Experimental research on collector effect on operating characteristics of high-speed free-jet wind tunnel

Collector is one of the key parts of the high-speed free-jet wind tunnel, which directly affects the performance of wind tunnel. In this paper, a small high-speed free-jet wind tunnel is used as the test platform to carry out the start-up and operation characteristics test of wind tunnel. Start-up pressure characteristics were obtained at various Mach number, and the influence of the collector throat heights and collector positions on start-up pressure and matching pressure was preliminarily studied. The results show that the high collector throat height can meet the requirements of wind tunnel start-up and pressure matching. The closer the collector is to the nozzle, the smaller the corresponding starting pressure and matching pressure. However, this trend weakens with the decrease of Mach number, which lays a foundation for the development of large high-speed free jet equipment.