Multiobjective Optimization of Scramjet Strut Geometry Using Computational Fluid Dynamics Approach

Abstract

The purpose of this paper is to discuss a study aiming to optimize the performance of a DLR-type scramjet engine using computational fluid dynamics (CFD). For this purpose, the response surfaces technique is employed to carry out a multi-objective optimization of the strut geometry used in this engine. In the simulation, strut length and width are considered as design variables. Thrust and combustion efficiency are also constituted as objective parameters. Response surfaces are created using two methods: Kriging and nonparametric regression (NPR). The obtained results indicate a higher accuracy of the Kriging approach. The optimization results show that in the best case the amount of thrust can be increased up to 62.618 N, which is 5.6% more than the base value. Also, the combustion efficiency can be raised to a maximum value of 74.4%, which is 12.37% higher than the base value. In order to determine which design variables have a more significant effect on objective factors, sensitivity analysis has been performed. This analysis revealed that the strut width has more significant effect on the combustion efficiency, while the thrust was more dependent on the strut length.