Development of Aerodynamic Design of Hypersonic Quiet Nozzles

AbstractThe hypersonic quiet nozzle has to be carefully designed by the aerodynamic techniques to obtain the quiet-flow test region with low noise levels comparable to flight. Two conceptual aerodynamic techniques tolaminarizethe nozzle wall boundary layer in the past quiet nozzle design, such as the use of the slower expansion nozzle and the bleed slot in the subsonic region upstream of the throat, are summarized. For the design of the expansion contour of quiet nozzles, the analysis based on the favorable pressure gradient effect is performed and relative results seem to be helpful to theoretically understand the quiet nozzle's evolution from rapid expansion to slow expansion. On the other hand, the bleed slot for the suction of the subsonic boundary layer in the contraction is also required to be analyzed in details. The distance from lip to throat and the maximum width of bleed slot could affect the suction of the slot to the boundary layer by changing the separation location and would be also analyzed