【摘要】 为便于火星着陆器抛背罩安全性仿真,针对火星着陆器简化外形开展了背罩分离的定常数值计算,分析了着陆平台与背罩之间的气动效应,获得了着陆平台与背罩的轴向力系数随分离间距的变化规律。结果表明:初始分离瞬间,由于着陆平台嵌入背罩内部,它们之间的压力接近驻点压力,随着分离间距的增加,背罩与着陆平台之间的压力逐渐由接近驻点压力慢慢过渡到接近底部绕流压力,至分离间距为0.1倍大底直径后,背罩一直处于着陆平台的底部绕流区。分离间距为0~0.06倍大底直径时,背罩的轴向力系数大于着陆平台,容易分离;分离间距为0.06~6倍大底直径时,着陆平台的轴向力系数大于背罩,存在分离后重新结合并发生碰撞的危险,且在分离间距为1倍大底直径时,着陆平台与背罩之间由于回流作用而产生的吸力达到峰值,此时发生碰撞的危险系数最大;分离间距超过6倍大底直径后,背罩的轴向力系数再次超越着陆平台,可以确保抛背罩安全分离。更多还原

【Abstract】 The Mars lander back shell separation is numerically calculated for its safety simulation. The aerodynamic effect between the landing platform and back shell is analyzed. And the variation of the landing platform and back shell axial force coefficient with separation distance are gained. The results indicate that the pressure between the landing platform and back shell is close to the stagnation pressure at the incipient separation moment because of the landing platform embedded in the back shell. As the separation distance increasing,the pressure between the landing platform and back shell transfers from the near stagnation pressure to near base flow pressure. The back shell will be in the base flow of the landing platform while the separation distance is 0. 1 times more than the heat shield diameters. When the separation distance is 0 ~ 0. 06 times the heat shield diameters,the axial force coefficient of the back shell is bigger than the landing platform so as to disjoin easily. When the separation distance is 0. 06 ~ 6 times of the heat shield diameters,the axial force coefficient of the back shell is smaller than the landing platform so that there will be a recontact risk after the back shell separation. Especially while the separation distance is 1 time of the heat shield diameters,the suction between the back shell and landing platform will reach the peak value because of the backwash effect so that the risk factor will become the highest. When the separation distance is more than 6 times of the heat shield diameters,the axial force coefficient of the back shell is larger than the landing platform again so as to ensure the successful back shell separation.更多还原