Abstract
Development of a supersonic nozzle with a rectangular cross section for a scramjet model combustor was performed and verified experimentally and numerically. The newly-proposed combined design methodology is easier to use than the other design methodologies when the nozzle exit geometry is the constraint condition because it can get information about the displacement thickness before determining the supersonic nozzle contour. The velocity profile of the numerical simulation and that of LDV measurements are quantitatively in good agreement, which meant that the numerical simulations performed in the present study could quantitatively evaluate the flowfield in the supersonic nozzle and the isolator developed in the present study. The designed supersonic nozzle showed good uniformity of the Mach number and stream angle in the mainstream region at the nozzle exit. Also, the average Mach number in the mainstream region at the nozzle exit plane showed very good agreement with the design Mach number. The influence of airstream total temperature on the Mach number distribution and stream angle distribution in the mainstream region was investigated numerically and was acceptably small, which means that the supersonic nozzle designed in this study can create approximately equivalent supersonic flow in the range of airstream total temperature 300 K - 800 K. Additionally, The mainstream region was found to have a trapezoidal shape with the upper side as the short side and the lower side as the long side. This trapezoidal shape is considered to be caused by the pressure gradient along the side wall, indicating that it is difficult to prevent the mainstream region from growing to trapezoidal shape in case of two dimensional supersonic nozzle with a single contour wall.
