Environmental test box for simulating real fuel gas environment of aero-engine hot end component

Abstract

The invention discloses an environment test box for simulating a real fuel gas environment of a hot end component of an aero-engine, and belongs to the technical field of aero-engines. Comprising a gas supply unit; an inlet section of the mixing chamber is connected with the fuel gas supply unit, and the mixing chamber is used for receiving and mixing various fuel gas components according to a preset proportion; the experiment box is connected with the outlet section of the mixing chamber and is used for accommodating a test piece and carrying out a mechanical property test; a vacuum system; the intelligent control system comprises a PLC (Programmable Logic Controller); and the cooling and exhausting device is used for cooling the high-temperature mixed fuel gas after the experiment and then exhausting the high-temperature mixed fuel gas. Through combination of vacuum pretreatment, a structured mixing chamber and intelligent PLC control based on a pulsation-mixing correlation model, high-precision simulation of the real gas environment of the aero-engine hot end component is realized.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aero-engines, and particularly relates to an environment test box for simulating a real fuel gas environment of a hot end component of an aero-engine. BACKGROUND

[0002] The hot end component of an aero-engine is the part with the highest temperature and the most severe working environment inside the aero-engine. These components bear extreme high temperature, high pressure, strong airflow and high-speed wear, and the reliability and safety thereof directly affect the performance and service life of the engine.

[0003] With the continuous development of ceramic matrix composites (CMC), the CMCs are currently applied to many hot end components of aero-engines, such as turbine blade leading edges, flame tubes and tail nozzles, due to their high-temperature resistance, low density and corrosion resistance. It is urgent to build a mechanical test platform for testing the hot end components of aero-engines with new materials.

[0004] Currently, the environment simulation and mechanical test for the hot end components mainly have the following technical bottlenecks: Environmental simulation distortion: The widely used "high-temperature water-oxygen environment" simulation method simplifies the fuel gas components too much, ignores the thermal physical and chemical effects of key components such as nitrogen and carbon dioxide, and causes significant deviation between the experimental environment and the complex fuel gas atmosphere of the real service of the component, so that the engineering guidance value of the test data is limited.

[0005] Inhomogeneous fuel gas mixing: When trying to simulate multi-component fuel gas, the mixing means of the existing technology is often rough, and the uniformity of the mixed gas is insufficient before entering the experimental box. This leads to uneven distribution of the fuel gas components, temperature and heat flux density acting on the surface of the test piece, introduces an experimental error that cannot be ignored, and makes it difficult to truly reflect the overall performance of the component.

[0006] System control lag and interference: The existing experimental systems generally lack real-time and effective monitoring of the quality of the mixing process. Usually, post-sampling analysis or indirect control based on a single parameter (such as temperature) is used, which cannot achieve online evaluation and active control of the mixing quality of the fuel gas. At the same time, the residual air in the experimental cavity can pollute the simulated fuel gas environment, and the method of relying on protective gas such as argon to isolate air can itself change the local environment around the test piece and interfere with the real corrosion and oxidation process.

[0007] Safety and cost problems: Some experimental devices generate high-temperature fuel gas by directly burning fuel. This method not only has safety risks, but also has high experimental costs, complex operation and difficulty in long-term and high-repetitive mechanical performance testing.

[0008] Therefore, it is urgent to develop an environment test box for simulating the real gas environment of the hot end part of an aero-engine to test the real mechanical properties of the hot end part of the aero-engine and high-temperature alloy materials. SUMMARY

[0009] Technical problems to be solved: In order to avoid the shortcomings of the prior art, the present application provides an environment test box for simulating the real gas environment of the hot end part of an aero-engine, which mixes different components of the gas in different proportions and in different orders according to different gas rates into a mixing chamber through a gas tank and a water vapor generator, and then passes the mixed gas into a vacuum test box containing a test piece, and then controls the gas inlet and valve switching through a PLC controller, so as to simulate the real gas environment of the hot end part of the aero-engine, and test the mechanical properties of the test piece in the test box. The present application realizes high-precision simulation of the real gas environment of the hot end part of the aero-engine by combining "vacuum pretreatment-structured mixing chamber-intelligent PLC control based on pulsation-mixing correlation model".

[0010] The technical solution of the present application is: an environment test box for simulating the real gas environment of the hot end part of an aero-engine, comprising: A gas supply unit comprising a plurality of independent gas tanks for providing nitrogen, carbon dioxide and oxygen, and a water vapor generator for independently generating water vapor; A mixing chamber connected to the gas supply unit at the inlet section, for receiving and mixing a plurality of gas components in a predetermined proportion; the mixing chamber is internally provided with a cyclone and a circular arc shell structure for multiple backflushing and shearing mixing of the incoming gas; A test box connected to the outlet section of the mixing chamber for accommodating the test piece and testing the mechanical properties; A vacuum system for vacuumizing the mixing chamber and the test box before the experiment to exclude the interference of internal air; An intelligent control system comprising a PLC controller; the PLC controller dynamically adjusts the output of the gas supply unit by real-time monitoring of the fluid state parameters at the outlet of the mixing chamber, and controls the on-off of the mixed gas to the test box; A cooling exhaust device for cooling and exhausting the high-temperature mixed gas after the experiment. The further technical solution of the present application is: the mixing chamber comprises from bottom to top: An inlet section provided with independent pipe interfaces for nitrogen to flow in from the side pipe and water vapor, carbon dioxide and oxygen to flow in from the lower pipe; A mixing section which is a middle cylinder with the circular arc shell arranged inside for backflushing of the gas flow to realize secondary mixing; The converging section is in a circular truncated cone structure, and is used for increasing the flow speed of the gas and strengthening the mixing effect; The outlet section is provided with a cyclone, and is used for guiding the uniformly mixed gas into the test box. A further technical scheme of the present application is that the blade inclination angle of the cyclone is 10°, the distance between the circular arc shell and the position of the inlet of the mixing chamber is 35 mm, and the semi-major axis of the circular arc shell is 30 mm; and after the gas is mixed in the mixing chamber, the mixing degree distribution coefficient of the gas reaches .

[0011] A further technical scheme of the present application is that the pipeline connecting the water vapor generator and the mixing chamber is a heat tracing pipeline, and the heat tracing pipeline is configured to maintain the temperature in the pipeline within an allowable error range of 110℃, so as to prevent the water vapor from condensing.

[0012] A further technical scheme of the present application is that the PLC controller comprises: A sensor module is configured to collect the pressure time sequence signal of the outlet of the mixing chamber in real time at a sampling frequency of not less than 10 kHz; An analog input module is configured to preset a target mixing degree distribution coefficient; An industrial control computer is configured to run a pulsation-mixing correlation model, and calculate the current mixing degree distribution coefficient in real time according to the collected pressure data; A valve control module is configured to dynamically adjust the flow of each component in the gas supply unit when the current mixing degree distribution coefficient does not reach the target mixing degree distribution coefficient; A switch parameter module is configured to open the valve between the mixing chamber and the test box and start the heating and mechanical testing device of the test box when the current mixing degree distribution coefficient does not reach the target mixing degree distribution coefficient. A further technical scheme of the present application is that the mathematical expression of the pulsation-mixing correlation model is:

[0013] wherein, represents the mixing degree distribution coefficient after a certain period of time; represents a system characteristic constant; represents the standard deviation of the pressure sampling; a is an exponential factor; represents the average pressure in a time period.

[0014] A method for simulating a real gas environment using the environmental test box, comprising the following steps: Preprocessing: starting the vacuum system, and evacuating the air in the mixing chamber and the test box; Gas supply: starting the water vapor generator and the gas tank, and delivering the gas to the mixing chamber according to the preset proportion of each component; Blending and monitoring: the gas is blended multiple times in the blending chamber, while the PLC controller monitors the fluid state at the outlet of the blending chamber in real time and evaluates the blending uniformity accordingly; Feedback control: if the blending uniformity does not reach the preset target, the PLC controller dynamically adjusts the output parameters of the gas supply unit until the blending uniformity meets the standard; Experimental execution: when the blending uniformity meets the standard, the PLC controller opens the valve from the blending chamber to the experimental box, passes the mixed gas into the experimental box, and starts the heating and mechanical property test.

[0015] A further technical solution of the present application is that in the blending and monitoring, the PLC controller acquires the single-point pressure time series signal at the outlet of the blending chamber in real time, and substitutes it into the pulsation-blending correlation model to calculate the current blending degree distribution coefficient, which is used as an evaluation index of the blending uniformity. A further technical solution of the present application is that in the pulsation-blending correlation model, the system characteristic constant η is determined as 1.0-1.2 through preliminary experiments and fluid simulation, and the exponential factor a is determined as 1.5-2.0.

[0016] A further technical solution of the present application is that in the gas supply, the volume fraction ratio of the gas components passed in is: nitrogen 70%-80%, oxygen 10%-20%, carbon dioxide about 5%, and water vapor about 5%.

[0017] Beneficial effects The beneficial effects of the present application are: 1) The present application uses a vacuum pump to evacuate the air in the blending chamber and the experimental box, eliminating the influence of the original air in the experimental box on the experiment, and can simulate the real gas environment of the hot end part of an aero-engine.

[0018] 2) The multi-stage blending chamber designed in the present application has a "cyclone-circular-arc shell-converging section", which realizes rapid and sufficient mixing of the gas on a microscale through a three-time blending mechanism of preliminary blending by cyclone, secondary blending by circular-arc shell backflushing, and accelerated and intensified blending by converging section, and can ensure that the mixed gas is uniformly passed into the experimental box.

[0019] 3) The present application simulates the environment after fuel combustion by passing in gas, and the combination of the multi-component working gas tank and the water vapor generator can accurately configure and pass in multi-component gas containing nitrogen, carbon dioxide, oxygen and water vapor, breaking through the limitations of traditional "high-temperature water-oxygen environment" or single gas simulation, and for the first time, the real service gas atmosphere of the hot end part is reproduced with high fidelity under laboratory conditions. And there is no direct fuel combustion experiment, which saves resources and reduces the danger of the experiment.

[0020] 4) The PLC controller of this invention transforms the key indicator of "mixing uniformity," which is difficult to measure directly and in real time, into a "single-point pressure pulsation" signal that can be acquired at high frequency for online, indirect, and accurate evaluation by running a pulsation-mixing correlation model. This method bypasses the complex and expensive direct density measurement system, significantly reducing system complexity and cost while ensuring accuracy. Based on this evaluation result, closed-loop feedback control can dynamically adjust the gas flow rate, ensuring that each experiment can automatically reach and maintain the preset optimal mixing state. This achieves a leap from "extensive open-loop" to "precise closed-loop" environmental simulation, ensuring the consistency and repeatability of experimental results. Attached Figure Description Figure 1 This is a schematic diagram of an environmental test chamber simulating the real gas combustion environment of aero-engine hot-end components, as described in an embodiment of the present invention. Figure 2 This is a topographical diagram of the mixed exterior in an embodiment of the present invention; Figure 3 This is a cross-sectional view of the mixing chamber in an embodiment of the present invention; Figure 4 This is an axial view of the cyclone separator in the mixing chamber of this invention. Figure 5 This is a control law framework diagram of the PLC controller in an embodiment of the present invention.

[0021] Explanation of reference numerals in the attached drawings: 10. Steam generator; 20. Gas pipe; 30. Heat tracing pipe; 40. Mixing chamber; 41. Nitrogen inlet pipe; 42. Cyclone separator; 43. Arc shell; 44. Converging section; 45. Rounded corner shell; 46. Carbon dioxide and oxygen inlet pipes and heat tracing pipes; 50. Valve; 60. Test chamber; 70. High-temperature resistant fixture; 80. Test piece; 90. Cooling and exhaust device. Detailed Implementation

[0022] The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the invention, and should not be construed as limiting the invention.

[0023] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," and "counterclockwise," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0024] Currently, the core function of hot-end components in aero-engines is to compress air, mix it with fuel, combust it, and generate a high-temperature gas flow to provide power. Therefore, mechanical tests on hot-end components of aero-engines should simulate the actual combustion environment during operation to obtain the most accurate experimental data and results. However, due to limitations in experimental setups and equipment, since the required temperature for hot-end components exceeds 1500℃, argon gas-protected fixtures are necessary during mechanical tests, which significantly affects the accuracy of the experiments. Furthermore, most experiments use a high-temperature water-oxygen environment to simulate the combustion environment, but this method ignores the influence of other combustion components. Even the few experiments that simulate the actual combustion environment still have many problems, such as incomplete preheating or uncontrollable temperature leading to experimental errors, inability to uniformly mix the combustion gases, and inability to eliminate the influence of the original air in the test chamber on the test specimen.

[0025] To address the above problems, this invention provides an environmental test chamber that simulates the real combustion environment of hot-end components of an aero-engine, comprising: The gas supply unit includes multiple independent gas tanks for supplying nitrogen, carbon dioxide, and oxygen, as well as a steam generator for independently generating water vapor. The mixing chamber, whose inlet section is connected to the gas supply unit, is used to receive and mix multiple gas components in a preset ratio; the mixing chamber is equipped with a cyclone separator and an arc shell structure for multiple backflushing and shearing mixing of the incoming gas flow. The test chamber, connected to the outlet section of the mixing chamber, is used to contain the test specimens and perform mechanical property tests. A vacuum system is used to evacuate the mixing chamber and experimental box before the experiment to eliminate interference from internal air. The intelligent control system includes a PLC controller; the PLC controller dynamically adjusts the output of the gas supply unit and controls the flow of mixed gas to the experimental chamber by real-time monitoring of the fluid state parameters at the outlet of the mixing chamber; The cooling exhaust device is used to cool down the high-temperature mixed gas after the experiment before releasing it. Preferably, the mixing chamber comprises, from bottom to top: The inlet section is equipped with an independent pipe interface, allowing nitrogen to flow in from the side pipe, while water vapor, carbon dioxide, and oxygen flow in from the bottom pipe. The mixing section is a central cylinder with an arc shell inside, which is used to backflush the incoming gas flow to achieve secondary mixing. The converging section, with its frustum-shaped structure, is used to increase the gas flow rate and enhance the mixing effect. The outlet section is equipped with a cyclone separator to guide the uniformly mixed gas into the experimental chamber. Preferably, the PLC controller includes: A sensor module is used to acquire the pressure timing signal at the outlet of the mixing chamber in real time at a sampling frequency of not less than 10 kHz; Analog input module, used to preset the target mixing degree distribution coefficient; An industrial control computer is used to run a pulse-mixing correlation model and calculate the current mixing degree distribution coefficient in real time based on the collected pressure data. The valve control module is used to dynamically adjust the flow rate of each component in the gas supply unit when the current mixing degree distribution coefficient has not reached the target mixing degree distribution coefficient; The switch parameter module is used to open the valve from the mixing chamber to the experimental chamber and start the heating and mechanical testing device of the experimental chamber when the current mixing degree distribution coefficient has not reached the target mixing degree distribution coefficient. Preferably, the mathematical expression of the pulsation-mixing correlation model is as follows:

[0026] in, This represents the mixing degree distribution coefficient after a certain testing period; Represents the system characteristic constants; Indicates the standard deviation of pressure sampling; a It is an exponential factor; This indicates the average pressure over a given time period.

[0027] The present invention also provides a method for simulating a real gas environment using the environmental test chamber, comprising the following steps: Pretreatment: Start the vacuum system to evacuate the air from the mixing chamber and the experimental chamber; Gas supply: Start the steam generator and gas tank, and supply gas to the mixing chamber according to the preset proportions of each component; Blending and monitoring: The gas is blended multiple times in the blending chamber, while the PLC controller monitors the fluid state at the outlet of the blending chamber in real time and evaluates the blending uniformity accordingly. Feedback control: If the mixing uniformity does not reach the preset target, the PLC controller dynamically adjusts the output parameters of the gas supply unit until the mixing uniformity meets the target. Experimental execution: Once the mixing uniformity meets the standard, the PLC controller opens the valve from the mixing chamber to the experimental chamber, introduces the mixed gas into the experimental chamber, and starts the heating and mechanical property testing.

[0028] Specifically, in the mixing and monitoring process, the PLC controller collects the single-point pressure time-series signal at the outlet of the mixing chamber in real time and substitutes it into the pulsation-mixing correlation model to calculate the current mixing degree distribution coefficient, which is used as an evaluation index of the mixing uniformity. The above technical solution will be further analyzed below with reference to the accompanying drawings and embodiments: In one embodiment, refer to Figure 1 As shown, this embodiment of an environmental test chamber simulating the real combustion environment of hot-end components of an aero-engine includes a gas tank, a steam generator, and a mixing chamber (see attached diagram). Figure 2 , 3 ), PLC controller, experimental box, cooling and exhaust device.

[0029] The gas supply unit consists of multiple independent liquefied gas tanks (containing nitrogen, carbon dioxide, and oxygen respectively) and an independent steam generator. The outlets of each gas tank and the steam generator are connected to the inlet of the mixing chamber via pipelines. These pipelines are equipped with PLC-controlled regulating valves to precisely control the flow rate of each gas supply line.

[0030] Specifically, the structure of a steam generator mainly includes a furnace, a water shell, a heat source, and a steam chamber. During operation, the steam generator uses the heat source in the furnace to heat the water in the water shell to produce steam.

[0031] Blending chamber: Its inlet is located at the bottom and is connected to the aforementioned gas supply unit via a pipeline. The interior of the blending chamber is the core mixing area, and its outlet is connected to the experimental chamber via a PLC-controlled valve.

[0032] Specifically, refer to Figure 2 and Figure 3 As shown, the mixing chamber is divided into an inlet section, a mixing section, a convergence section, and an outlet section from bottom to top. The inlet section, connected to the gas cylinder and steam generator, is located directly below the mixing chamber. Nitrogen flows in separately from a side pipe, while steam, carbon dioxide, and oxygen flow in from a bottom pipe. The mixing section is a central cylinder with an arc-shaped shell in the middle, its function being to allow the incoming gas flow to backflow and mix, improving the mixing effect. The convergence section is a frustum, its function being to increase the gas flow rate and mixing effect. The outlet, connected to a cyclone separator located above the mixing chamber, is used to guide the mixed gas into the experimental chamber.

[0033] Specifically, refer to Figure 4 As shown, a cyclone separator is connected to the inlet of the mixing chamber. Its structure mainly includes a shell, blades, and a central hole, and it is mainly used for preliminary mixing of fuel gases. Nitrogen enters the mixing chamber through the blades, while other fuel gases enter the mixing chamber through the central hole.

[0034] Specifically, the pipes connecting the steam generator and the mixing chamber use heat tracing pipes to ensure that the pipe temperature is around 110℃.

[0035] Experimental chamber: A semi-enclosed chamber with an observation window and mounting port for easy operation at the front. The chamber is equipped with high-temperature resistant clamps to secure the test specimens. The experimental chamber is connected to a cooling and exhaust system via piping.

[0036] Vacuum system: It is connected to the mixing chamber and the experimental chamber respectively through a vacuum pump and corresponding valves and pipes, and is used to evacuate the air inside both before the experiment begins.

[0037] Intelligent control system: The PLC controller serves as the core, and its sensor module monitors the pressure at the outlet of the mixing chamber in real time via a pressure sensor. Its output module is electrically connected to the regulating valve of the gas supply unit, the valve from the mixing chamber to the experimental chamber, the heater of the experimental chamber, and the vacuum pump and other actuators.

[0038] Preferably, refer to Figure 5 As shown, the PLC controller includes an industrial control computer (IPC) and the following functional modules: a sensor module that acquires the timing signal of the mixing chamber outlet pressure in real time at a sampling rate of 10 kHz. The data is then imported into the industrial control computer; the analog input module includes a preset target mixing degree distribution coefficient. Valve control module: dynamically adjusts gas / steam flow; Switch parameter module: controls the start and stop of heating and mechanical testing in the experimental chamber.

[0039] Cooling and exhaust device: Located at the end of the system, it is used to cool and treat the high-temperature mixed gas after the experiment is completed before venting it into the air.

[0040] The device operates as follows: The vacuum pump was turned on to evacuate the air from the mixing chamber and experimental box, eliminating the influence of air on the simulated real gas combustion environment. Then, the steam generator and gas cylinder were turned on to deliver gas at the input rate set according to the proportions of various gas components. According to the investigation, the gas composition produced by fuel combustion is as follows: nitrogen accounts for 70% to 80%, oxygen for 10% to 20%, carbon dioxide for approximately 5%, and water vapor for approximately 5%. Other gases such as hydrogen and carbon monoxide are toxic gases with a volume fraction of less than 0.01%, and are not considered for experimental safety and simplicity.

[0041] Preliminary mixing: Nitrogen enters through side intake pipe 1 in the inlet section, while the remaining fuel gas, carbon dioxide, oxygen, and water vapor enter through intake pipe 6 below and the heating pipe; in the mixing section, carbon dioxide, oxygen, and water vapor enter through the central hole of hydrocyclone 2; since nitrogen has the largest proportion in the fuel gas, its axial motion is converted into rotational motion by the blades of hydrocyclone 2 in the inlet section, and centrifugal force is used to form a backflow, thereby initially mixing nitrogen with the remaining fuel gas.

[0042] Backflush mixing: The inlet of the mixing section has a rounded shell to facilitate secondary mixing of the gas. There is an arc shell in the middle. The gas in the middle part diffuses to the surrounding gas through the arc shell using the backflush force and mixes with the surrounding gas for the third time. Converging mixing: The pipe diameter decreases in the fourth convergence section, further improving the mixing effect and rate of the mixed gas.

[0043] To characterize the mixing effect of the mixing chamber, the following parameters are defined:

[0044] in, The mixing degree distribution coefficient represents the deviation between the maximum density and the average density of the mixed gas at a certain cross section. The smaller the value, the better the mixing effect of the gas. For a certain cross-section, the maximum density The average density is given on a certain cross section.

[0045] Preferably, the blade angle of the cyclone separator in the mixing chamber is... The export blending distribution coefficient is Compare the blade angles. Mixing distribution coefficient and blade angle Mixing distribution coefficient Minimum.

[0046] Preferably, the distance between the arc-shaped shell of the mixing chamber and the inlet position is... The export blending distribution coefficient is .contrast Mixing distribution coefficient and Mixing distribution coefficient Minimum.

[0047] Preferably, the semi-major axis of the arc-shaped shell of the mixing chamber is The export blending distribution coefficient is .contrast Mixing distribution coefficient and Mixing distribution coefficient Minimum. (The above data comes from multiple sets of simulation and experimental data and is representative to a certain extent.) Experiments and ANSYS Fluent fluid analysis showed that the mixing distribution coefficient at the gas inlet was [value missing]. The minimum mixing distribution coefficient at the outlet is Improved blending effect The first mixing occurs at the hydrocyclone, and the mixing degree distribution coefficient is from [number missing]. Become Improved blending effect The second blending was a circular arc shell recoil blending, with the blending degree distribution coefficient from [number missing] times; Become Improved blending effect The third mixing step is the convergence segment, and the mixing degree distribution coefficient changes from [number missing] times; Become Improved blending effect The analysis confirmed that the mixing chamber achieved the goal of uniformly delivering the mixed gas to the experimental chamber.

[0048] In one embodiment, the industrial control computer (IPC) runs a pulsation-mixing correlation model based on single-point pressure time-series data. This model calculates the relative standard deviation of pressure in real time and establishes a power-law relationship between it and the mixing degree distribution coefficient. This significantly simplifies the sensing system structure while ensuring evaluation accuracy (if the outlet temperature of the mixing chamber changes very little, the density pulsation mainly originates from pressure pulsation). The specific implementation steps are as follows: Step 1: Initialization and Preset. In the analog input module of the PLC controller, set the target mixing degree distribution coefficient required for this experiment. (For example, 0.01).

[0049] Step 2: Data Acquisition. After starting the gas supply unit, the sensor module acquires the single-point pressure timing signal at the outlet of the mixing chamber in real time at a high frequency of 10 kHz.

[0050] Step 3: Condition Assessment. The collected pressure data is transmitted in real time to the industrial control computer (IPC). The pulsation-mixing correlation model is as follows:

[0051] in, —The mixing degree distribution coefficient after a certain period of time was tested. —System characteristic constants (determined to be 1.0-1.2 based on experimental simulation) —Standard deviation of pressure sampling (reflecting pulsation intensity)

[0052] —Average pressure over a period of time

[0053] —Exponential factor (determined to be 1.5-2.0 through experimental simulation).

[0054] This model transforms density uniformity, which is difficult to measure directly, into pressure pulsation, an index that is easy to calculate.

[0055] Step 4: Feedback and Adjustment. IPC will calculate the real-time miscibility distribution coefficient. With the preset target Compare them.

[0056] like > If the mixing is uneven, the valve control module is triggered to dynamically fine-tune the outlet regulating valves of each gas tank and steam generator, changing the flow rate of the corresponding component until... Meets the standard.

[0057] Step 5: Execute the experiment. When the system determines... ≤ Once the system stabilizes, the switching parameter module of the PLC controller immediately activates: it opens the valve from the mixing chamber to the test chamber, simultaneously starts the heater in the test chamber to heat the mixed gas to the target temperature (e.g., 1500℃), and links with mechanical testing equipment such as DIC to begin measuring the performance of the test piece.

[0058] During the experiment, the gas and steam generators were kept running continuously, and excess high-temperature mixed gas entered the cooling and exhaust device for cooling and recycling.

[0059] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of the present invention without departing from the principles and spirit of the present invention.

Claims

1. An environmental test chamber simulating a real gas environment of a hot end component of an aeroengine, characterized in that, The application relates to a gas mixing device for testing the mechanical properties of a test piece, and belongs to the field of mechanical testing. The device comprises the following parts: a gas supply unit comprising multiple groups of independent gas tanks for supplying nitrogen, carbon dioxide and oxygen and a water vapor generator for independently generating water vapor; a mixing chamber connected with the gas supply unit at an inlet section for receiving and mixing multiple gas components in a preset proportion; the mixing chamber is internally provided with a cyclone and a circular-arc shell structure for multiple backflow and shearing mixing of the incoming gas flow; an experimental box connected with an outlet section of the mixing chamber for accommodating the test piece and performing mechanical property testing; a vacuum system for performing vacuumizing treatment on the mixing chamber and the experimental box before the experiment to remove the interference of internal air; an intelligent control system comprising a PLC controller; the PLC controller dynamically adjusts the output of the gas supply unit by real-time monitoring of the fluid state parameters at the outlet of the mixing chamber and controls the on-off of the mixed gas to the experimental box; 2. The environmental test chamber simulating the real gas environment of the hot end part of an aero-engine according to claim 1, characterized in that: a cooling and exhaust device for cooling and discharging the high-temperature mixed gas after the experiment. The mixing chamber comprises the following parts from bottom to top: an inlet section provided with independent pipeline interfaces for the nitrogen to flow in from the side pipeline and the water vapor, carbon dioxide and oxygen to flow in from the lower pipeline; a mixing section being a middle cylinder internally provided with the circular-arc shell for backflow of the gas flow to realize secondary mixing; a converging section being a circular truncated cone structure for increasing the gas flow rate and strengthening the mixing effect; 3. The environmental test chamber simulating the real gas environment of the hot end part of an aero-engine according to claim 1, characterized in that: The blade angle of the cyclone is 10°, the distance between the circular arc shell and the position of the mixing chamber inlet is 35mm, the semi-major axis of the circular arc shell is 30mm; and after mixing through the mixing chamber, the mixing degree distribution coefficient of the gas reaches .

4. The environmental test chamber simulating the real gas environment of the hot end part of an aero-engine according to claim 1, characterized in that: an outlet section provided with a cyclone for guiding the uniformly mixed gas into the experimental box.

5. The environmental test chamber simulating the real gas environment of the hot end part of an aero-engine according to claim 1, characterized in that: The pipeline connecting the water vapor generator with the mixing chamber is a heat tracing pipeline, which is configured to maintain the temperature in the pipeline within an allowable error range of 110 DEG C to prevent the water vapor from condensing. The PLC controller comprises the following parts: a sensor module for real-time acquisition of the pressure time sequence signal at the outlet of the mixing chamber at a sampling frequency of not less than 10 kHz; an analog input module for presetting a target mixing degree distribution coefficient; an industrial control computer for running a pulsation-mixing correlation model, calculating the current mixing degree distribution coefficient in real time according to the acquired pressure data; a valve control module for dynamically adjusting the flow of each component in the gas supply unit when the current mixing degree distribution coefficient does not reach the target mixing degree distribution coefficient; 6. The environmental test chamber that simulates a real gas environment of a hot end component of an aero-engine according to claim 5, characterized in that: a switch parameter module for opening the valve from the mixing chamber to the experimental box and starting the heating and mechanical testing device of the experimental box when the current mixing degree distribution coefficient does not reach the target mixing degree distribution coefficient. wherein, represents a blending degree distribution coefficient after a certain time of testing; represents a system characteristic constant; represents a standard deviation of pressure sampling; a is an exponential factor; represents an average pressure in a time period.

7. A method of simulating a real gas environment of a hot section component of an aeroengine using an environmental test chamber according to any one of claims 1 to 6, characterised in that, The mathematical expression of the pulsation-mixing correlation model is as follows: The device comprises the following steps: pretreatment: starting the vacuum system to evacuate the air in the mixing chamber and the experimental box; gas supply: starting the water vapor generator and the gas tank to deliver the gas to the mixing chamber according to the preset proportion of each component; mixing and monitoring: the gas is mixed multiple times in the mixing chamber, and the PLC controller monitors the fluid state at the outlet of the mixing chamber in real time and evaluates the mixing uniformity; feedback control: if the mixing uniformity does not reach the preset target, the PLC controller dynamically adjusts the output parameters of the gas supply unit until the mixing uniformity reaches the standard. Experiment execution: when the mixing uniformity is up to standard, the PLC controller opens the valve between the mixing chamber and the experimental box, the mixed gas is introduced into the experimental box, and the heating and mechanical property test is started.

8. The method of simulating a real gas environment of claim 7, wherein: In the mixing and monitoring, the PLC controller collects the single-point pressure time series signal at the outlet of the mixing chamber in real time, and substitutes it into the pulsation-mixing correlation model to calculate the current mixing degree distribution coefficient, which is used as the evaluation index of mixing uniformity.

9. The method of simulating a real gas environment of claim 7, wherein: The system characteristic constant η in the pulsation-mixing correlation model is determined to be 1.0-1.2 through pre-experiment and fluid simulation, and the exponential factor a is determined to be 1.5-2.

0.

10. The method of simulating a real gas environment of claim 7, wherein: In the gas supply, the volume fraction ratio of the introduced gas components is: nitrogen 70%-80%, oxygen 10%-20%, carbon dioxide about 5%, and water vapor about 5%.

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