Low Speed Wind Tunnel Data Acquisition And Control System Developed

Wind tunnels are essential for research and teaching of aerodynamics; they provide a major means for discovering and confirming airflow phenomena, exploring and revealing airflow mechanism, seeking and understanding airflow rules, and providing fine aerodynamic configuration and aerodynamic characteristic data for aircraft design. The development of advanced wind tunnel is the prerequisite fortenhancing accuracy and standard of wind tunnel experiments, playing an important role in improving product aerodynamic design.This thesis first puts forward a general plan for data acquisition and processing and for closed-loop control of wind speed, and based on this carries out the hardware and software design. The hardware of the system includes three-phase asynchronous motor, frequency converter, transducers, signal regulators, data acquisition card, industrial control device, and special equipment for wind tunnel measurement, etc.; the software of the system is developed on the LabVIEW6.1 platform of American NI Company. Using the system designed in this thesis work, flow field calibration of the wind tunnel is accomplished, which covers dynamic pressure drop coefficient, dynamic pressure time stability, axial static pressure gradient, boundary layer, and degree of turbulence, etc. Boundary layer measuring principle and method are especially described in detail, the relationship between boundary layer thickness, wind speed setting, and the depth of the experimental section is summarized, and finally the calibration data for the model center zone under specific wind speed are given.The wind tunnel data acquisition and processing system designed by this thesis work has passed the shakedown test, and utilizing this system several wind tunnel experiments have been conducted successfully, including an unmanned airplane model and a glider model. Accurate experimental data and valuable experimental conclusions are obtained. Practical applications show that this data acquisition and processing system fully satisfies the design requirements, demonstrating very high practicality and character of advancement.