Variable mach number wind tunnel control method

Abstract

The application provides a variable Mach number wind tunnel control method, which is applied to a variable Mach number wind tunnel including a combustion heater and a variable Mach number nozzle. The method first detects test environment establishment, obtains test requirement data including multiple target working conditions and parameters thereof, and a required steady state or dynamic test mode. In the steady state test mode, a path from a current working condition to a to-be-switched working condition is planned by judging flow field instability, and the variable Mach number nozzle and the combustion heater are controlled to perform corresponding actions, so that smooth switching is realized. In the dynamic test mode, a discrete division method is used to subdivide the switching path into multiple discrete working conditions, and working condition conversion is completed by gradually approaching each discrete working condition. The overall control logic of the operation method of the combustion heater and the variable Mach number nozzle is considered, and the rapid flexibility and continuous adjustment capability of the wind tunnel in the test are improved.

Description

Technical Field

[0001] This application relates to the field of wind tunnel control technology, and in particular to a variable Mach wind tunnel control method. Background Technology

[0002] In recent years, supersonic wind tunnel technology has been widely used to simulate the high-altitude flight environment of aircraft, including key parameters such as flight Mach number, altitude, and total temperature. Traditional supersonic wind tunnels can usually only simulate fixed flight environments, while variable Mach wind tunnels can simulate continuously changing flight environments under real flight trajectories, including dynamic parameters such as Mach number, flight altitude (static pressure), and total temperature, thus providing test conditions that are closer to actual flight.

[0003] A typical variable Mach wind tunnel consists of a combustion heater and a variable Mach nozzle. The combustion heater provides the required temperature, pressure, and flow rate of gas by controlling the ratio of combustion, oxidizer, and coolant, simulating the total pressure and temperature of flight, primarily employing a staged, sequential open-loop control method. The variable Mach nozzle, on the other hand, continuously changes the flow field of the gas exiting the combustion heater, simulating the flight Mach number and altitude, primarily employing a continuous feedback closed-loop control method. However, current control methods have limitations. For example, the staged, sequential open-loop control method cannot provide the required parameters in real time, affecting experimental flexibility, while the continuous feedback closed-loop control method may cause the combustion heater to fail to synchronously follow the nozzle state, resulting in experimental failure. Therefore, there is an urgent need to develop an overall control logic that can simultaneously consider the operation methods of both the combustion heater and the variable Mach nozzle to improve the wind tunnel's rapid flexibility and continuous adjustment capabilities during testing, while ensuring the reliability and safety of wind tunnel operation. Summary of the Invention

[0004] This application provides a variable Mach wind tunnel control method.

[0005] According to a first aspect of this application, a variable Mach wind tunnel control method is provided, applied to the main control system of a variable Mach wind tunnel, wherein the variable Mach wind tunnel further includes a combustion heater and a variable Mach nozzle, and the method includes:

[0006] Once the test environment is established, test requirement data is acquired. The test requirement data includes a test environment group and a test mode. The test environment group includes multiple target operating conditions and operating parameters for each target operating condition. The test mode includes a steady-state test mode and a dynamic test mode.

[0007] When the test mode is a steady-state test mode, the variable Mach wind tunnel is controlled by a steady-state operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on the multiple target operating conditions and the operating condition parameters of each target operating condition. The steady-state operating condition switching mechanism includes: judging the flow field instability based on the operating condition parameters of the current operating condition and the operating condition to be switched; determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result; and controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to the switching path, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched.

[0008] When the test mode is a dynamic test mode, the variable Mach wind tunnel is controlled by a dynamic operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on the multiple target operating conditions and the operating condition parameters of each target operating condition. The dynamic operating condition switching mechanism includes: discretizing the switching path of the current operating condition and the operating condition to be switched into multiple discrete operating conditions according to the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched; controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to the multiple discrete operating conditions, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched.

[0009] According to one embodiment of this application, determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result includes:

[0010] If the flow field is not unstable, construct a switching path that includes the current operating condition and the operating condition to be switched;

[0011] If the flow field becomes unstable, the path between the current operating condition and the operating condition to be switched is divided using the equal-interval segmentation method until the flow field stabilizes. At least one transitional operating condition is obtained from the segmentation, and a switching path is constructed that includes the current operating condition, at least one transitional operating condition, and the operating condition to be switched.

[0012] According to one embodiment of this application, controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to the switching path includes:

[0013] Obtain the operating parameters for each operating condition within the switching path;

[0014] Based on the operating parameters and execution priority mechanism of each operating condition within the switching path, the combustion heater and the variable Mach nozzle are controlled to execute the actions corresponding to each operating condition in sequence until the current operating condition is switched to the operating condition to be switched.

[0015] The execution priority mechanism includes: comparing the total incoming pressure and total incoming temperature of the current operating condition and the switching operating condition that needs to be switched to, based on the operating condition parameters of each operating condition, and comparing the switching time of the combustion heater and the switching time of the variable Mach nozzle, to obtain the total pressure comparison result, total temperature comparison result, and switching time comparison result; determining the start-up priority and start-up time of the combustion heater and the variable Mach nozzle based on the total pressure comparison result, total temperature comparison result, switching time comparison result, and the system synchronization mechanism; and controlling the combustion heater and the variable Mach nozzle to perform corresponding actions based on the start-up priority and start-up time of the combustion heater and the variable Mach nozzle, as well as the operating condition parameters of the current operating condition and the switching operating condition that needs to be switched to.

[0016] According to one embodiment of this application, the operating parameters include Mach number; correspondingly,

[0017] The step involves discretizing the switching path of the current operating condition and the operating condition to be switched into multiple discrete operating conditions based on the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched, including:

[0018] Determine the discrete number based on the Mach number of the current operating condition and the operating condition to be switched;

[0019] Based on the discrete number, the path between the current operating condition and the operating condition to be switched is discretized into multiple discrete operating conditions corresponding to the discrete number.

[0020] According to one embodiment of this application, controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to multiple discrete operating conditions includes:

[0021] Obtain the operating parameters for each discrete operating condition;

[0022] Based on the operating parameters of each discrete operating condition, the combustion heater and the variable Mach nozzle are controlled to simultaneously and sequentially execute actions corresponding to each discrete operating condition until the current operating condition is switched to the operating condition to be switched.

[0023] According to one embodiment of this application, the variable Mach wind tunnel further includes a low-pressure exhaust system, a high-altitude test chamber, a test specimen placed in the high-altitude test chamber, and the variable Mach nozzle, the combustion heater, the low-pressure exhaust system, and the cooling system of the high-altitude test chamber; correspondingly,

[0024] The test environment was established through the following steps:

[0025] Control the variable Mach nozzle to move the nozzle to the preset initial nozzle position;

[0026] The combustion heater is controlled to move the regulating valve to the preset valve initial position;

[0027] Start all cooling systems;

[0028] Receives the initial power-on signal and, in response to the initial power-on signal, performs the power-on operation according to the set power-on logic;

[0029] Once the power-on operation is detected as complete, the test environment setup is confirmed to be successful.

[0030] The startup logic includes: controlling the low-pressure exhaust system to start; controlling the combustion heater to start when the pressure inside the high-altitude test chamber is detected to be stable; and determining that the startup operation is complete if no startup failure signal is received from the combustion heater within a set time period.

[0031] According to one embodiment of this application, the method further includes:

[0032] Upon detection that the test is complete, the combustion heater and the variable Mach nozzle are shut down according to the set shutdown logic.

[0033] The shutdown logic includes: sending a shutdown signal to the combustion heater and the variable Mach nozzle, so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal; when the combustion heater shuts down, controlling the combustion heater to perform nitrogen purging and air purging; when the purging is completed, sending a shutdown signal to all cooling systems and sending a nozzle return signal to the variable Mach nozzle, so that all cooling systems shut down in response to the shutdown signal, and the variable Mach nozzle moves the nozzle to a preset initial nozzle position in response to the initial return signal.

[0034] According to one embodiment of this application, controlling the combustion heater to perform nitrogen purging and air purging includes:

[0035] Send a nitrogen purging signal to the combustion heater so that the combustion heater starts nitrogen purging in response to the nitrogen purging signal;

[0036] Once nitrogen purging is complete, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal.

[0037] When the low-pressure exhaust system is shut down, an air purge signal is sent to the combustion heater so that the combustion heater performs air purging in response to the air purge signal.

[0038] According to one embodiment of this application, the method further includes:

[0039] Upon receiving a cooling emergency stop signal, a shutdown signal is sent to the combustion heater and the variable Mach nozzle, so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal.

[0040] When the variable Mach nozzle and the combustion heater have been shut down, the faulty cooling system that triggered the cooling emergency stop signal is detected, and a shutdown signal is sent to the faulty cooling system.

[0041] When the failure cooling system has been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal.

[0042] Once the low-pressure exhaust system has been shut down, a shutdown signal is sent to other cooling systems.

[0043] According to one embodiment of this application, the variable Mach wind tunnel further includes a fault system; correspondingly,

[0044] The method further includes:

[0045] Receive the emergency stop signal sent by the faulty system when a fault is detected;

[0046] A shutdown signal is sent to the combustion heater and the variable Mach nozzle so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal;

[0047] When the variable Mach nozzle and the combustion heater have been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal.

[0048] Once the low-pressure exhaust system has been shut down, a shutdown signal is sent to all cooling systems.

[0049] This application discloses a variable Mach wind tunnel control method. First, it detects the establishment of the test environment, acquires test requirement data including multiple target operating conditions and their parameters, and the required steady-state or dynamic test modes. In the steady-state test mode, by judging the instability of the flow field, it plans the path from the current operating condition to the condition to be switched, and controls the variable Mach nozzle and combustion heater to perform corresponding actions to achieve a smooth switch. In the dynamic test mode, a discrete segmentation method is used to subdivide the switching path into multiple discrete operating conditions, and the operating condition transition is completed by gradually approximating each discrete operating condition. This method achieves a balance between the overall control logic of the combustion heater and variable Mach nozzle operation methods, improving the wind tunnel's rapid flexibility and continuous adjustment capability during testing.

[0050] It should be understood that the teachings of this application are not required to achieve all the beneficial effects described above, but rather that a specific technical solution can achieve a specific technical effect, and other embodiments of this application can also achieve beneficial effects not mentioned above. Attached Figure Description

[0051] The above and other objects, features, and advantages of exemplary embodiments of this application will become readily apparent from the following detailed description taken in conjunction with the accompanying drawings. Several embodiments of this application are illustrated in the drawings by way of example and not limitation, wherein:

[0052] In the accompanying drawings, the same or corresponding reference numerals indicate the same or corresponding parts.

[0053] Figure 1 A schematic diagram of the composition and structure of the variable Mach wind tunnel provided in an embodiment of this application is shown;

[0054] Figure 2 A schematic diagram illustrating the implementation flow of the variable Mach wind tunnel control method provided in an embodiment of this application is shown.

[0055] Figure 3 A schematic diagram illustrating the implementation flow of the path switching operation of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0056] Figure 4 A schematic diagram illustrating the startup operation of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0057] Figure 5 A schematic diagram illustrating the implementation process of the cooling emergency stop operation of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0058] Figure 6 A schematic diagram illustrating the implementation process of the fault emergency stop operation of the variable Mach wind tunnel control method provided in this application embodiment is shown. Detailed Implementation

[0059] To make the objectives, features, and advantages of this application more apparent and understandable, the technical solutions in the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0060] Figure 1 A schematic diagram of the composition and structure of the variable Mach wind tunnel provided in an embodiment of this application is shown.

[0061] refer to Figure 1This application provides a variable Mach wind tunnel, which includes multiple core modules such as a main control system, a combustion heater, a variable Mach nozzle, a high-altitude test chamber (including test specimens), and a low-pressure exhaust system. It also includes cooling systems for the combustion heater, variable Mach nozzle, high-altitude test chamber, and low-pressure exhaust system. The variable Mach wind tunnel control method of this application is applied to the main control system of the variable Mach wind tunnel. The main control system is connected to the combustion heater, variable Mach nozzle, high-altitude test chamber, low-pressure exhaust system, and all cooling systems, enabling control and communication with each component.

[0062] Figure 2 A schematic diagram illustrating the implementation flow of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0063] refer to Figure 2 This application provides a variable Mach wind tunnel control method, applicable to wind tunnels including the above-mentioned... Figure 1 The main control system of the variable Mach wind tunnel, the method includes:

[0064] Operation 101: Upon detecting that the test environment has been established, acquire the test requirement data. The test requirement data includes the test environment group and the test mode. The test environment group includes multiple target operating conditions and the operating parameters of each target operating condition. The test mode includes steady-state test mode and dynamic test mode.

[0065] Before conducting an experiment, it is necessary to establish an experimental environment in advance. Once the experimental environment is established, obtain the experimental requirement data needed to conduct the experiment and then begin the experiment.

[0066] The test requirements data include test environment groups and test modes. Tests typically refer to testing the state of the test piece under various flight environments. Flight environments are simulated based on operating conditions. Therefore, during testing, it is necessary to acquire test environment groups that include multiple target operating conditions. Each target operating condition can be considered as a simulation of a flight environment. Switching operating conditions can be regarded as a change in operating condition parameters. Therefore, in order to achieve switching between target operating conditions, it is also necessary to acquire the operating condition parameters of each target operating condition.

[0067] In one embodiment of this application, the operating parameters are configured in advance by the tester or calculated by the main control system based on environmental parameters and the characteristics of the variable Mach nozzle and the combustion heater. The operating parameters may include, but are not limited to, Mach number, altitude, total temperature, total pressure, flow rate and temperature output by the combustion heater, the corresponding position of the regulating valve, and the nozzle position of the variable Mach nozzle.

[0068] When the experiment only requires multiple fixed flight environments, the state during the switching between different flight environments does not need to be considered. In this case, the wind tunnel can complete the switching of operating conditions as quickly as possible under the premise of stable flow field. However, when the experiment requires not only multiple flight environments but also to simulate dynamic flight environments, it is necessary to ensure the continuity of the operating condition switching state and the environmental matching of flight speed and altitude. Therefore, the embodiments of this application also configure test modes, with a steady-state test mode to adapt to scenarios that only require fixed flight environments, and a dynamic test mode to adapt to scenarios that require simulating dynamic flight environments.

[0069] Before an experiment is required, the experiment mode for which the experiment is needed has already been configured, so it can be retrieved when the experiment is needed.

[0070] Operation 102: In the steady-state test mode, the variable Mach wind tunnel is controlled based on the steady-state operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on multiple target operating conditions and the operating parameters of each target operating condition. The steady-state operating condition switching mechanism includes: judging the flow field instability based on the operating parameters of the current operating condition and the operating condition to be switched; determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result; and controlling the variable Mach nozzle and combustion heater to perform actions corresponding to the switching path, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched.

[0071] The main difference between steady-state test mode and dynamic test mode lies in the switching process of operating conditions. Steady-state test mode does not need to consider the dynamic stability of the flight environment. Therefore, when switching operating conditions, the fastest possible switching can be achieved while ensuring that the flow field does not become unstable.

[0072] To achieve steady-state test mode, a steady-state operating condition switching mechanism is configured for its operating condition transition. The main purpose of the steady-state operating condition switching mechanism is to determine the switching path under stable flow field conditions. Specifically, it includes determining whether a direct switch between the current operating condition and the operating condition to be switched can guarantee flow field stability. Then, based on the flow field stability judgment result and the operating parameters of the current operating condition and the operating condition to be switched, the switching path is determined.

[0073] In one embodiment of this application, determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result includes: if the flow field is not unstable, constructing a switching path that includes the current operating condition and the operating condition to be switched; if the flow field is unstable, using an equal-interval segmentation method to segment the path between the current operating condition and the operating condition to be switched until the flow field stabilizes, obtaining at least one transitional operating condition obtained from the segmentation, and constructing a switching path that includes the current operating condition, at least one transitional operating condition, and the operating condition to be switched.

[0074] If a direct switch can guarantee that the flow field will not become unstable, then the current operating condition is directly switched to the operating condition to be switched, which is determined as the feasible switching path. If a direct switch cannot guarantee that the flow field will not become unstable, then the path from the current operating condition to the operating condition to be switched needs to be segmented until the flow field becomes stable. The path segmentation can be done using an equal-interval segmentation method, which can be seen as dividing the current operating condition and the operating condition to be switched into multiple equally spaced transitional operating conditions. Specifically, if the calculation indicates that a flow field instability problem will occur, an automatic transitional operating condition is set, and this transitional operating condition is set as the new endpoint operating condition (the operating condition to be switched). Then, the flow field instability judgment is performed, and the above process of setting the transitional operating condition is repeated until the instability problem no longer occurs. Accordingly, the main control system converts the switching path from the current operating condition to the operating condition to be switched into a switching path that includes several stable transitional operating conditions.

[0075] In one embodiment of this application, the instability of the flow field can be determined using the following formula:

[0076]

[0077] Where T0 represents total temperature, P0 represents total pressure, γ represents specific heat ratio of airflow, Ma represents Mach number, and P s This indicates the pressure inside the test chamber. Total temperature, total pressure, and Mach number can all be calculated in real time by the main control system when needed and are included in the operating parameters. The pressure inside the test chamber can be obtained based on the main control system's monitoring of the high-altitude test chamber.

[0078] After determining the final transitional operating condition, the combustion heater and the variable Mach nozzle are controlled to perform actions corresponding to the operating parameters of the corresponding operating conditions in sequence. Specifically, the combustion heater's actions can be viewed as adjusting the position of its regulating valve, and the variable Mach nozzle's actions can be viewed as moving the nozzle position.

[0079] When all operating conditions of the switching path have been switched, the variable Mach nozzle and combustion heater will send a signal indicating that the switching is complete. At this time, the main control system determines that the operating condition switching is complete.

[0080] Operation 103: In the dynamic test mode, the variable Mach wind tunnel is controlled by a dynamic operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on multiple target operating conditions and the operating condition parameters of each target operating condition. The dynamic operating condition switching mechanism includes: discretizing the switching path of the current operating condition and the operating condition to be switched into multiple discrete operating conditions according to the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched; controlling the variable Mach nozzle and combustion heater to perform actions corresponding to the multiple discrete operating conditions, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched.

[0081] In dynamic test mode, it is necessary to consider the dynamic state during flight environment switching to ensure continuous adjustment of the combustion heater. Therefore, a dynamic operating condition switching mechanism is configured for dynamic test mode. The main purpose of the dynamic operating condition switching mechanism is to divide the switching between two operating conditions into multiple adjacent operating conditions (discrete operating conditions) through discrete segmentation.

[0082] In one embodiment of this application, the operating condition parameters include the Mach number; accordingly, based on the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched, the switching path of the current operating condition and the operating condition to be switched is discretized into multiple discrete operating conditions, including: determining a discrete number based on the Mach number of the current operating condition and the operating condition to be switched; and discretizing the path between the current operating condition and the operating condition to be switched into multiple discrete operating conditions corresponding to the discrete number based on the discrete number.

[0083] The specific operating parameters may include Mach number, altitude, total temperature, and total pressure. The process of discretizing multiple discrete operating conditions may include: calculating the number of discrete conditions n based on the Mach number, dividing the Mach number, altitude, total temperature, and total pressure between the current operating condition and the operating condition to be switched into n equal parts, thus obtaining n discrete operating conditions and their corresponding operating parameters.

[0084] In one embodiment of this application, the discrete number can be calculated using the following formula:

[0085]

[0086] Where n represents a discrete number, Ma1 represents the Mach number of the current operating condition, and Ma2 represents the Mach number of the operating condition to be switched.

[0087] For example, assuming the initial operating condition (current operating condition) has a Mach number Ma1 and an altitude H1, and the final operating condition (operating condition to be switched) has a Mach number Ma2 and an altitude H2, the discrete number can be calculated as follows: Then, the altitude is divided into H1 to H according to this number n. n The corresponding total temperatures are divided into T01 to T0. n The total pressure is divided into P01 to P0. n Finally, the above dynamic switching process is transformed into n discrete operating conditions, each of which includes corresponding operating parameters such as Mach number, altitude, total temperature, and total pressure.

[0088] In one embodiment of this application, controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to multiple discrete operating conditions includes: acquiring operating condition parameters for each discrete operating condition; and controlling the combustion heater and the variable Mach nozzle to simultaneously and sequentially perform actions corresponding to each discrete operating condition based on the operating condition parameters for each discrete operating condition, until the current operating condition is switched to the operating condition to be switched.

[0089] After determining each discrete operating condition, the combustion heater and variable Mach nozzle are controlled to perform corresponding actions according to the switching sequence of the discrete operating conditions, based on the operating parameters of each discrete operating condition. Specifically, when a switch between discrete operating conditions is required, the operating parameters for each discrete operating condition are expanded by the main control system based on Mach number, altitude, total temperature, and total pressure to include the output flow rate, temperature, and regulating valve position of the combustion heater, as well as the nozzle position of the variable Mach nozzle. Thus, when performing a discrete operating condition switch, the combustion heater and variable Mach nozzle perform corresponding actions according to the expanded operating parameters, thereby completing the operating condition switch.

[0090] In one embodiment of this application, the operation of the combustion heater and the variable Mach nozzle under each discrete operating condition includes: in each discrete operating condition, after the main control system receives the end signal of the previous discrete operating condition, it simultaneously sends an operating condition switching signal and the discrete switching target to the combustion heater and the variable Mach nozzle and starts timing. The combustion heater and the variable Mach nozzle operate automatically according to the switching target. The combustion heater does not send a completion signal to the main control system after switching, while the variable Mach nozzle sends a completion signal to the main control system after switching. After the main control system receives the signal and times for more than 0.8 seconds, it sends the end signal for the current discrete operating condition switch and begins the switch to the next discrete operating condition. The switching target is the operating condition parameter of the expanded discrete operating condition.

[0091] Thus, the solution in this embodiment first detects the establishment of the test environment, acquires test requirement data including multiple target operating conditions and their parameters, and the required steady-state or dynamic test mode. In the steady-state test mode, by judging the instability of the flow field, the path from the current to the operating condition to be switched is planned, and the variable Mach nozzle and combustion heater are controlled to perform corresponding actions to achieve a smooth switch. In the dynamic test mode, the switching path is subdivided into multiple discrete operating conditions using a discrete segmentation method, and the operating condition is completed by gradually approximating each discrete operating condition. This achieves a balance between the overall control logic of the combustion heater and variable Mach nozzle operation methods, improves the rapid flexibility and continuous adjustment capability of the variable Mach wind tunnel in the test, ensures that the variable Mach wind tunnel can quickly and flexibly continuously adjust the test environment in the test state, accurately match the flight Mach number and flight altitude environment, and at the same time ensure that the variable Mach wind tunnel can respond to immediate needs to change the Mach number and flight environment. It also realizes the autonomous selection of steady-state and dynamic tests by the variable Mach wind tunnel.

[0092] Figure 3 This paper illustrates a schematic diagram of the path switching operation implementation process of the variable Mach wind tunnel control method provided in an embodiment of this application.

[0093] refer to Figure 3In one embodiment of this application, controlling the variable Mach nozzle and combustion heater to perform actions corresponding to the switching path includes: operation 201, acquiring operating parameters for each operating condition within the switching path; operation 202, controlling the combustion heater and variable Mach nozzle to sequentially perform actions corresponding to each operating condition according to the operating parameters of each operating condition within the switching path and an execution priority mechanism, until the current operating condition is switched to the operating condition to be switched; wherein, the execution priority mechanism includes: comparing the current operating condition with the switching operating condition that needs to be switched according to the operating parameters of each operating condition. The total incoming pressure and total incoming temperature are calculated and compared with the switching time of the combustion heater and the switching time of the variable Mach nozzle to obtain the total pressure comparison result, total temperature comparison result, and switching time comparison result. Based on the total pressure comparison result, total temperature comparison result, switching time comparison result, and system synchronization mechanism, the start-up priority and start-up time of the combustion heater and the variable Mach nozzle are determined. Based on the start-up priority and start-up time of the combustion heater and the variable Mach nozzle, as well as the operating parameters of the current operating condition and the switching operating condition that needs to be switched, the combustion heater and the variable Mach nozzle are controlled to perform corresponding actions.

[0094] During steady-state test mode, to ensure the coordination between the variable Mach nozzle and the combustion heater, it is necessary to determine their execution priorities and start-up times so that they can work together during the switching process. To achieve this coordination, this application embodiment configures an execution priority mechanism to determine the execution priorities and start-up times of the variable Mach nozzle and the combustion heater, and controls them to perform corresponding actions.

[0095] The purpose of the priority mechanism is primarily to determine which of the variable Mach nozzle and the combustion heater should start first during each operating condition switch. The purpose of the system synchronization mechanism is to ensure that the end times of the combustion heater and the variable Mach nozzle are kept as synchronized as possible during each operating condition switch. Specifically, the priority mechanism includes: comparing the incoming total pressure and total temperature shown in the operating parameters of the current operating condition and the operating condition to be switched to; comparing the switching time taken by the combustion heater and the variable Mach nozzle to switch from the current operating condition to the operating condition to be switched to; obtaining the total pressure comparison result, the total temperature comparison result, and the switching time comparison result; and finally, based on the total pressure comparison result, the total temperature comparison result, the switching time comparison result, and the system synchronization mechanism, determining the start-up priority and start-up time of the combustion heater and the variable Mach nozzle, and controlling the combustion heater and the variable Mach nozzle to perform the corresponding actions.

[0096] In one embodiment of this application, the start-up priority and start-up time of the combustion heater and the variable Mach nozzle are determined based on the total pressure comparison results, total temperature comparison results, switching time comparison results, and the system synchronization mechanism, including:

[0097] When the total pressure comparison result and total temperature comparison result show that the incoming total pressure or total temperature has increased, if the switching time comparison result shows that the switching time of the combustion heater is less than the switching time of the variable Mach nozzle, the main control system first issues a variable Mach nozzle start signal to control the variable Mach nozzle to start first, and then calculates the start time of the combustion heater through the switching time point of the variable Mach nozzle, and issues a start signal of the combustion heater at the start time point to control the combustion heater to start.

[0098] When the total pressure comparison result and the total temperature comparison result show that the incoming total pressure or total temperature has increased, if the switching time comparison result shows that the switching time of the combustion heater is greater than the switching time of the variable Mach nozzle, the main control system simultaneously issues start signals for the variable Mach nozzle and the combustion heater, controlling the variable Mach nozzle and the combustion heater to start simultaneously.

[0099] When the total pressure comparison result and the total temperature comparison result show that the incoming total pressure or total temperature has decreased, if the switching time comparison result shows that the switching time of the combustion heater is less than the switching time of the variable Mach nozzle, the main control system simultaneously issues start signals for the variable Mach nozzle and the combustion heater, controlling the variable Mach nozzle and the combustion heater to start simultaneously.

[0100] When the total pressure comparison result and total temperature comparison result show that the incoming total pressure or total temperature has decreased, if the switching time comparison result shows that the switching time of the combustion heater is greater than the switching time of the variable Mach nozzle, the main control system first issues a combustion heater start signal to control the combustion heater to start. Then, it calculates the start time of the variable Mach nozzle by using the time point when the combustion heater completes the switching, and issues a combustion heater start signal at that start time point to control the combustion heater to start.

[0101] Figure 4 The diagram illustrates the startup process of the variable Mach wind tunnel control method provided in this application embodiment.

[0102] refer to Figure 4 In one embodiment of this application, reference is made to Figure 1 The variable Mach wind tunnel includes a low-pressure exhaust system, a high-altitude test chamber, test specimens placed in the high-altitude test chamber, as well as variable Mach nozzles, combustion heaters, and cooling systems for the low-pressure exhaust system and the high-altitude test chamber. Once the test environment of operation 101 is established, it can be tested through the following operations:

[0103] Operation 301 controls the variable Mach nozzle to move the nozzle to the preset initial nozzle position;

[0104] Operation 302 controls the combustion heater to move the regulating valve to the preset valve initial position;

[0105] Operation 303: Activate all cooling systems;

[0106] Operation 304: Receive the initial power-on signal and, in response to the initial power-on signal, execute the power-on operation according to the set power-on logic;

[0107] Operation 305: Upon detecting that the power-on operation is complete, the test environment is determined to be established. The power-on logic includes: controlling the low-pressure exhaust system to start; controlling the combustion heater to start when the pressure inside the high-altitude test chamber is detected to be stable; and determining that the power-on operation is complete if no power-on failure signal is received from the combustion heater within a set time period.

[0108] In addition to the testing process, in order to achieve the main control of the variable Mach wind tunnel, it is also equipped with control methods for normal start-up, normal shutdown, cooling emergency stop and fault emergency stop of the variable Mach wind tunnel.

[0109] Once the test environment is established, it can be considered as a successful start-up. The start-up control process is as follows: Before start-up, the main control system moves the variable Mach nozzle to the preset initial nozzle position (corresponding to the preset initial Mach number) and moves the regulating valve of the combustion heater to the preset initial valve position (corresponding to the position required for the preset initial flight environment). Then, the cooling system is activated. After receiving the initial start-up signal, the low-pressure exhaust system is activated. Once the pressure inside the high-altitude test chamber stabilizes, the pressure P inside the high-altitude test chamber is recorded. s The system then sends a power-on completion signal. Two seconds after sending the power-on completion signal, the main control system sends a power-on signal to the combustion heater. If no power-on failure signal is received from the combustion heater, the system counts down for 6 seconds to mark the completion of the test environment setup, and the test can then proceed.

[0110] In one embodiment of this application, a control method for normal shutdown of a variable Mach wind tunnel is also provided, specifically including: upon detection of test completion, controlling the combustion heater and variable Mach nozzle to shut down according to a set shutdown logic; wherein, the set shutdown logic includes: sending a shutdown signal to the combustion heater and variable Mach nozzle to cause the variable Mach nozzle and combustion heater to shut down in response to the shutdown signal; when the combustion heater has shut down, controlling the combustion heater to perform nitrogen purging and air purging; when purging is completed, sending a shutdown signal to all cooling systems and sending a nozzle return signal to the variable Mach nozzle to cause the cooling systems to shut down in response to the shutdown signal, and the variable Mach nozzle to move the nozzle to a preset initial nozzle position in response to the initial return signal.

[0111] In one embodiment of this application, controlling the combustion heater to perform nitrogen purging and air purging includes: sending a nitrogen purging signal to the combustion heater to cause the combustion heater to start nitrogen purging in response to the nitrogen purging signal; after nitrogen purging is completed, sending a shutdown signal to the low-pressure exhaust system to cause the low-pressure exhaust system to shut down in response to the shutdown signal; and after the low-pressure exhaust system is shut down, sending an air purging signal to the combustion heater to cause the combustion heater to perform air purging in response to the air purging signal.

[0112] Specifically, the entire control process for a normal shutdown is as follows: After the test is completed, the main control system sends a shutdown signal to the combustion heater and the variable Mach nozzle. Upon receiving the shutdown signal, the variable Mach nozzle, regardless of its current state, immediately stops operating and maintains its position. Upon receiving the shutdown signal, the combustion heater shuts down according to the normal procedure (disconnecting combustion and oxidizer supply). After shutdown, it sends a shutdown completion signal back to the main control system and simultaneously initiates nitrogen purging for at least 20 seconds to remove residual fuel in the gaps of the combustion heater and variable Mach nozzle. After nitrogen purging, it sends a completion signal back to the main control system. Upon receiving this signal, the main control system sends a shutdown signal to the low-pressure exhaust system. Upon receiving the signal, the low-pressure exhaust system begins a slow shutdown procedure and sends a completion signal upon shutdown. Upon receiving this signal, the main control system sends an air purging signal to the combustion heater, which then begins air purging to cool the entire wind tunnel.

[0113] The air purging time is determined by the main control system based on the highest total temperature (included in the operating parameters). When the highest total temperature reaches 1600K or above, the purging time shall not be less than 90s; when the highest total temperature reaches 1300K or above, the purging time shall not be less than 60s; when the highest total temperature reaches 1000K or above, the purging time shall not be less than 45s; when the highest total temperature reaches 700K or above, the purging time shall not be less than 30s; when the highest total temperature reaches 500K or above, the purging time shall not be less than 15s; and when the highest total temperature reaches 400K or above, the purging time shall not be less than 10s.

[0114] During the air purging process, the main control system performs timing monitoring. When the purging time reaches the target time, the main control system simultaneously sends a cooling system shutdown signal and a variable Mach nozzle return signal, thereby shutting down the cooling system and returning the variable Mach nozzle to the preset initial nozzle position.

[0115] Figure 5 A schematic diagram illustrating the implementation process of the cooling emergency stop operation of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0116] In one embodiment of this application, the method further includes cooling emergency stop control, specifically including:

[0117] Operation 401: Upon receiving a cooling emergency stop signal, a shutdown signal is sent to the combustion heater and the variable Mach nozzle, so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal.

[0118] Operation 402: After the variable Mach nozzle and combustion heater have been shut down, detect the faulty cooling system that triggered the cooling emergency stop signal and send a shutdown signal to the faulty cooling system.

[0119] Operation 403: After the faulty cooling system has been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal.

[0120] Operation 404 sends a shutdown signal to other cooling systems after the low-pressure exhaust system has been shut down.

[0121] Overpressure in the cooling system can damage the equipment due to water pressure. In this case, the cooling system must be shut down first to prevent damage from high temperatures. When the main control system receives this emergency stop signal, it sends shutdown signals to the combustion heater and the variable Mach nozzle. Upon receiving the shutdown signal, the variable Mach nozzle, regardless of its current state, immediately stops operating and maintains its position. Upon receiving the shutdown signal, the combustion heater shuts down according to the normal procedure (disconnecting combustion and oxidizer supply), and sends a shutdown completion signal back to the main control system. One second after receiving the shutdown signal, the main control system sends a shutdown signal to the faulty cooling system. Meanwhile, after the combustion heater completes shutdown and sends a shutdown completion signal back to the main control system, the main control system sends a shutdown signal to the low-pressure exhaust system. Upon receiving the signal, the low-pressure exhaust system begins a slow shutdown procedure and sends a completion signal upon completion. Sixty seconds after receiving the low-pressure exhaust system's shutdown completion signal, the main control system sends shutdown signals to the other cooling systems.

[0122] Figure 6 A schematic diagram illustrating the implementation process of the fault emergency stop operation of the variable Mach wind tunnel control method provided in this application embodiment is shown.

[0123] refer to Figure 6 In one embodiment of this application, the method further includes a fault emergency stop operation, and the variable Mach wind tunnel further includes a fault system. The fault emergency stop operation specifically includes:

[0124] Operation 501: Receive the emergency stop signal sent by the faulty system when a fault is detected;

[0125] Operation 502: Send a shutdown signal to the combustion heater and the variable Mach nozzle so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal;

[0126] Operation 503: After the variable Mach nozzle and combustion heater have been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal.

[0127] Operation 504 sends a shutdown signal to all cooling systems after the low-pressure exhaust system has been shut down.

[0128] When a malfunction in the variable Mach wind tunnel itself prevents its normal operation, the wind tunnel must be shut down immediately. However, the cooling system must remain operational to prevent overheating and damage to the wind tunnel. Upon malfunction, the faulty system sends an emergency stop signal to the main control system. Upon receiving this signal, the main control system issues shutdown signals to the combustion heater and the variable Mach nozzle. The variable Mach nozzle, upon receiving the shutdown signal, immediately stops operating and maintains its position, regardless of its current state. The combustion heater, upon receiving the shutdown signal, shuts down according to the normal procedure (disconnecting combustion and oxidizer supply). After shutdown, it sends a shutdown completion signal to the main control system. The main control system, upon receiving the shutdown signal, sends a shutdown signal to the low-pressure exhaust system 0.5 seconds later. Sixty seconds after the low-pressure exhaust system has shut down, the main control system sends a shutdown signal to all cooling systems.

[0129] Thus, the method in this application embodiment, through the design of the start-up, shutdown, cooling emergency stop, and fault emergency stop operations of the variable Mach wind tunnel, ensures the compatibility of the control logic of each system of the variable Mach wind tunnel, and ensures that the various systems of the variable Mach wind tunnel operate in coordination, safely and reliably.

[0130] It should be understood that the various forms of processes shown above can be used to rearrange, add, or delete steps. For example, the steps described in this application can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution disclosed in this application can be achieved, and this is not limited herein.

[0131] The above description is merely a specific embodiment of this application, but the scope of protection of this application is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the scope of the claims.

Claims

1. A variable Mach wind tunnel control method, characterized in that, A main control system for a variable Mach wind tunnel, the variable Mach wind tunnel further including a combustion heater and a variable Mach nozzle, the method comprising: Once the test environment is established, test requirement data is acquired. The test requirement data includes a test environment group and a test mode. The test environment group includes multiple target operating conditions and operating parameters for each target operating condition. The test mode includes a steady-state test mode and a dynamic test mode. When the test mode is a steady-state test mode, the variable Mach wind tunnel is controlled by a steady-state operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on the multiple target operating conditions and the operating condition parameters of each target operating condition. The steady-state operating condition switching mechanism includes: judging the flow field instability based on the operating condition parameters of the current operating condition and the operating condition to be switched; determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result; and controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to the switching path, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched. When the test mode is a dynamic test mode, the variable Mach wind tunnel is controlled by a dynamic operating condition switching mechanism to simulate and test the flight environment corresponding to each target operating condition based on the multiple target operating conditions and the operating condition parameters of each target operating condition. The dynamic operating condition switching mechanism includes: discretizing the switching path of the current operating condition and the operating condition to be switched into multiple discrete operating conditions according to the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched; controlling the variable Mach nozzle and the combustion heater to perform actions corresponding to the multiple discrete operating conditions, so as to control the variable Mach wind tunnel to switch from the current operating condition to the operating condition to be switched.

2. The method according to claim 1, characterized in that, The step of determining the switching path between the current operating condition and the operating condition to be switched based on the flow field instability judgment result includes: If the flow field is not unstable, construct a switching path that includes the current operating condition and the operating condition to be switched; If the flow field becomes unstable, the path between the current operating condition and the operating condition to be switched is divided using the equal-interval segmentation method until the flow field stabilizes. At least one transitional operating condition is obtained from the segmentation, and a switching path is constructed that includes the current operating condition, at least one transitional operating condition, and the operating condition to be switched.

3. The method according to claim 1, characterized in that, The control of the variable Mach nozzle and the combustion heater to perform actions corresponding to the switching path includes: Obtain the operating parameters for each operating condition within the switching path; Based on the operating parameters and execution priority mechanism of each operating condition within the switching path, the combustion heater and the variable Mach nozzle are controlled to execute the actions corresponding to each operating condition in sequence until the current operating condition is switched to the operating condition to be switched. The execution priority mechanism includes: comparing the total incoming pressure and total incoming temperature of the current operating condition and the switching operating condition that needs to be switched to, based on the operating condition parameters of each operating condition, and comparing the switching time of the combustion heater and the switching time of the variable Mach nozzle, to obtain the total pressure comparison result, total temperature comparison result, and switching time comparison result; determining the start-up priority and start-up time of the combustion heater and the variable Mach nozzle based on the total pressure comparison result, total temperature comparison result, switching time comparison result, and the system synchronization mechanism; and controlling the combustion heater and the variable Mach nozzle to perform corresponding actions based on the start-up priority and start-up time of the combustion heater and the variable Mach nozzle, as well as the operating condition parameters of the current operating condition and the switching operating condition that needs to be switched to.

4. The method according to claim 1, characterized in that, The operating parameters include the Mach number; correspondingly... The step involves discretizing the switching path of the current operating condition and the operating condition to be switched into multiple discrete operating conditions based on the discrete segmentation method and the operating condition parameters of the current operating condition and the operating condition to be switched, including: Determine the discrete number based on the Mach number of the current operating condition and the operating condition to be switched; Based on the discrete number, the path between the current operating condition and the operating condition to be switched is discretized into multiple discrete operating conditions corresponding to the discrete number.

5. The method according to claim 1, characterized in that, The control of the variable Mach nozzle and the combustion heater to perform actions corresponding to multiple discrete operating conditions includes: Obtain the operating parameters for each discrete operating condition; Based on the operating parameters of each discrete operating condition, the combustion heater and the variable Mach nozzle are controlled to simultaneously and sequentially execute actions corresponding to each discrete operating condition until the current operating condition is switched to the operating condition to be switched.

6. The method according to claim 1, characterized in that, The variable Mach wind tunnel also includes a low-pressure exhaust system, a high-altitude test chamber, a test specimen placed in the high-altitude test chamber, the variable Mach nozzle, the combustion heater, the low-pressure exhaust system, and the cooling system of the high-altitude test chamber; correspondingly, The test environment was established through the following steps: Control the variable Mach nozzle to move the nozzle to the preset initial nozzle position; The combustion heater is controlled to move the regulating valve to the preset valve initial position; Start all cooling systems; Receives the initial power-on signal and, in response to the initial power-on signal, performs the power-on operation according to the set power-on logic; Once the power-on operation is detected as complete, the test environment setup is confirmed to be successful. The startup logic includes: controlling the low-pressure exhaust system to start; controlling the combustion heater to start when the pressure inside the high-altitude test chamber is detected to be stable; and determining that the startup operation is complete if no startup failure signal is received from the combustion heater within a set time period.

7. The method according to claim 6, characterized in that, The method further includes: Upon detection that the test is complete, the combustion heater and the variable Mach nozzle are shut down according to the set shutdown logic. The shutdown logic includes: sending a shutdown signal to the combustion heater and the variable Mach nozzle, so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal; when the combustion heater shuts down, controlling the combustion heater to perform nitrogen purging and air purging; when the purging is completed, sending a shutdown signal to all cooling systems and sending a nozzle return signal to the variable Mach nozzle, so that all cooling systems shut down in response to the shutdown signal, and the variable Mach nozzle moves the nozzle to a preset initial nozzle position in response to the nozzle return signal.

8. The method according to claim 7, characterized in that, The control of the combustion heater to perform nitrogen purging and air purging includes: Send a nitrogen purging signal to the combustion heater so that the combustion heater starts nitrogen purging in response to the nitrogen purging signal; Once nitrogen purging is complete, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal. When the low-pressure exhaust system is shut down, an air purge signal is sent to the combustion heater so that the combustion heater performs air purging in response to the air purge signal.

9. The method according to claim 6, characterized in that, The method further includes: Upon receiving a cooling emergency stop signal, a shutdown signal is sent to the combustion heater and the variable Mach nozzle, so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal. When the variable Mach nozzle and the combustion heater have been shut down, the faulty cooling system that triggered the cooling emergency stop signal is detected, and a shutdown signal is sent to the faulty cooling system. When the failure cooling system has been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal. Once the low-pressure exhaust system has been shut down, a shutdown signal is sent to other cooling systems.

10. The method according to claim 6, characterized in that, The variable Mach wind tunnel also includes a fault system; correspondingly... The method further includes: Receive the emergency stop signal sent by the faulty system when a fault is detected; A shutdown signal is sent to the combustion heater and the variable Mach nozzle so that the variable Mach nozzle and the combustion heater shut down in response to the shutdown signal; When the variable Mach nozzle and the combustion heater have been shut down, a shutdown signal is sent to the low-pressure exhaust system so that the low-pressure exhaust system shuts down in response to the shutdown signal. Once the low-pressure exhaust system has been shut down, a shutdown signal is sent to all cooling systems.

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