减弱喷管侧向力的变形喷管技术研究

In order to ameliorate the side load problem of the large area ratio overexpansion nozzle and improve the overall performance of the rocket engine nozzle, a technique scheme of morphing nozzle was proposed to reduce the side loads. Taking the expansion section of VOLVO-S1 nozzle wall as the basic research model, the cross-section of the nozzle wall in the X-axis direction was changed from circular to elliptical by applying a pair of symmetrical forces in the Y-axis direction. The area ratio of the nozzle and the flow path characteristics were changed so that the goal of reducing the side loads can be achieved. By using the numerical method for solving the Reynolds averaged N-S equation, the corresponding changes in the flow field of the morphing nozzle were carried out. The results show that after exerting a certain size force, the nozzle outlet area is reduced by 0.98%, the peak of side loads of morphing nozzle in the Y direction can be reduced to 60% of the original with a small thrust loss, at the same time, the side loads in the Z direction can be nearly made down to half of the original nozzle. Additionally, the transformation from freedom shock separation to restricted shock separation occurs at nozzle pressure ratio being 15.2~15.3 in the morphing nozzle, which is delayed compared to the shock mode transition of the VOLVO-S1 nozzle. Finally, the reason why the side loads are reduced in the morphing nozzle is analyzed.