydrogen combustion chamber, characterized in that, It includes a sampling rake (2), a first sample gas pipe (4), a function conversion valve (8), a third sample gas pipe (10), a gas analyzer (11), a pressure guiding pipe (9), and a pressure transmitter (12); the sampling rake (2) is arranged downstream of the exhaust pipe of the combustion chamber (1), and the sampling rake (2) is connected to the intake end of the function conversion valve (8) through the first sample gas pipe (4); one path of the exhaust end of the function conversion valve (8) is connected to the inlet end of the gas analyzer (11) through the third sample gas pipe (10) to realize the analysis and measurement of the gas component concentration; the other path of the exhaust end of the function conversion valve (8) is connected to the inlet end of the pressure transmitter (12) through the pressure guiding pipe (9) to realize the measurement of the outlet pressure of the combustion chamber (1).

2. The gas analysis system applicable to a hydrogen combustion chamber according to claim 1, wherein It further includes a water separator (5), a dryer (6), and a second sample gas pipe (7); the water separator (5), the dryer (6), and the second sample gas pipe (7) are sequentially arranged between the first sample gas pipe (4) and the intake end of the function conversion valve (8), and the water separator (5) is connected to the first sample gas pipe (4).

3. A gas analysis system applicable to a hydrogen combustion chamber according to claim 2, characterized in that, It further includes a first thermocouple (16) and a control unit (20); the first thermocouple (16) is arranged at the sample gas outlet position of the sampling rake (2); a water cooling structure is arranged in the sampling rake (2), and the water cooling structure is connected to an external cooling system, and the water cooling structure is used to cool the sampling rake (2) and the sample gas inside it; the control unit (20) is electrically connected to the first thermocouple (16) and the external cooling system respectively.

4. A gas analysis system applicable to a hydrogen combustion chamber according to claim 3, characterized in that, It further includes a second thermocouple (17); the second thermocouple (17) is arranged in the first sample gas pipe (4), and the first sample gas pipe (4) is an electrically heated tracing pipe; the control unit (20) is electrically connected to the second thermocouple (17) and the first sample gas pipe (4) to guide the electrically heated tracing pipe to heat-insulate the first sample gas pipe (4).

5. A gas analysis system applicable to a hydrogen combustion chamber according to claim 3, characterized in that, It further includes a third thermocouple (18) and a fourth thermocouple (19); the third thermocouple (18) is arranged in the second sample gas pipe (7), and the fourth thermocouple (19) is arranged in the third sample gas pipe (10); both the second sample gas pipe (7) and the third sample gas pipe (10) are electrically heated tracing pipes; the control unit (20) is electrically connected to the third thermocouple (17), the fourth thermocouple (19), the second sample gas pipe (7), and the third sample gas pipe (10) respectively to guide the electrically heated tracing pipe to heat-insulate the sample gas flowing through the second sample gas pipe (7) and the third sample gas pipe (10).

6. The gas analysis system applicable to a hydrogen combustion chamber according to claim 1, characterized in that, It further includes a first signal line (13), a second signal line (14), and a data post-processing unit (15); one end of the first signal line (13) is electrically connected to the pressure transmitter (12), and the other end of the first signal line (13) is electrically connected to the data post-processing unit (15); one end of the second signal line (14) is electrically connected to the gas analyzer (11), and the other end of the second signal line (14) is electrically connected to the data post-processing unit (15).

7. The gas analysis system applicable to a hydrogen combustion chamber according to claim 1, characterized in that, The sampling rake (2) is a multi-point mixing type sampling rake (2), and a plurality of sampling points (3) are evenly arranged on the sampling rake (2), and the interval between the sampling points (3) is 8 - 12 mm.

8. The gas analysis system applicable to a hydrogen combustion chamber according to claim 1, characterized in that, The pressure guiding pipe (9) is made of stainless steel pipe or copper pipe.

9. A performance analysis method applicable to a hydrogen combustion chamber, characterized in that It includes the following steps: Sampling is carried out from the exhaust pipe of the combustion chamber (1); The collected fuel gas is kept under pressure and cooled, and water is removed and dried. Then, the total pressure at the outlet of the combustion chamber (1) is measured by means of a pressure transmitter (12), and the mole fraction of key products is measured by means of a fuel gas analyzer (11); Based on the total pressure at the outlet of the combustion chamber (1) and the measured total pressure at the inlet of the combustion chamber (1), the pressure loss coefficient is obtained; The component data of the oxidant in the combustion chamber are measured, and the pollutant emission indexes of NO and NOx and the emission index of H2 are solved in combination with the mole fraction of the products measured by the fuel gas analyzer (11); Combined with the emission indexes of H2 and NO and the lower calorific value of H2, the combustion efficiency is calculated; Based on the obtained combustion efficiency, the lower calorific value of H2, and the number of moles of reactants and products, the fuel gas temperature is calculated; 10. A performance analysis method applicable to a hydrogen combustion chamber according to claim 9, characterized in that, The measured component data of the oxidant in the combustion chamber, combined with the data measured by the fuel gas analyzer (11), solve the pollutant emission indexes of NO and NOx and the emission index of H2, and calculate the combustion efficiency and the fuel gas temperature, including the following steps: Measure the volume fraction of the key components of the oxidant in the combustion chamber; Based on the fuel gas analyzer (11), obtain the mole fractions of O2, CO2, NO, and NOx in the sample gas; Establish a system of equations based on the chemical equilibrium equation to solve the elemental mole numbers of reactants and products; Calculate the fuel-air ratio of the fuel gas analysis and compare it with the physically measured fuel-air ratio. If the deviation between the calculated fuel-air ratio and the physically measured fuel-air ratio exceeds the threshold, re-adjust the sampling point position and abnormal detection. Based on the fuel gas analyzer (11), obtain the mole fractions of O2, CO2, NO, and NOx in the sample gas after adjusting the sampling point, and perform the foregoing steps in sequence, cycling until the fuel-air ratio deviation is less than or equal to the threshold; the threshold is 5%.

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