逆向喷流对可回收火箭气动特性的影响研究

Effects of opposing jet on aerodynamic characteristics of reusable rocket

关键词:  可回收火箭  低空逆向喷流  高空逆向喷流  气动特性  数值仿真

Key words:  Reusable rocket  Opposing jet under low altitude  Opposing jet under high altitude  Aerodynamic characteristics  Numerical simulation

摘要:

可回收火箭返回时，需要依靠发动机进行点火减速制动，为得到逆向喷流条件下箭体气动性能的变化规律，通过对低空和高空两次点火过程进行数值仿真，分析来流马赫数和攻角对箭体气动性能的影响，同时开展单喷管、多喷管喷流条件下的仿真研究。结果表明，低空状态，逆向喷流会导致全箭轴向力系数绝对值减小，且喷流数目越多，轴向力系数绝对值越小。小攻角条件下，逆向喷流会引起全箭压心大幅前移，随着开机台数增加，压心前移越多。高空条件下，喷流膨胀区和来流存在强烈的相互干扰，导致轴向力系数减小明显，其绝对值在0.04以内，0°~10°攻角内箭体法向力系数绝对值小于0.1，随着来流静压增加，法向力系数绝对值小于0.1的攻角区间减小。

Abstract:

When reusable rocket returns， it needs to rely on engine ignition deceleration. In order to obtain the change rule of aerodynamic performance of the rocket under the condition of opposing jet， the CFD simulation was taken under low altitude and high altitude. The effects of free stream flow Mach number and angle of attack on aerodynamic performance of the rocket were analysed. At the same time the single nozzle and multiple nozzle jets simulations were carried out. The results show that at low altitude， the absolute value of axial force coefficient decreases under opposing jet condition and the axial force coefficient decreases with the increase of the number of jet flow. Under the condition of small angle of attack， the opposing jet caused the pressure center to move forward greatly， and the pressure center moved forward more with the increase of the number of starting engines. Under the condition of high altitude， there was strong mutual interference between jet expansion zone and incoming flow， which resulted in the obvious axial force coefficient decrease. The absolute value of axial force coefficient was within 0.04.The absolute value of normal force coefficient was less than 0.1 within the range of 0°~10° angle of attack. With the increase of static pressure of incoming flow， the range of angle of attack with the absolute value of normal force coefficient less than 0.1 decreased.