Rapid method for contour design of linear plug nozzle

To develop a rapid and efficient method for contour design of linear plug nozzle, the obliquity of internal nozzle and the expansion ratios of plug nozzle and internal nozzle, which are related to the expansion capability, were theoretically analyzed. Two second-degree polynomials and a third-degree polynomial were adopt to describe the contours of a linear plug nozzle, and the means in determining nozzle contours were also presented. The influence of the plug nozzle expansion ratios on its figure dimensions was studied. Two types of plug nozzles designed by the rapid method were tested with cold flow, and the experimental results demonstrate the excellent altitude compensating capability.