基于有效透气量对火星降落伞气动力系数预测分析

针对火星探测任务中降落伞开伞环境为低密度大气的特点,本文由降落伞气动力系数与透气量关系,提出了通过降落伞有效透气量预测降落伞气动力系数的方法,该方法先由织物透气量试验获取伞衣透气量拟合曲线和透气量常数,再根据风洞试验得到两种有效透气量下的气动力系数,然后由有效透气量插值获取了盘缝带(DGB)伞火星大气条件下气动力系数,并且通过空投试验数据对该方法进行验证。计算结果表明,在火星条件下,降落伞气动力系数与风洞条件下变化趋势基本一致。Ma 0.4工况阻力系数的变化范围为0.583～0.622,Ma 0.8工况阻力系数的变化范围为0.438～0.494。

Prediction and Analysis of Aerodynamic Coefficient of Parachute under Mars Conditions Based on Effective Porosity

Based on the low density atmosphere for parachutes in the Mars exploration missions, this paper proposes a method to predict the aerodynamic coefficient of parachute by the effective porosity according to the relationship between the aerodynamic coefficient and the total porosity. This method firstly obtains the fitting curves and the permeability constants by the fabric permeability results and data fitting. According to the wind tunnel test, the aerodynamic coefficients of two effective porosities are acquired. Then, the aerodynamic coefficients of the disk gap band (DGB) parachute are accomplished from the effective porosity interpolation. And the airdrop test data has demonstrated the effectiveness of the approach proposed. The calculation results indicate that under the conditions of Mars, the aerodynamic coefficient of parachute is basically the same as the trend with varying attack angles under the wind tunnel conditions. The variation range of the parachute drag coefficient under  Ma  0.4 is from 0.583 to 0.622, and the variation range of the parachute drag coefficient of  Ma  0.8 is from 0.438 to 0.494.