A method and platform for testing performance of an engine turbocharging system

Abstract

The present application belongs to the technical field of internal combustion engine performance test and fluid mechanics experiment, and discloses a kind of engine turbocharging system performance test method and platform.The method comprises: test environment construction, test platform building is carried out;Working substance synthesis and conditioning, phase change flow field monitoring, data correction and calculation, risk assessment.The present application discards the traditional ideal gas assumption, introduces actual gas model and latent heat correction algorithm, eliminates the interference of thermal throttling effect on efficiency calculation, significantly improves the reliability of test data.In addition, the present application introduces optical droplet monitoring and water erosion evaluation in the test process.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine performance testing and fluid dynamics experimental technology, and particularly relates to a method and platform for testing the performance of an engine turbocharger system. Background Technology

[0002] With the transformation of the global energy structure, zero-carbon fuel engines such as hydrogen internal combustion engines (H2-ICE) have become an important technological path for decarbonization in the transportation sector, especially for heavy-duty commercial vehicles, due to their advantages of zero carbon emissions and high reliability. As a core component for increasing engine power density, the turbocharger's matching performance directly determines the engine's thermal efficiency. However, hydrogen internal combustion engines differ fundamentally from traditional hydrocarbon fuel engines in their exhaust composition. According to relevant research, hydrogen combustion products have a high water vapor content, and the exhaust has a high dew point temperature. During the high-speed expansion process of the turbocharger (within the nozzle ring and impeller flow channel), the high-humidity exhaust undergoes a rapid cooling and depressurization process, and the airflow may enter a supersaturated state. When the supercooling reaches a certain threshold, non-equilibrium spontaneous condensation occurs, instantly generating a large number of tiny droplets and releasing latent heat of phase change.

[0003] The existing Chinese invention patent, "A Test Bench and Test Method for a Hydrogen Internal Combustion Engine Turbocharger" (Publication No. CN117571324A, Publication Date 20240220), mainly focuses on the convenience of mechanical clamping of the test bench and the lubricating oil recovery structure, but does not involve the influence of the special thermodynamic processes of the hydrogen internal combustion engine on the performance testing principle.

[0004] The existing technology, Chinese invention patent CN115541244A, published on 20221230, describes a test bench and test method for a hydrogen internal combustion engine turbocharger. This solution directly connects the exhaust end of the hydrogen internal combustion engine to the intake end of the turbine, using the real high-temperature gas generated by the hydrogen internal combustion engine to drive the turbine to do work, thus solving the problem of the working fluid composition not matching reality. However, this invention relies on the natural exhaust of the hydrogen internal combustion engine to drive the turbine, making it difficult to independently adjust the water vapor mole fraction in the exhaust within a wide range, and thus unable to systematically study the influence of different humidity levels on the turbocharger performance.

[0005] Existing turbocharger testing methods (such as GB / T 23341 or conventional gas test benches) typically use dry air or natural gas as the driving fluid, which cannot reproduce the high-humidity characteristics of exhaust gas from zero-carbon fuel engines such as hydrogen internal combustion engines. Furthermore, existing tests calculate efficiency based on the ideal gas assumption. Under high humidity conditions, the latent heat released by water vapor condensation heats the supersonic airflow, causing an abnormally high turbine outlet temperature. This results in an underestimation of the efficiency calculated using traditional formulas and an inability to accurately assess the reduction in blocked flow. In addition, due to the lack of real-time monitoring methods for condensate droplet size and content, existing testing methods cannot assess the risk of impact erosion from high-speed droplets on impeller blades and the outlet diffuser.

[0006] Therefore, there is an urgent need for a testing method that can simulate a high-humidity exhaust environment and perform real-time monitoring and data correction of unbalanced condensation flow in order to obtain the true performance of engine turbochargers. Summary of the Invention

[0007] To overcome the problems existing in related technologies, the present invention discloses an engine turbocharger system performance testing method and platform, specifically relating to a hydrogen fuel cell engine turbocharger performance testing method. The purpose of this invention is to solve the technical problems in the prior art that ignore the high humidity and phase change characteristics of engine exhaust, leading to inaccurate turbine efficiency measurements and unknown water erosion risks, and to provide a hydrogen fuel cell engine turbocharger performance testing method that considers the non-equilibrium condensation effect.

[0008] The technical solution is as follows: A performance testing method for an engine turbocharger system. This method addresses the non-equilibrium condensation phenomenon caused by high water vapor content in engine turbine exhaust. It achieves high-precision testing of turbine performance parameters and blade water erosion risk assessment through in-situ monitoring of the phase change flow field coupled with thermodynamic performance correction. Specifically, it includes the following steps:

[0009] S1, Experimental environment setup, construction of the experimental platform;

[0010] S2, working fluid synthesis and conditioning, controls the fuel supply and independently adjusts the temperature and humidity of the air entering the hydrogen engine through the intake conditioning device to drive the hydrogen engine to run, and generates hydrogen exhaust working fluid with target fuel-air ratio and water vapor mole fraction at the turbine inlet channel.

[0011] S3, Phase Change Flow Field Monitoring, during the turbine expansion and power generation process, simultaneously collects dynamic pressure and temperature data of the turbine's inlet and outlet channels, and uses an optical droplet detection device to obtain droplet light scattering signals or particle size distribution data in the exhaust gas of the outlet channel.

[0012] S4, Data Correction and Calculation: The main control computer calls the preset actual gas state model of hydrogen combustion products. Based on the collected dynamic pressure and temperature data of the turbine inlet and outlet channels, combined with droplet light scattering signals or particle size distribution data, it determines whether non-equilibrium condensation occurs in the exhaust gas during turbine expansion. Based on the latent heat of phase change of the condensed water vapor, it corrects and calculates the turbine's gas density, effective specific heat, mass flow rate, polytropic efficiency, and characteristic flow velocity parameters in the turbine channel.

[0013] S5, Risk Assessment: Based on the acquired droplet light scattering signal or particle size distribution data, and the corrected calculated turbine outlet average flow velocity, blade relative inflow velocity, or local characteristic flow velocity parameters, combined with droplet size and relative impact velocity, the water erosion risk level of the turbine blade surface is assessed.

[0014] Furthermore, in step S2, the range of water vapor mole fraction is controlled to be 15%-35%.

[0015] Furthermore, in step S3, the optical droplet detection device employs light scattering or laser Doppler technology, and the monitoring indicators include the droplet Sauter mean diameter (SMD) and the liquid water content (LWC).

[0016] Furthermore, in step S4, the actual gas state model adopts the IAPWS-95 standard to calculate the true enthalpy and entropy values ​​of the humid mixed gas.

[0017] Furthermore, the correction and calculation are as follows: If an increase in the outlet static temperature is detected and the optical droplet detection device detects a droplet signal, the latent heat release of the phase change is calculated using the energy conservation equation. The false temperature rise caused by this latent heat is subtracted from the total enthalpy at the outlet to obtain the true enthalpy drop caused by the work done by the gas flow expansion. The specific steps are as follows:

[0018] S401, Detect condensation: If the optical signal indicates the presence of droplets, and the outlet measured temperature... Higher than the theoretical adiabatic expansion temperature;

[0019] S402, Latent heat deduction: When water vapor condenses into droplets, it releases latent heat of vaporization. According to the law of conservation of energy, we have:

[0020]

[0021] In the formula, The specific enthalpy per unit mass of the hydrogen combustion exhaust gas working fluid at the turbine inlet. This refers to the specific enthalpy per unit mass of the uncondensed gas phase component at the turbine outlet. For the droplet humidity fraction, This refers to the effective work done per unit mass of the turbine during its actual expansion process.

[0022] The equivalent dry gas temperature without latent heat heating is calculated, and the true enthalpy drop is determined. ;

[0023] S403, efficiency correction, calculates the variable efficiency of the turbine based on the actual enthalpy drop, eliminating efficiency calculation errors caused by latent heat of phase change.

[0024] Furthermore, in the risk assessment of step S5, the system uses the average droplet size detected optically. The magnitude and the calculated average outlet velocity Calculate the Weber number of the droplet. The expression is:

[0025]

[0026] In the formula, For droplet density, Surface tension;

[0027] Based on this, a water erosion risk level report is generated, if the Weber number... If the droplet impact intensity exceeds the critical value, it will cause fatigue erosion of the blade and trigger an alarm.

[0028] Furthermore, after step S5, by adjusting the volume of the variable volume pressure stabilizing cavity on the inlet flow channel, the test mode is switched between steady-state flow test mode and pulsating flow test mode to compare the starting position of the condensation shock wave under different pulsating frequencies.

[0029] An engine turbocharger system performance testing platform, the platform comprising:

[0030] The air intake conditioning unit includes an air compressor, a filter, a temperature control box, a humidifier, and a pressure stabilizing box connected in sequence. Air passes through the air compressor, filter, and temperature control box. The air, whose temperature is controlled by the temperature control box, enters the humidifier where steam is added. The humidified steam enters the pressure stabilizing box and is then fed into the hydrogen engine.

[0031] The high-pressure hydrogen cylinder group, high-pressure hydrogen is sequentially sent into the hydrogen engine through a pressure reducing valve, a mass flow meter, a flame arrester, and a hydrogen injection rail;

[0032] The hydrogen-gas mixture inside the hydrogen engine enters the turbine through the inlet channel and the variable volume pressure stabilizing chamber;

[0033] The dynamic sensor group includes an inlet temperature sensor, an inlet pressure sensor, an outlet temperature sensor, and an outlet pressure sensor.

[0034] An inlet temperature sensor and an inlet pressure sensor are installed on the inlet flow channel;

[0035] The hydrogen combustion exhaust gas after turbine combustion passes sequentially through the outlet flow channel, exhaust condenser, exhaust analyzer, and exhaust pipe;

[0036] An outlet temperature sensor and an outlet pressure sensor are installed on the outlet flow channel;

[0037] An optical droplet detection device is installed near the turbine impeller in the outlet flow channel. The optical droplet detection device includes a photoelectric receiver, an optical observation window, and a laser emitter.

[0038] An optical observation window is located in the outlet flow channel near the turbine impeller. A laser emitter is installed in the optical observation window, and the laser emitter is connected to a photoelectric receiver.

[0039] Furthermore, the temperature and pressure information detected by the imported temperature sensor and the imported pressure sensor is sent to the data acquisition unit;

[0040] The temperature and pressure information detected by the outlet temperature sensor and outlet pressure sensor is sent to the data acquisition unit.

[0041] The photoelectric receiver sends the detected optical droplet information to the data acquisition unit; the data acquisition unit then sends all the collected data to the main control computer.

[0042] Furthermore, air enters the compressor through the air filter and air inlet, and after being compressed by the compressor, it is sent to the turbine and mixed with the hydrogen mixture. The hydrogen mixture is burned in the turbine to do work, and the exhaust gas produced flows through the electronically controlled back pressure valve and the silencer before being discharged into the atmosphere.

[0043] Combining all the above technical solutions, the beneficial effects of this invention are as follows:

[0044] First, this invention independently controls the temperature and humidity of the incoming air through intake conditioning, generating high-humidity pulsating exhaust with a specific water vapor molar fraction at the exhaust end; it utilizes an optical detection device installed at the turbine outlet to detect non-equilibrium condensate droplets in real time; and it corrects the collected thermodynamic parameters based on the actual gas law and a non-equilibrium phase change model, deducting efficiency losses caused by thermal throttling effects. This invention solves the problem of existing tests neglecting the high humidity and phase change characteristics of engine exhaust, and can accurately assess the true turbine efficiency and water erosion risk under wet steam conditions.

[0045] Secondly, this invention accurately reproduces the thermodynamic state of engine exhaust, particularly the high-humidity non-equilibrium condensation environment, by combining intake air conditioning with actual engine combustion. Simultaneously, this invention abandons the traditional ideal gas assumption, introducing a real gas model and latent heat correction algorithm to eliminate the interference of thermal throttling effects on efficiency calculations, significantly improving the reliability of test data. Furthermore, this invention introduces optical droplet monitoring and water erosion assessment into the testing process, filling a gap in engine turbocharger reliability testing.

[0046] Third, this invention can be directly applied to the research and development and testing phases of engines and their turbocharger systems. It helps to identify performance deviations and blade water erosion risks caused by water vapor condensation in advance during the prototype stage, thereby reducing the costs of repeated testing and structural rework in later stages. A search reveals that existing performance testing methods for turbocharger systems are mainly geared towards traditional internal combustion engines or gas turbine operating conditions, typically assuming a single gas phase exhaust medium. No dedicated testing methods have been found for high water vapor content and non-equilibrium condensation behavior in engine exhaust. This invention provides an effective solution for engine turbine phase change flow testing and performance correction.

[0047] Fourth, for a long time, due to the complex internal flow conditions of turbines, significant pulsations in exhaust parameters, and the transient and invisible nature of the condensation process, it has been difficult to monitor and quantify water vapor condensation behavior without disrupting the flow field, and related effects are often simplified and ignored. This invention, by introducing in-situ optical droplet detection combined with thermodynamic model correction, achieves an effective solution to this problem for the first time at the turbine performance testing level. In the existing field of turbine performance testing, there is a prevalent technical bias that the exhaust working fluid can be approximated as a single gas phase, and that the impact of phase change on performance is negligible. This invention breaks through the above-mentioned inherent understanding, proving through experimental design and theoretical analysis that this assumption no longer holds under high water vapor conditions in engines, and that phase change monitoring and latent heat correction must be introduced to obtain reliable test results. Attached Figure Description

[0048] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this disclosure and, together with the description, serve to explain the principles of this disclosure;

[0049] Figure 1 This is a schematic diagram of the engine turbocharger system performance testing platform provided in an embodiment of the present invention;

[0050] Figure 2 This is a flowchart of the engine turbocharger system performance testing method provided in the embodiments of the present invention;

[0051] Figure 3 This is a schematic diagram of the performance testing method for an engine turbocharger system provided in an embodiment of the present invention;

[0052] In the diagram: 1. Hydrogen engine; 11. Air; 111. Air compressor; 112. Filter; 113. Temperature control box; 2. High-pressure hydrogen cylinder group; 21. Pressure reducing valve; 22. Mass flow meter; 23. Flame arrester; 24. Hydrogen injection rail; 3. Intake conditioning device; 4. Turbine; 41. Inlet flow channel; 42. Outlet flow channel; 421. Exhaust condenser; 422. Exhaust analyzer; 423. Exhaust pipe; 5. Compressor; 51. Inlet; 52. Air... 53. Air filter; 54. Electrically controlled back pressure valve; 55. Silencer; 6. Atmosphere; 7. Dynamic sensor group; 811. Inlet temperature sensor; 912. Inlet pressure sensor; 10. Outlet temperature sensor; 112. Outlet pressure sensor; 123. Outlet pressure sensor; 14. Photoelectric receiver; 15. Optical observation window; 16. Laser emitter; 17. Main control computer; 18. Data acquisition unit; 19. Variable volume pressure stabilizing chamber; 10. Steam; 101. Humidifier; 102. Pressure stabilizing box. Detailed Implementation

[0053] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of the present invention. However, the present invention can be practiced in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0054] The innovation of this invention lies in the fact that, for the first time, the latent heat of vaporization released by water vapor condensation is introduced into the energy conservation equation during the testing process. By introducing a latent heat correction term into the enthalpy balance, the system performance calculation deviation caused by simply treating wet gas as dry gas in existing testing methods is effectively avoided, thus improving the accuracy of the turbine 4 power and efficiency test results from both theoretical and engineering perspectives.

[0055] Example 1. As... Figure 1 As shown, the engine turbocharger system performance testing platform provided in this embodiment of the invention includes: a hydrogen engine 1 and an intake air conditioning device 3. The intake air conditioning device 3 includes an air compressor 111, a filter 112, a temperature control box 113, a humidifier 101, and a pressure stabilizing box 102 connected in sequence. Air 11 passes through the air compressor 111, the filter 112, and the temperature control box 113. The air, whose temperature is controlled by the temperature control box 113, enters the humidifier 101 with added steam 10. The humidified steam enters the pressure stabilizing box 102 and is input into the hydrogen engine 1.

[0056] Meanwhile, the high-pressure hydrogen cylinder group 2 delivers high-pressure hydrogen into the hydrogen engine 1 through the pressure reducing valve 21, mass flow meter 22, flame arrester 23, and hydrogen injection rail 24.

[0057] The hydrogen mixture in the hydrogen engine 1 enters the turbine 4 through the inlet channel 41 and the variable volume pressure stabilizing chamber 9;

[0058] The inlet of the inlet flow channel 41 is respectively equipped with an inlet temperature sensor 611 and an inlet pressure sensor 6 of the dynamic sensor group 6 of the flow channel;

[0059] The hydrogen combustion exhaust gas after turbine 4 combustion passes sequentially through outlet flow channel 42, exhaust condenser 421, exhaust analyzer 422, and exhaust pipe 423;

[0060] The outlet flow channel 42 is equipped with an outlet temperature sensor 621 and an outlet pressure sensor 622 installed in the dynamic sensor group 6.

[0061] An optical droplet detection device is installed near the impeller in the outlet flow channel 42. The optical droplet detection device includes a photoelectric receiver 7, an optical observation window 71, and a laser emitter 72.

[0062] An optical observation window 71 is opened at the outlet flow channel 42 near the impeller of the turbine 4. A laser emitter 72 is installed at the optical observation window 71, and the laser emitter 72 is connected to the photoelectric receiver 7.

[0063] For example, the temperature and pressure information detected by the imported temperature sensor 611 and the imported pressure sensor 612 are sent to the data acquisition unit 81;

[0064] The temperature and pressure information detected by the outlet temperature sensor 621 and the outlet pressure sensor 622 is transmitted to the data acquisition unit 81.

[0065] The photoelectric receiver 7 sends the detected optical droplet information to the data acquisition unit 81; the data acquisition unit 81 sends all the acquired data information to the main control computer 8;

[0066] Air is fed into compressor 5 through air filter 52 and air inlet 51. Compressor 5 further feeds air into turbine 4 to mix with hydrogen mixture. Turbine 4 further combusts the hydrogen mixture. Then, exhaust gas passes through compressor 5, electronically controlled back pressure valve 53, and silencer 54 to discharge atmospheric air 55.

[0067] Example 2, as Figure 2 As shown, the engine turbocharger system performance testing method provided in this embodiment of the invention relies on a test platform including a hydrogen engine 1, an intake conditioning device 3, a turbocharger assembly, a multi-physics field condensation monitoring system, and a main control computer 8.

[0068] The method includes the following steps:

[0069] S1. Test Environment Construction: The test platform is built. The exhaust manifold of the hydrogen engine 1 is connected to the inlet channel 41 of the turbine 4 via an insulated pipe. An inlet temperature sensor 611 and an inlet pressure sensor 612 are respectively arranged on the inlet channel 41 of the turbine 4. An outlet temperature sensor 621 and an outlet pressure sensor 622 are respectively arranged on the outlet channel 42. The inlet temperature sensor 611, inlet pressure sensor 612, outlet temperature sensor 621, and outlet pressure sensor 622 form a dynamic sensor group 6. The dynamic sensor group 6 can use piezoelectric sensors and thermocouples to capture the transient characteristics of pulsating exhaust. At the same time, an optical droplet detection device is installed near the impeller in the outlet channel 42.

[0070] In this embodiment, the experimental platform employs either laser extinction or a phase Doppler particle analyzer. Its working principle is as follows: a laser beam passes through the exhaust flow field; when condensed droplets are present in the flow field, the light intensity attenuates or generates a scattering signal, thereby inverting the Sauter mean diameter (SMD) and liquid water content (LWC) of the droplets.

[0071] S2, working fluid synthesis and conditioning, controls the hydrogen supply, and independently adjusts the air temperature and humidity entering the hydrogen engine 1 through the air conditioning device 3, driving the hydrogen engine 1 to run, and generating hydrogen exhaust working fluid with target fuel-air ratio and water vapor mole fraction at the inlet flow channel 41.

[0072] S3, Phase change flow field monitoring, during the expansion and power-making process of turbine 4, synchronously collect dynamic pressure and temperature data of inlet flow channel 41 and outlet flow channel 42, and use optical droplet detection device to obtain droplet light scattering signal or particle size distribution data in the exhaust of outlet flow channel 42.

[0073] S4, Data Correction and Calculation: The main control computer 8 calls the preset actual gas state model of hydrogen combustion products. Based on the collected pressure and temperature data of the turbine 4 inlet and outlet, combined with the droplet light scattering signal or particle size distribution data, it determines whether non-equilibrium condensation occurs in the exhaust gas during the expansion process of the turbine 4. Based on the latent heat of phase change of the condensed water vapor, it corrects and calculates the gas density, effective specific heat, mass flow rate, polytropic efficiency, and characteristic flow velocity parameters in the turbine 4 channel.

[0074] S5, Risk Assessment: Based on the acquired droplet light scattering signal or particle size distribution data, and the corrected calculated turbine outlet average flow velocity, blade relative inflow velocity, or local characteristic flow velocity parameters, combined with droplet size and relative impact velocity, the water erosion risk level of the turbine blade surface is assessed.

[0075] S6, by adjusting the volume of the variable volume pressure stabilizing chamber 9 on the turbine inlet flow channel 41, switches between steady-state flow test mode and pulsating flow test mode to compare the starting position of condensation shock wave under different pulsating frequencies.

[0076] For example, in step S2, the controlled water vapor mole fraction ranges from 15% to 35% to cover the full operating range of the hydrogen engine 1 from lean combustion to stoichiometric combustion.

[0077] For example, in step S2, the working fluid is synthesized and conditioned, and the intake air conditioning device 3 is started; the intake air conditioning device 3 includes an air compressor 111, a filter 112, a temperature control box 113, a humidifier 101, and a pressure stabilizing box 102; unlike the prior art which only adjusts the engine load to change the exhaust state, this method actively controls the relative humidity of the incoming air, for example, adjusting it to a certain level. With the temperature and the injection rate of high-pressure hydrogen cylinder group 2, the molar fraction of water vapor generated after combustion can be precisely controlled. The exhaust gas from hydrogen combustion.

[0078] Principle explanation: The chemical formula for hydrogen combustion is... By controlling the humidity of the incoming air and the air-fuel ratio It can accurately simulate the exhaust gas composition under different operating conditions, providing a stable working fluid basis for studying condensation phenomena.

[0079] For example, in step S3, phase change flow field monitoring is performed, and the hydrogen engine 1 is operated, with the high-temperature, high-humidity exhaust driving the turbine 4 to rotate at high speed. At this time, the data acquisition unit 81 simultaneously records the P and T data at the inlet and outlet. Simultaneously, the optical droplet detection device is activated. Within the nozzle ring and impeller of the turbine 4, the airflow accelerates and expands, the Mach number increases, and the static temperature drops sharply. According to classical nucleation theory, when the airflow temperature is below the dew point and the supercooling... More than about At that time, the airflow reaches the Wilson Point, where explosive homogeneous nucleation occurs.

[0080] At this point, the optical droplet detection device will detect a significant light scattering signal and record the start time of droplet formation and the particle size distribution.

[0081] In step S3, the optical droplet detection device uses light scattering or laser Doppler technology, and the monitoring indicators include the droplet Sauter mean diameter (SMD) and liquid water content (LWC).

[0082] For example, in step S4, the actual gas state model adopts the IAPWS-95 standard to calculate the true enthalpy and entropy values ​​of the humid mixed gas, replacing the ideal gas state equation.

[0083] The correction logic in step S4 is as follows: if the static temperature at the outlet is detected to rise and the optical droplet detection device detects a droplet signal, the system calculates the latent heat release of the phase change through the energy conservation equation, and subtracts the false temperature rise caused by the latent heat from the total enthalpy at the outlet, thereby obtaining the true enthalpy drop of the gas flow expansion work.

[0084] For example, in step S4, data correction and calculation: after receiving the data from S3, the main control computer 8 executes the core correction algorithm. Because the exhaust contains a large amount of water vapor, the ideal gas law can no longer be used. This system incorporates a Hyland-Wexler real gas model. The correction logic is as follows:

[0085] S401, Determine condensation: If the optical signal indicates the presence of droplets, and the outlet measurement temperature... It is higher than the theoretical adiabatic expansion temperature.

[0086] S402, Latent heat deduction: When water vapor condenses into droplets, it releases latent heat of vaporization. This heat is reabsorbed into the airflow, causing the measured temperature to be artificially high, creating a false impression of thermal throttling. According to the energy conservation equation, the system has:

[0087]

[0088] In the formula, The specific enthalpy per unit mass of the hydrogen combustion exhaust gas working fluid at the turbine inlet. This refers to the specific enthalpy per unit mass of the uncondensed gas phase component at the turbine outlet. For the droplet humidity fraction, This refers to the effective work done per unit mass of the turbine during its actual expansion process.

[0089] The equivalent dry gas temperature without latent heat heating is calculated, and the true enthalpy drop is determined. ;

[0090] S403, efficiency correction, calculates the variable efficiency of the turbine based on the actual enthalpy drop, eliminating efficiency calculation errors caused by latent heat of phase change. The error is typically significant. .

[0091] For example, in the risk assessment in step S5, the system calculates the average droplet size based on the acquired droplet size distribution data. Magnitude (usually in) to (order of magnitude) and the calculated average outlet velocity The Weber number of a droplet is calculated using the following expression:

[0092]

[0093] In the formula, For droplet density, Surface tension;

[0094] The system then outputs a water erosion risk level report based on this information. If... Exceeding the critical value indicates that the droplet impact intensity is sufficient to cause fatigue erosion of the blades, and the system will issue an alarm, prompting designers to optimize the impeller profile or control the exhaust temperature. This invention represents a leap from macroscopic thermodynamic parameter measurement to microscopic phase change fluid dynamics monitoring, providing a precise testing method for the development of a dedicated turbocharger for hydrogen engines.

[0095] For example, Figure 3 This is the principle of the engine turbocharger system performance testing method provided in the embodiments of the present invention.

[0096] As demonstrated by the above embodiments, this invention independently controls the temperature and humidity of the incoming air through intake conditioning, generating high-humidity pulsating exhaust with a specific water vapor molar fraction at the exhaust end; it utilizes an optical detection device installed at the turbine outlet to detect non-equilibrium condensate droplets in real time; and it corrects the collected thermodynamic parameters based on the actual gas state equation and a non-equilibrium phase change model, deducting efficiency losses caused by thermal throttling effects. This method solves the problem of existing tests neglecting the high humidity and phase change characteristics of hydrogen engine exhaust, and can accurately assess the true turbine efficiency and water erosion risk under wet steam conditions.

[0097] The embodiments of this invention have achieved positive technical results during research and development and practical application. By introducing a phase change flow field monitoring and thermodynamic parameter correction mechanism into the turbine performance testing process, this invention can effectively identify the non-equilibrium condensation phenomenon caused by high water vapor content in the exhaust gas of a hydrogen-fired engine turbine, and correct the resulting latent heat release and changes in flow characteristics. Compared with existing turbine performance testing methods that assume the exhaust working fluid is always in a single gas phase state, this invention has higher physical consistency and accuracy in the calculation results of key performance parameters such as turbine variable efficiency, mass flow rate, and characteristic flow velocity. On this basis, this invention further couples and analyzes phase change characteristic parameters such as droplet size distribution and liquid water content with the corrected flow field velocity information, so that the testing method can not only reflect the aerodynamic and thermodynamic performance of the turbine, but also assess the risk of water erosion caused by droplets to the turbine blades, thereby significantly expanding the functional dimensions of turbine performance testing. Theoretical analysis shows that ignoring the latent heat of phase change released by water vapor condensation will lead to systematic deviations in the enthalpy and performance parameters of the turbine outlet gas. This invention effectively avoids the accumulation of the above errors by introducing an actual gas state model and a latent heat correction term, making the test results closer to the actual operating state of the turbine under hydrogen combustion conditions.

[0098] Furthermore, by actively adjusting the composition of the experimental working fluid and the exhaust state, and switching between steady-state flow and pulsating flow test modes, this invention can reproduce the turbine operating state under different water vapor contents and pulsation frequencies under controllable conditions. This provides a more comprehensive and reliable experimental basis for the performance evaluation, structural optimization, and reliability analysis of hydrogen-fired engine turbocharging systems. Analysis combined with specific experimental or simulation results shows that the turbine performance parameter variation trends obtained by the method of this invention under the same operating conditions exhibit good consistency with the droplet generation region and particle size distribution characteristics, further verifying the technical advantages of this method in hydrogen-fired engine turbine performance testing and risk assessment.

[0099] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications, equivalent substitutions and improvements made by those skilled in the art within the scope of the technology disclosed in the present invention and within the spirit and principles of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A method for testing the performance of an engine turbocharger system, characterized in that, This method addresses the non-equilibrium condensation phenomenon caused by high water vapor content in engine turbine exhaust. It achieves high-precision testing of turbine performance parameters and blade water erosion risk assessment through in-situ monitoring of the phase change flow field coupled with thermodynamic performance correction. Specifically... Includes the following steps: S1, Experimental environment setup, construction of the experimental platform; S2, working fluid synthesis and conditioning, control the fuel supply, and independently adjust the air temperature and humidity entering the hydrogen engine (1) through the air conditioning device (3) to drive the hydrogen engine (1) to run, and generate hydrogen exhaust working fluid with target fuel-air ratio and water vapor mole fraction at the inlet flow channel (41) of the turbine (4). S3, Phase change flow field monitoring, during the turbine expansion and work process, the dynamic pressure and temperature data of the inlet flow channel (41) and outlet flow channel (42) of the turbine (4) are collected simultaneously, and the light scattering signal or particle size distribution data of the droplets in the exhaust of the outlet flow channel (42) are obtained by using an optical droplet detection device. S4, Data Correction and Calculation: The main control computer (8) calls the preset actual gas state model of hydrogen combustion products. Based on the dynamic pressure and temperature data of the turbine (4) inlet channel (41) and outlet channel (42) collected, combined with the droplet light scattering signal or particle size distribution data, it determines whether non-equilibrium condensation occurs in the exhaust gas during the expansion process of the turbine (4). Based on the latent heat release of the condensed water vapor, it corrects and calculates the gas density, effective specific heat, mass flow rate, polytropic efficiency and characteristic flow velocity parameters in the turbine channel of the turbine (4). S5, Risk assessment: Based on the obtained droplet light scattering signal or particle size distribution data, and the corrected calculation of the turbine (4) outlet average flow velocity, blade relative inflow velocity or local characteristic flow velocity parameters, combined with droplet particle size and relative impact velocity, assess the water erosion risk level of the turbine (4) blade surface.

2. The engine turbocharger system performance testing method according to claim 1, characterized in that, In step S2, the water vapor mole fraction is controlled to be in the range of 15%-35%.

3. The engine turbocharger system performance testing method according to claim 1, characterized in that, In step S3, the optical droplet detection device uses light scattering or laser Doppler technology, and the monitoring indicators include the droplet Sauter mean diameter (SMD) and the liquid water content (LWC).

4. The engine turbocharger system performance testing method according to claim 1, characterized in that, In step S4, the actual gas state model adopts the IAPWS-95 standard to calculate the true enthalpy and entropy values ​​of the moist mixed gas.

5. The engine turbocharger system performance testing method according to claim 1, characterized in that, In step S4, the correction and calculation are as follows: If an increase in the outlet static temperature is detected and the optical droplet detection device detects a droplet signal, the latent heat release of the phase change is calculated using the energy conservation equation. The false temperature rise caused by this latent heat is subtracted from the total enthalpy at the outlet to obtain the true enthalpy drop caused by the work done by the gas flow expansion. The specific steps are as follows: S401, Detect condensation: If the optical signal indicates the presence of droplets, and the outlet measured temperature... Higher than the theoretical adiabatic expansion temperature; S402, Latent heat deduction: When water vapor condenses into droplets, it releases latent heat of vaporization. According to the law of conservation of energy, we have: ； In the formula, The specific enthalpy per unit mass of the hydrogen combustion exhaust gas working fluid at the turbine inlet. This refers to the specific enthalpy per unit mass of the uncondensed gas phase component at the turbine outlet. For droplet humidity fraction, This refers to the effective work done per unit mass of the turbine during its actual expansion process. The equivalent dry gas temperature without latent heat heating is calculated, and the true enthalpy drop is determined. ; S403, efficiency correction, calculates the variable efficiency of the turbine based on the actual enthalpy drop, eliminating efficiency calculation errors caused by latent heat of phase change.

6. The engine turbocharger system performance testing method according to claim 1, characterized in that, In the risk assessment in step S5, the average droplet size D and the average outlet velocity are calculated based on the obtained droplet size distribution data. Calculate the Weber number of the droplet. The expression is: ； In the formula, For droplet density, Surface tension; Based on this, a water erosion risk level report is generated, if the Weber number... If the droplet impact intensity exceeds the critical value, it will cause fatigue erosion of the blade and trigger an alarm.

7. The engine turbocharger system performance testing method according to claim 1, characterized in that, After step S5, by adjusting the volume of the variable volume pressure stabilizing cavity (9) on the inlet flow channel (41), the test mode is switched between steady flow test mode and pulsating flow test mode to compare the starting position of condensation shock wave under different pulsating frequencies.

8. A performance testing platform for an engine turbocharging system, characterized in that, The platform implements the engine turbocharger system performance testing method as described in any one of claims 1-7, and the platform includes: The intake conditioning device (3) includes an air compressor (111), a filter (112), a temperature control box (113), a humidifier (101), and a pressure stabilizing box (102) connected in sequence. Air (11) passes through the air compressor (111), the filter (112), and the temperature control box (113). The air temperature controlled by the temperature control box (113) enters the humidifier (101) which adds steam (10). The humidified steam enters the pressure stabilizing box (102) and is input to the hydrogen engine (1). High-pressure hydrogen cylinder group (2), high-pressure hydrogen is sent into hydrogen engine (1) through pressure reducing valve (21), mass flow meter (22), flame arrester (23) and hydrogen injection rail (24) in sequence; The hydrogen mixture in the hydrogen engine (1) enters the turbine (4) through the inlet channel (41) and the variable volume pressure stabilizing chamber (9). The hydrogen combustion exhaust gas from the turbine (4) is discharged sequentially through the outlet channel (42), exhaust condenser (421), exhaust analyzer (422), and exhaust pipe (423); The dynamic sensor group (6) includes an inlet temperature sensor (611), an inlet pressure sensor (612), an outlet temperature sensor (621), and an outlet pressure sensor (622). The inlet temperature sensor (611) and the inlet pressure sensor (612) are installed on the inlet flow channel (41). The outlet flow channel (42) is equipped with the outlet temperature sensor (621) and the outlet pressure sensor (622). An optical droplet detection device is installed at the impeller of the turbine (4) near the outlet flow channel (42). The optical droplet detection device includes a photoelectric receiver (7), an optical observation window (71), and a laser emitter (72). The optical observation window (71) is located in the outlet flow channel (42) near the impeller of the turbine (4). A laser emitter (72) is installed in the optical observation window (71), and the laser emitter (72) is connected to the photoelectric receiver (7).

9. The engine turbocharging system performance testing platform according to claim 8, characterized in that, The temperature and pressure information detected by the imported temperature sensor (611) and the imported pressure sensor (612) is transmitted to the data acquisition unit (81). The temperature and pressure information detected by the outlet temperature sensor (621) and the outlet pressure sensor (622) are sent to the data acquisition unit (81). The photoelectric receiver (7) sends the detected optical droplet information to the data acquisition unit (81); the data acquisition unit (81) sends all the acquired data information to the main control computer (8).

10. The engine turbocharging system performance testing platform according to claim 8, characterized in that, Air (11) enters the compressor (5) through the air filter (52) and the air inlet (51), and after being compressed by the compressor (5), it is sent to the turbine (4) and mixed with the hydrogen mixture. The hydrogen mixture is burned in the turbine (4) to do work, and the exhaust gas generated flows through the electronically controlled back pressure valve (53) and the silencer (54) in sequence before being discharged into the atmosphere (55).

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