Experimental Investigations of a Diffuser Start/Unstart Characteristics for Two Stream Supersonic Wind Tunnel
The present paper aims to clarify the starting characteristics of two stream diffusers. Two types of diffusers are examined for a two-stream supersonic wind tunnel: constant area and C-D diffuser. Experiments are conducted at five different secondary Mach numbers (1.8–2.6) by keeping primary at constant Mach number2. High-speed schlieren and pressure measurements are used to understand the performance of the diffuser. This study reveals encouraging results in performance of this tunnel with optimum diffuser geometry. This work also highlights the visualized unsteady complex flow fields with significant boundary layer separation during the transient period for a different Mach number and diffuser conditions. Hysteresis is apparent in a transient process of start/unstart of a tunnel; it is used to decrease the operating starting pressure of the tunnel.
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