Design and Installation of Supersonic Free Jet Test Facility with Flow Visualization

Abstract

A supersonic free jet test facility has been designed and a flow visualization equipment has been installed in order to analyze the flow characteristics of a jet emanating from nozzles. The free jet facility has two storage tanks of 14 m3 and 7 m3 capacity, since it has been designed to carry a maximum pressure of 30 bar. The proper design of the plumbing system has been carried out to transfer the compressed air from the storage tank to the settling chamber. The high-pressure pipes and the control valves have been used to control the compressed air flow to the settling chamber. The nozzle is fixed at the end of the settling chamber through a threaded joint so that nozzles with different profiles can be easily fitted. A pressure gauge is attached to the settling chamber to measure the pressure and the flow is controlled by a globe valve. A vertical z–type Schlieren apparatus has been designed to capture the flow pattern of the jet emerging from different nozzle configurations, which consist of a monochromatic light source, mirrors, knife-edge, and a high-speed camera. The experimental set-up has been installed successfully and clear Schlieren images have been captured from subsonic, under-expanded, and supersonic jet flows. The free jet facility can operate efficiently up to a Mach number of 2.75 with a supersonic nozzle throat diameter of 20 mm.