Aerodynamic design of 2.4 m continuous transonic wind tunnel

Driven by axial flow compressor, the continuous transonic wind tunnel has the advantages of wide operating range, high flow field quality and long running time, and is the most important type of transonic wind tunnel in the world. In recent years, the test demand of large continuous transonic wind tunnels for the aircraft development in China is growing rapidly, therefore, the AVIC Aerodynamics Research Institute (AVICARI) built the first continuous transonic wind tunnel of China, i.e. the 2.4 m continuous transonic wind tunnel. In order to obtain the best flow field quality and aerodynamic performance of the wind tunnel, AVICARI has developed a number of aerodynamic design techniques applicable to continuous transonic wind tunnels, including design methods for high-speed sections, such as the nozzle, the test section, the second throat, as well as techniques for the low-speed sections. In this paper, both the overall design requirement and the aerodynamic design methods of some main sections suitable for continuous transonic wind tunnels are introduced in detail, which are studied and verified by CFD and wind tunnel tests. Through the application of these aerodynamic design techniques, the flow field uniformity, noise level and turbulence intensity of the 2.4 m continuous transonic wind tunnel have reached the international advanced level, with the test data in good consistency with those from similar wind tunnels abroad.