助推器侧向卸压喷流对尾舵气动干扰的数值研究

Numerical investigation into aerodynamic interference exerted on tail rudders by booster thrust ceasing jets

关键词:  级间分离  火箭发动机  侧向喷流+  数值仿真  非定常流

Key words:  Stage separation  Rocket engine  Lateral jet+  Numerical simulation  Unsteady flow

摘要:

采用燃气/空气双组元冻结流模型,基于任意多块对接结构网格求解三维N-S方程,数值分析了导弹助推器分离前侧向卸压喷流对尾舵气动力的干扰特性。得到了助推器推力终止侧向卸压过程中,喷流与外流干扰的非定常流场结构以及尾舵气动力的变化历程。分析结果表明,卸压开始后的一段时间内尾舵受到卸压喷流的屏蔽作用,尾舵气动力不能提供足够的分离冲量,此时对其进行舵偏控制将是无效的,尾舵控制时序应该自卸压开始延迟180 ms。

Abstract:

Numerical analysis was carried out about the interference to the aerodynamic forces of tail rudders of a missile caused by lateral jets during its booster thrust ceasing process.3D unsteady N-S equations with two species of jet gas and air frozen flow model were considered and solved based on structured multi-block patching meshes using finite difference method.The unsteady interfering characteristics of main external flow and thrust ceasing jets were obtained as well as the variation history of aerodynamic forces of tail rudders involved in such interfering flow field.It is observed from the results that the tail rudders are shrouded in the wake of lateral jets during the early period of the booster combustion chamber decompressing,and,in this period the aerodynamic forces of tail rudders can not provide adequate drag to accomplish booster separation process,the tail rudders deflecting control should be delayed from the beginning of chamber decompressing for nearly 180 ms.