PERFORMANCE VARIATION OF SCRAMJET NOZZLE AT VARIOUS NOZZLE PRESSURE RATIOS

An experimental study of scramjet nozzle was conducted to investigate how the nozzle now is affected by ambient pressure. In order to elucid ate the aerodynamic properties of nozzle flow, detailed measurements o f thrust and wall pressure were carried out using cold nitrogen. Nozzl e now was also visualized using a shear sensitive liquid crystal. Wall pressure and shear stress distributions in an overexpanded nozzle sho wed that nozzle flow includes a crossing shock wave made at the side-f ences. This flowfield can be approximated as a supersonic inlet now co mpressed by sidewalls. The high-pressure region on the nozzle ramp gen erated by the shock waves results in a higher performance in scramjet nozzle than that estimated for a two-dimensional separation from the r amp.