Method for operating a large blockage fan rig in a continuous wind tunnel

Abstract

A method for operating a large blockage fan tester in a continuous wind tunnel relates to the technical field of wind tunnel test, reduces the damage risk of the large blockage, high speed fan tester to the wind tunnel compressor, starts the compressor to thirty revolutions per minute idling state to form a mechanical barrier, avoids the damage of the stationary compressor to the mechanism when the tester fan is started at high speed, controls the total pressure of the wind tunnel to gradually increase the fan speed to the target value, stabilizes the operation for one minute to verify the equipment, eliminates the step disturbance, finally closes the loop to adjust the compressor speed, calculates the real-time Mach number based on the measured value of the test section nozzle static pressure, controls the airflow Mach number deviation within 5 / 10,000 absolute value, and the total pressure fluctuation is less than 1 / 1000. The application breaks through the operation limit of the traditional wind tunnel to the large blockage fan, standardizes the process of the high speed fan tester in the continuous wind tunnel, and can carry out the wind tunnel test task with high quality, high efficiency, safety and reliability.

Description

Technical Field

[0001] This invention relates to the field of wind tunnel testing technology, 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:

[0007] (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.

[0008] (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

[0009] 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.

[0010] The technical solution of this invention includes:

[0011] 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;

[0012] S2: Start the wind tunnel main compressor to idle speed;

[0013] 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℃;

[0014] S4: Gradually increase the speed of the high-speed fan tester to the target speed and run it stably for 1 minute;

[0015] 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;

[0016] S6: Repeat steps S4-S5 until the experiment is completed.

[0017] Furthermore, in S5, the experimental Mach number M pass:

[0018] Obtain, among which,P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section;

[0019] Experimental Mach Number M With target value deviation ΔM pass:

[0020] get.

[0021] 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

[0022] 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;

[0023] 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%.

[0024] 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

[0025] 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.

[0026] 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:

[0027] 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;

[0028] S2: Start the wind tunnel main compressor to idle speed;

[0029] 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℃;

[0030] 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;

[0031] 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.

[0032] S6: Repeat steps S4-S5 until the experiment is completed.

[0033] 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.

[0034] In S5, the experimental Mach number M pass:

[0035] Obtain, among which, P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section;

[0036] Experimental Mach Number M With target value deviation ΔM pass:

[0037] 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: Control the total pressure of the wind tunnel P0 to ≤ 104000Pa and the total temperature T0 of the stable section to the preset value of 20℃~25℃ through the medium-pressure air supply system and heat exchanger; 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 adjustment of the main compressor speed to ensure that the deviation ΔM between the test Mach number M and the target value M0 is ≤ ±0.001 and the control accuracy of the wind tunnel total pressure P0 is ≤ 0.1%, and data is collected after establishing a stable flow field; S6: Repeat steps S4-S5 until the experiment is completed; In S5, the experimental Mach number M is obtained through: ； Obtain, where P W The static pressure value measured by the pressure sensor at the nozzle of the wind tunnel test section; The deviation ΔM between the experimental Mach number M and the target value M0 is achieved through: ； get.

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