Research On The Overall Structure Of Subsonic And Low Density Wind Tunnel

Combined with the research status of subsonic and low density wind tunnels at home and abroad,this thesis proposes the requirement of constructing subsonic and low density wind tunnel,aiming at designing a pilot wind tunnel for the subsonic and low density Mars wind tunnel,to provide experimental conditions for the development of new Mars probe.Based on the analysis of test requirements,the main technical parameters of the wind tunnel such as the size of test section,the Reynolds number,the Mach number,the pressure and density conditions were determined.According to the abovementioned technical parameters,the thesis focused on the design of aerodynamic performance and key components.The main research works are as follows.Selection of the driving type for the subsonic and low density wind tunnel.To solve the special aerodynamic problems under low pressure and low density conditions,we put forward a DC injection type wind tunnel structure,which could be placed in a low pressure and low density environmental simulation cabin with the employ of the ejector driving type scheme.Calculation of aerodynamic performance on the subsonic and low density wind tunnel.The key components of the wind tunnel include: settling section,contraction section,test section,first diffusion section,mixing section,and second diffusion section,etc.According to the calculation results of aerodynamic performance,the sizes of all key components were obtained.The airflow parameters of the ejector device were calculated in detail,and a reasonable ejection scheme was obtained.Analysis of flow field characteristics of subsonic and low density wind tunnel.By using computational fluid dynamics(CFD)method,the characteristics of the contraction curve of the wind tunnel contraction section and the eject performance of the ejector were simulated and analyzed.The simulation results show that the ejector driving scheme is feasible under the low pressure condition,namely the wind tunnel reaches the design requirements of providing flow conditions for the detector test.