Effect of fuel grain configuration on the thrust of a solid-fuel scramjet

The thrust of a solid-fuel scramjet rapidly decreases during the combustion process, limiting its application in hypersonic aircrafts. The purpose of this study was to alleviate this problem by optimizing the structure of the fuel grain. A 2D axisymmetric model was established to investigate the internal flow structure of the combustion chamber. Two types of fuel grain structures were proposed to reduce the thrust drop of the solid-fuel scramjet. A series of experiments were conducted to verify the correctness of the numerical model and the effectiveness of the fuel grain structures in suppressing the thrust drop. The results showed that the new fuel grain structures of the solid-fuel scramjet can slow down the total pressure loss in the combustion chamber and thereby suppress the thrust reduction.