一种计算开伞动载的实用方法

A PRACTICAL METHOD FOR CALCULATING PARACHUTE OPENING FORCES

依据海因里奇开伞动力理论，在计算个表充满时间的连续方程中，考虑了伞顶孔，伞顶部分大透气量织物面积，以及伞衣中、下部分织物透气量对开伞动载的影响。引用了非线性的阻力特征文化曲线［２］，计算伞衣充气过程中阻力特征的变化。并考虑了伞衣充气过程初始瞬时的阻力特征，假设在伞衣初始充气时期的一段时间中，进气口直径为常值，数值上等于［４（ＣＡ）０／Ｃ（ｓｔ）π）］（１／２）。计算实例表明，计算结果与实测数据相比较，其一致性是比较满意的。

ased on the H.G. Heinrich's theory of parachute opening dynamics,this paper considers the effects of vent, crown cloth area with large porocity, and porocity at the middle and lower portions of the canopy on parachute opening force. In continuity equation for calculation Filling time of parachute canopy the variation of drag area in process of canopy inflation is calculated by using the non-linear drag area variation curves. The initial parachute drag area during the inflation of parachute canopy is also considered. The constant inlet diameter is assumed and equals to (4(CA)0/ C(st)π)(1/2) during the initial phase of parachute inflation. The computation example shows that the results of calculation are in agreement with the measured data satisfactorily.