Design of Maximum Thrust Nozzle Contours by Direct Optimization Methods

Abstract

A PROCEDURE for the design of maximum thrust nozzle contours by direct optimization methods is presented. The nozzle contour is a second-degree polynomial having a fixed initial expansion contour. The coefficients of the polynomial are varied by direct optimization methods to determine the maximum thrust contour. Three direct optimization methods are considered: multidimensional line search, the method of steepest descent, and Newton's method. Results are presented to illustrate the behavior of the direct optimization methods, and to demonstrate that second-degree polynomial contours yield thrusts comparable to the thrusts developed by nozzle contours determined by calculus of variations methods.