前缘切口参数对大型冲压式翼伞的性能影响分析

摘要

影响冲压式翼伞气动性能的主要参数除翼型结构参数外,还有翼伞前缘切口角度和前缘切口长度.为了更准确地找到冲压式翼伞前缘切口参数适用的工程应用范围,文章以某大型冲压式翼伞的基础翼型剖面为研究基础,通过改变前缘切口角度和前缘切口长度这两项重要参数,得到四种具有代表性的前缘切口参数的翼型剖面,并采用数值计算方法对其气动性能进行分析.研究表明:负攻角时,上翼面的压力梯度随前缘切口角度的增大而增大,而下翼面的压力梯度随前缘切口角度的增大而减小;正攻角时,前缘切口角度对上、下翼面的压力梯度没有太大影响;同时,随着前缘切口角度的增加,翼型最大升阻比也增大,但是会有一个临界值,而前缘切口参数对翼型俯仰力矩系数的影响并不大.文章的研究结果对翼伞的设计优化有一定的参考意义.%In addition to the structure parameters of the airfoil profile, the angle and the length of leading edge cut are the main parameters that affect the aerodynamic performance of the ram-air parachute. In this paper, based on the fundamental airfoil profile of the large ram-air parachute, two important parameters, the angle and the length of leading edge cut, are changed and four kinds of airfoil profile with representative parameters of leading edge cut can be obtained in order to find the range of engineering applications on leading edge cut parameters more accurately. The numerical calculation method is adopted to study the aerodynamic performance of four airfoils and the results show that the pressure gradient of upper surface grows and the pressure gradient of lower surface decreases with the increase of the angle of the leading edge cut at negative angles of attack, while the angle of leading edge cut does not have significant effect on the pressure gradient of the upper and lower surface at positive angles of attack. With the increase of the angle of leading edge cut, the maximum lift-drag ratio of the airfoils also increases, but there will be a threshold. The influence of the leading edge cut parameters on the pitch moment coefficient is not significant. The results of this paper provide some reference value for design and optimization of ram-air parachute.