Operation method of large-blocking-degree fan tester in continuous wind tunnel

Abstract

The invention discloses an operation method of a large-blocking-degree fan tester in a continuous wind tunnel, relates to the technical field of wind tunnel tests, reduces the damage risk of the large-blocking-degree and high-rotating-speed fan tester to a wind tunnel compressor, and comprises the following steps: firstly, starting the compressor to be in an idling state of thirty revolutions per minute to form a mechanical barrier; damage to the mechanism caused by driving the static compressor when the tester fan starts at high speed is avoided; and controlling the total pressure of the wind tunnel to gradually increase the rotating speed of the fan to a target value, stably operating for one minute to verify equipment, eliminating step interference, finally performing closed-loop regulation on the rotating speed of the compressor, calculating a real-time Mach number based on a test section nozzle static pressure measured value, controlling the airflow Mach number deviation to be within a five-ten-thousandth absolute value, and controlling the total pressure fluctuation to be less than one thousandth. The operation limitation of a traditional wind tunnel on a large-blocking-degree fan is broken through, the process of a high-rotating-speed fan tester in a continuous wind tunnel is standardized, and a wind tunnel test task can be safely and reliably carried out with high quality and high efficiency.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology, and specifically to a method for operating a high-obstruction fan tester in a continuous wind tunnel. Background Technology

[0002] A continuous wind tunnel is a tubular test facility used to simulate gas flow around an aircraft or object. It is a key experimental facility supporting aircraft engineering development, evaluation, and fundamental and cutting-edge research in aerodynamics. It artificially generates and controls airflow to simulate gas flow around an aircraft model, measure the effects of the airflow on the model, and observe physical phenomena. Continuous wind tunnels typically use compressors (fans) for energy. Stable airflow conditions are established by real-time measurement of the total pressure in the stable section ahead of the test section and the static pressure of the test section, and by real-time control and adjustment of the compressor speed or the opening of the gas tank valves.

[0003] Advanced engines require high-performance air intakes to form a high-performance power plant. Wind tunnel air intake testing is a crucial part of aircraft design. Air intake testing includes both static and dynamic tests, aiming to measure static and dynamic characteristics and provide experimental data for air intake design. The tests involve numerous parameters, primarily measuring and calculating the air intake's total pressure recovery coefficient, flow rate coefficient, outlet steady-state distortion, outlet dynamic distortion, and matching point performance parameters under various flight conditions.

[0004] In typical continuous wind tunnel inlet tests, the experimental setup does not contain a high-speed fan. Therefore, there is no need to consider the risk of damage to the wind tunnel compressor or interference with the accurate establishment of the wind tunnel flow field caused by the fan's high-speed rotation. In this type of test, the wind tunnel operation mode involves the main control system presetting the states of the wind tunnel's moving sections, providing the test parameters to the supporting systems, and then starting the compressor at low speed to bring the wind tunnel to the required total pressure for the test. Then, the main compressor speed is controlled to reach the test Mach number. M And perform closed-loop adjustment to achieve the experimental Mach number. M Wind tunnel total pressure Once the flow field stabilizes within the error band, all systems begin collecting experimental data.

[0005] In wind tunnel testing, generally speaking, the wind tunnel blockage of the model should not exceed 5% in order to obtain accurate aerodynamic measurement results. On the other hand, in order to achieve physical similarity to the real shape, especially the Reynolds number, the size of the aerodynamic noise measurement model needs to be as large as possible, which contradicts the blockage requirement. Moreover, large blockage experimental devices (blockage exceeding 5%) have a certain interference effect on the accurate establishment of the wind tunnel flow field.

[0006] The high-speed fan experimental setup simulates the shape of an aircraft engine air intake and is equipped with a high-speed rotating fan. The effects of the high-speed rotating fan on continuous wind tunnel testing are as follows: (1) When the continuous wind tunnel compressor is stationary, the wind force generated by the high-speed fan will drive the wind tunnel compressor to start rotating, which will damage the compressor's locking mechanism. (2) During the experiment, the flow field generated by the high-speed fan will also interfere with the correct establishment of the wind tunnel flow field. Summary of the Invention

[0007] To address the problem of damage to wind tunnel compressors caused by high-obstruction, high-speed fan testers, and to resolve the interference caused by these testers, which prevents accurate establishment of the wind tunnel flow field, this invention provides a pioneering method for operating a high-obstruction fan tester in a continuous wind tunnel. This method standardizes the testing process for high-speed fan testers in continuous wind tunnels, enabling high-quality, efficient, safe, and reliable conduct of similar wind tunnel tests.

[0008] The technical solution of this invention includes: S1: Install the high-speed fan tester with a blockage of more than 5% in the wind tunnel test section through wall support, connect the test equipment and verify that it is working properly; S2: Start the wind tunnel main compressor to idle speed; S3: Controlling the total pressure of the wind tunnel via a medium-pressure air supply system and heat exchanger. Total temperature in the stable section The preset temperature is 20℃~25℃; S4: Gradually increase the speed of the high-speed fan tester to the target speed and run it stably for 1 minute; S5: Closed-loop regulation of the main compressor speed to achieve the test Mach number. M With target value deviation ΔM ≤±0.001, total wind tunnel pressure Control accuracy ≤ 0.1%, data collected after establishing a stable flow field; S6: Repeat steps S4-S5 until the experiment is completed.

[0009] Furthermore, in S5, the experimental Mach number M pass: Obtain, among which, P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section; Experimental Mach Number M With target value deviation ΔM pass: get.

[0010] The beneficial effects of this invention are as follows: This invention solves the problems of damage to the compression mechanism and flow field interference caused by high-speed fans in wind tunnel tests with high blockage by precisely controlling the pre-start compressor idling speed and closed-loop flow field. Attached Figure Description

[0011] Figure 1 This is a flowchart of the operation method of a high-obstruction fan experimental device in a continuous wind tunnel according to the present invention;

[0012] Figure 2 The actual total pressure of the wind tunnel during the test. The curve shows the change over time. The target total pressure in the wind tunnel is 31435 Pa. As can be seen from the curve, the actual total pressure control accuracy is ≤0.1%.

[0013] Figure 3 The actual Mach number of the wind tunnel during the test. M Curve of change over time, wind tunnel target Mach number The value is 0.5. As can be seen from the curve, the actual Mach number is... M With target value deviation ΔM ≤±0.001. Detailed Implementation

[0014] The technical solution of the present invention will be further described below with reference to embodiments, but it is not limited thereto. Any modifications or equivalent substitutions to the technical solution of the present invention without departing from the spirit and scope of the technical solution of the present invention should be covered within the protection scope of the present invention. In the following embodiments, the process equipment or apparatus not specifically specified are all conventional equipment or apparatus in the art. Unless otherwise specified, the raw materials used in the embodiments of the present invention are all commercially available; unless otherwise specified, the technical means used in the embodiments of the present invention are all conventional means well known to those skilled in the art.

[0015] Example 1, combined with Figure 1 This embodiment describes a method for operating a high-obstruction fan experimental device in a continuous wind tunnel, comprising:

[0016] S1: Install the high-speed fan tester with a blockage of more than 5% in the wind tunnel test section through wall support, connect the test equipment and verify that the balance, scanning valve and other test equipment as well as the data acquisition equipment are working properly; S2: Start the wind tunnel main compressor to idle speed; S3: Controlling the total pressure of the wind tunnel via a medium-pressure air supply system and heat exchanger. Total temperature in the stable section The preset temperature is 20℃~25℃; S4: After each mechanism of the model reaches the predetermined working condition position, gradually increase the speed of the high-speed fan experimental device to the target speed and run stably for 1 minute; S5: Closed-loop regulation of the main compressor speed to achieve the test Mach number. M With target value deviation ΔM ≤±0.001, total wind tunnel pressure With a control accuracy of ≤0.1%, after the flow field is stable and the configuration is in place, the aerodynamic force on the model is measured by a dedicated balance. The measurement results are collected by a dedicated data acquisition system and transmitted to the server for calculation and processing to complete the measurement of the aerodynamic force of the experimental model. The pressure data on the model surface is obtained by collecting data from the scanning valve through the pressure acquisition system. After continuous acquisition for 8 seconds, the speed of the experimental apparatus is controlled to change to the next working condition. S6: Repeat steps S4-S5 until the experiment is completed.

[0017] Specifically, Figure 2 , Figure 3 This clearly demonstrates that the wind tunnel flow field was accurately established during the test, and the flow field quality was uniform and stable.

[0018] In S5, the experimental Mach number M pass: Obtain, among which, P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section; Experimental Mach Number M With target value deviation ΔM pass: get.

Claims

1. A method for operating a high-obstruction fan experimental device in a continuous wind tunnel, characterized in that, include: S1: Install the high-speed fan tester with a blockage of more than 5% in the wind tunnel test section through wall support, connect the test equipment and verify that it is working properly; S2: Start the wind tunnel main compressor to idle speed; S3: Controlling the total pressure of the wind tunnel via a medium-pressure air supply system and heat exchanger. Total temperature in the stable section The preset temperature is 20℃~25℃; S4: Gradually increase the speed of the high-speed fan tester to the target speed and run it stably for 1 minute; S5: Closed-loop regulation of the main compressor speed to achieve the test Mach number. M With target value deviation ΔM ≤±0.001, total wind tunnel pressure Control accuracy ≤ 0.1%, data collected after establishing a stable flow field; S6: Repeat steps S4-S5 until the experiment is completed.

2. The method for operating a high-obstruction fan experimental device in a continuous wind tunnel according to claim 1. Its features are, In S5, the experimental Mach number M pass: Obtain, among which, P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section; Experimental Mach Number M With target value deviation ΔM pass: get.

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