Two dimensional blow-down type supersonic wind tunnel was designed and fabricated. And its performance test with emphasis on the transient behavior was measured in this study. Due to the limiting factors such as reservoir tank size, maximum tank pressure and piping, and determined factors such as area ratio and running time, the test section of the wind tunnel is 2.5cm wide and 6cm high with throat of 2.5cm×2cm square cross section. An MOC calculation was carried out to determine the contour of diverging part of the nozzle from throat to test section. Converging part of the nozzle upstream the throat was contoured to make the flow profile at the throat uniform.
For visualization schlieren photography was used, and it was used also for testing the steady performance of the wind tunnel, Mach number was evaluated from the oblique shock angle on a sharp wedge with half angle of 5 degree, and in result Mach number was 2.4. For initial transient measurements, the sharp wedge was inserted in the wind tunnel and high speed digital motion picture was taken with schlieren technique. With the pictures, the time from the wind tunnel operating to building up supersonic flow in the test section was analogized about 0.1 second. This study will be an important parameter to design of chemical laser system.
