The Automotive Wind Tunnel Contraction Section Design And The Flow Field Quality Analysis Based On CFD

In recent years, with the improvement of our country’s automotive R&Dcapabilities，vehicle aerodynamics design in the entire process of Automotive R&Dgets more and more attention. As the major mean of vehicle aerodynamics research,the car wind tunnel test in the development of new models has been widely used.Under this background, groups of wind tunnels began to be built. But from the theoryof wind-tunnel construction we know that, the flow field quality of wind tunnel candirectly affect the accuracy and stability of wind tunnel test results. So the flow fieldquality has always been the issue to be considered in the process of wind tunnel designand construction. The previous practices are usually estimated based on experiencebefore the construction or test measured when the project is finished. Often there issome deviation or a certain lag. Therefore, in this paper CFD method is adopted todesign the contraction section and analyze the flow field quality of the two vehicle testsection, provides reference for automotive wind tunnel to carry out more aerodynamicresearch.Based on the above analysis, the following works have been done in this paper:Firstly, based on the type, application, test section size, the maximum wind speed,flow field quality and other factors of wind tunnel，the general layout scheme and somedetails of the wind tunnel have been finished in this paper.Secondly, taking into account that the contraction section is an importantcomponent of the wind tunnel, and it plays a vital role in improving the air quality ofthe test section, in this paper, according to the design size of wind tunnel contractionsection, compares and analyzes three typical design curves of the contraction section,finally determines the optimal design curve fiting for this wind tunnel contractionsection by checking their separation characteristics and velocity uniformity.Lastly, the CAD model of the wind tunnel is established in accordance with1:1ratio, and a detailed analysis and evaluation of the flow field quality of the real vehicletest section and scaling model test section is carried out, and then uses the internationalstandard model MIRA to verify the flow field quality of this wind tunnel. The resultsshow that: the wind tunnel design is successful.The research results indicate that: CFD can be used to design some parts of thewind tunnel and analyze the wind tunnel flow field quality. It is of great significance in the wind tunnel design stage.