Infrared test state point parameter adjustment method

Abstract

The application belongs to the technical field of aero-engines, and particularly relates to an infrared test state point parameter adjustment method, including a maximum continuous state point parameter adjustment method, steps of which comprise: determining an engine maximum continuous state point rotating speed range; adjusting an engine control law, so that the engine has a target value of nozzle area in the rotating speed range of the maximum continuous state point; starting the engine; pushing an oil gate lever to a lower limit value of the maximum continuous rotating speed range, and then pushing the oil gate lever to a target value of exhaust temperature and performing infrared measurement. The intermediate state point parameter adjustment method, steps of which comprise: adjusting the engine control law, including: adjusting a limit value of the exhaust temperature to a target value, adjusting limit values of a low-pressure rotating speed and a high-pressure rotating speed to upper limits of an adjustable range, and adjusting a pre-closed loop nozzle area to a target value; starting the engine and pushing the oil gate lever to a pre-closed loop state, the nozzle area being the target value, and performing infrared measurement after the state is stable.

Description

Technical Field

[0001] This application belongs to the field of aero-engine technology, and specifically relates to a method for adjusting infrared test state point parameters. Background Technology

[0002] The infrared test states are specified as the maximum state, intermediate state, and maximum continuous state. However, the afterburner is engaged in the maximum state, and no requirements are made on infrared radiation when the afterburner is engaged in actual flight. Therefore, the intermediate state and the maximum continuous state are the key test states for the infrared test.

[0003] According to the Stefan-Boltzmann law, the higher the temperature of an object, the more energy it radiates. The formula is:

[0004] E=σεT 4

[0005] Where: E—the total infrared radiation energy per unit area and per unit time of an object at temperature T;

[0006] σ -- Stefan-Boltzmann constant;

[0007] ε—specific emissivity;

[0008] T — the absolute temperature of the object.

[0009] Infrared testing mainly targets the nozzle. Therefore, the parameters affecting the infrared radiation intensity are the absolute temperature of the nozzle under test, the nozzle area, and the emissivity of the nozzle material. Since the nozzle material remains unchanged and the emissivity is a constant, the main parameters affecting infrared testing are the nozzle area and the engine exhaust temperature.

[0010] To characterize the infrared radiation intensity of the engine, tests need to be conducted under the same exhaust temperature and nozzle area. However, due to the influence of the control law, there are differences in nozzle area and exhaust temperature between the maximum continuous state and the intermediate state. Therefore, the test needs to be adjusted multiple times until the two parameters are close to the target value. Subsequently, the data is fitted to the target value, but the data fitting seriously affects the accuracy of infrared measurement.

[0011] Based on the above situation, there is an urgent need to design an efficient and convenient method that can ensure that the exhaust temperature and nozzle area of ​​the engine are both at the target values ​​in both the maximum continuous state and the intermediate state.

[0012] Currently, domestic infrared testing typically involves collecting data after the exhaust temperature and nozzle area have approached the target values. This method severely impacts the accuracy of infrared test results and is cumbersome, time-consuming, and expensive, specifically manifesting in the following aspects:

[0013] The engine needs to be adjusted multiple times to ensure that the exhaust temperature and nozzle area are close to the target values.

[0014] Multiple trials and adjustments led to increased costs for oil, gas, water, and electricity.

[0015] Data processing and analysis require fitting calculations, which increases the workload.

[0016] Fitting calculations severely affect the accuracy of infrared test results;

[0017] Multiple debugging sessions and data fitting significantly impacted experimental efficiency.

[0018] In summary, this method is time-consuming, expensive, and cumbersome, which seriously affects the progress of experiments and research and development. Summary of the Invention

[0019] To address the aforementioned problems, this application provides a method for adjusting infrared test state point parameters.

[0020] This includes a method for adjusting the parameters of the maximum continuous state points, with the following steps:

[0021] Determine the maximum continuous state point speed range of the engine;

[0022] Adjust the engine control law so that the nozzle area is the target value within the engine speed range of the maximum continuous state point;

[0023] Start the engine and allow it to warm up completely;

[0024] Push the throttle lever up to the lower limit of the maximum continuous speed range, then push the throttle lever up until the exhaust temperature reaches the target value and remains there, and start infrared measurement in a steady state.

[0025] Preferably, it also includes an intermediate state point parameter adjustment method, the steps of which include:

[0026] Adjust the engine control law, including: adjusting the exhaust temperature limit to the target value, adjusting the low-pressure speed and high-pressure speed limit to the upper limit of the adjustable range, and adjusting the closed-loop front nozzle area to the target value;

[0027] Start the engine and allow it to warm up completely;

[0028] Push the throttle lever up to the pre-closed-loop state. At this time, the engine limits the exhaust temperature, i.e., the exhaust temperature value is the target value, and the nozzle area is the target value. After the state stabilizes, infrared measurement is performed.

[0029] Preferably, after pushing the throttle lever up until the exhaust temperature reaches the target value, hold it for 4 minutes to allow the engine to stabilize. At this point, make a fine adjustment to the throttle lever to ensure that the exhaust temperature equals the target value for a period of time.

[0030] Preferably, infrared measurement is started after ensuring that the exhaust temperature is equal to the target value for at least 1 minute.

[0031] Preferably, the exhaust temperature and nozzle area are set as target values, and infrared measurements are performed after the conditions have stabilized for 4 minutes.

[0032] This application adjusts engine parameters before testing, and can meet the target values ​​of exhaust temperature and nozzle area without experimental verification.

[0033] This avoids the need for multiple trials, adjustments, and verifications, saving on the cost of resources such as oil, gas, water, and electricity.

[0034] This method can greatly improve the accuracy of infrared test results;

[0035] This greatly improves the efficiency of the experiment. Attached Figure Description

[0036] Figure 1 This is the flowchart of the infrared testing experiment for this scheme;

[0037] Figure 2 This is the existing technology for controlling the nozzle area in infrared testing.

[0038] Figure 3 This invention relates to the control law of the infrared test nozzle area. Detailed Implementation

[0039] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions in the embodiments of this application will be described in more detail below with reference to the accompanying drawings. In the drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The described embodiments are only some, not all, of the embodiments of this application. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this application, and should not be construed as limiting this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application without inventive effort are within the scope of protection of this application. The embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0040] A method for adjusting infrared test status point parameters is as follows:

[0041] The methods for adjusting the maximum continuous exhaust temperature and nozzle area are as follows:

[0042] The engine's maximum continuous operating speed has a certain range requirement. Within the required range, the nozzle area in the control plan is adjusted to the target value, that is, the nozzle area is a constant value within the maximum continuous operating speed requirement range.

[0043] Start the engine and allow it to warm up completely;

[0044] Push the throttle lever up to the lower limit of the maximum continuous speed range, then slowly push the throttle lever up until the exhaust temperature reaches the target value. After 4 minutes, the engine condition is basically stable. At this point, make a fine adjustment to the throttle lever to ensure that the exhaust temperature is equal to the target value. After 1 minute, start infrared measurement.

[0045] The principle behind adjusting exhaust temperature and nozzle area at the intermediate state point is as follows: The engine control system typically sets limit values ​​for three parameters: low-pressure speed, high-pressure speed, and exhaust temperature. When any of these three parameters reaches its limit, the engine stops supplying fuel before pushing the throttle lever to the intermediate state to prevent over-revving and overheating. The limit values ​​can be adjusted within a certain range, with the upper limit being the engine's tolerable speed and exhaust temperature. The engine's intermediate state uses closed-loop control, meaning the nozzle area changes with the exhaust pressure. Since the nozzle area is not constant, it significantly impacts infrared testing. Therefore, a simulated intermediate state is used for parameter adjustment to ensure that the exhaust temperature and nozzle area remain constant before the closed-loop control is implemented.

[0046] The methods for adjusting the exhaust temperature and nozzle area at the intermediate point are as follows:

[0047] Adjust the exhaust temperature limit to the target value, and adjust the low-pressure speed and high-pressure speed limits to the upper limit of the adjustable range. This method ensures that the engine exhaust temperature limit is reached first. Adjust the closed-loop front nozzle area to the target value.

[0048] Start the engine and allow it to warm up completely;

[0049] Push the throttle lever up to the closed-loop state. At this time, the engine exhaust temperature is limited to the target value, and the nozzle area is the target value. After the state is stable for 4 minutes, infrared measurement is performed.

[0050] 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 technical scope 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 method for adjusting parameters of an infrared test state point, characterized in that, The method for adjusting the parameters of the maximum continuous state point includes the following steps: determining the engine's maximum continuous state point speed range; adjusting the engine control law so that the nozzle area is the target value within the engine's maximum continuous state point speed range; starting the engine and allowing it to warm up fully; pushing the throttle lever up to the lower limit of the maximum continuous state point speed range, then pushing the throttle lever up until the exhaust temperature reaches the target value and maintaining it, and starting infrared measurement in a steady state. It also includes a method for adjusting intermediate state point parameters. The steps include: adjusting the engine control law, including: adjusting the exhaust temperature limit to the target value, adjusting the low-pressure speed and high-pressure speed limit to the upper limit of the adjustable range, and adjusting the pre-closed-loop nozzle area to the target value; starting the engine and allowing it to warm up fully; pushing the throttle lever to the pre-closed-loop state, at which point the engine limits the exhaust temperature, i.e., the exhaust temperature value and the nozzle area are the target values, and infrared measurement is performed after the state stabilizes; after pushing the throttle lever to the point where the exhaust temperature reaches the target value, maintaining this position for 4 minutes to allow the engine state to stabilize, and then fine-tuning the throttle lever to ensure that the exhaust temperature equals the target value for a period of time.

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