PERFORMANCE EVALUATION OF VARIOUS CONTROL STRATEGIES FOR HYPERSONIC WIND TUNNEL

Wind tunnel is a facility used to investigate the aerodynamic properties of objects by passing a stream of velocity-controlled air over them. They are an excellent example of a technological innovation that supports aircraft design. The hypersonic wind tunnel can hit the hypersonic speeds necessary to test the latest ultra fast aircraft and space planes. The wind tunnel allows us to make a reusable prototype and test it in the tunnel. Although the form of a wind tunnel can vary, all wind tunnels have a high pressure system, heater, settling chamber and a test section. Air is compressed and stored in the high pressure system. It is released through a pressure regulating valve to create the desired pressure in the settling chamber. Heater is used to heat the air while passing through the heater bed to avoid liquefaction when it is expanded through the nozzle to get high Mach numbers. The pressure in the settling chamber is controlled by the proper operation of the control valve so that flow through test section meets the Mach number and mass flow rate specified for the test conditions. The set pressure has to be reached within few seconds since the system/process exists for very short duration. So it is a challenging task to develop a controller that should adapt for different set pressure values as per the requirement, inlet