超低轨航天器气动特性快速预测的试验粒子Monte Carlo方法

Test particle Monte Carlo method for rapid prediction of aerodynamic properties of spacecraft in lower LEO

超低轨(LEO)卫星气动特性的快速准确计算是对其进行轨道预测和控制的关键输入条件。基于真空技术领域中计算管道分子流率的试验粒子Monte Carlo(TPMC)方法,结合自由分子流理论,发展了一套快速准确预测低轨卫星气动特性的TPMC方法,给出了其模拟步骤及主要关键技术点,并采用该方法模拟了带电池翼超低轨卫星的气动特性和航天器典型构件之间的多次反射效应。结果表明:TPMC方法在计算超低轨航天器气动力、力矩时具有较高的可靠性和对工程复杂外形的适用性;该方法能够准确模拟自由分子流理论无法求解的多次反射问题,给出正确的气动力系数;该方法的计算速度比直接模拟Monte Carlo(DSMC)快3~4个量级,存储量要求也比后者低1~2个量级,是超低轨航天器气动特性快速准确预测的一个理想方法。

Fast and accurate prediction of aerodynamic properties of satellites in lower low Earth orbit （LEO） is a fundamen- tal prerequisite for determination and control of the orbit. Based on the test particle Monte Carlo （TPMC） method for the cal- culation of molecular flux rate through a pipe in vacuum technology, the TPMC method for fast and accurate prediction of aer- odynamic properties of spacecraft in lower LEO is developed, combined with the free-molecular theory. The main simulation processes and important procedures are presented. The method is validated by comparing the aerodynamic properties of a satellite with two solar panels with the results from the direct simulation Monte Carlo （DSMC） technique and the panel inte- gral method based on free-molecular flow theory. It is indicated that the TPMC method is applicable to complex configura- tions in engineering. Results also shows that the TPMC method is capable of dealing with multiple reflections that the panel integral method cannot consider, resulting in an accurate aerodynamic coefficient. In addition, the CPU time and physical memory used by the TPMC method is less than that by the DSMC technique by an order of 3 to 4 and 1 to 2, respectively, without compromising the solution accuracy. The TPMC is found to be an ideal method for fast and accurate prediction of aer- odynamic properties of satellites in lower LEO.