Flow field control for 2-meter high-speed free-jet wind tunnel

Abstract

The 2-meter High-speed Free-jet Wind Tunnel (2 m HFWT) is China's first large-scale open-jet trisonic wind tunnel. Compared to traditional closed high-speed wind tunnels, this wind tunnel is endowed with remarkable advantages of ample test chamber space, less interference from the tunnel wall, flexible model support mode, and adjustable continuous variation of the Mach number. Nevertheless, its unique structure makes traditional wind tunnel control methods difficult to apply and brings significant challenges to wind tunnel flow field control. In this paper, a flow field control system is designed for the 2 m HFWT by comprehensively using advanced control technologies such as neural network, gain scheduling, feedforward control, and adaptive control. Through practical application tests, it is proved that the proposed control system successfully solves the problem of high-precision flow field control under continual depletion of storage tank pressure, and realizes distinctive functions of adaptive static pressure matching and continuously varying Mach number at supersonic speed. In addition, due to the application of workflow technology, the flow field control system can flexibly adapt to the implementation of tests of different types and operation conditions, thus fully satisfying the needs of conducting various conventional and special tests in the 2 m HFWT.