A new set of aerodynamic correlations are proposed for an ellipsoidal particle in the free molecular regime by carrying out flow simulations using the Direct Simulation Monte Carlo (DSMC) method. The in-house DSMC solver is modified to be consistent with free molecular flow assumptions as well as to reduce computational cost. The solver is validated against an open-source DSMC solver, viz., SPARTA, the free molecular theory and experimental data for flow over a sphere and right circular cylinder in the free molecular regime. The flow is simulated over ellipsoidal particles at different aspect ratios, angles of attack and speed ratios to estimate the aerodynamic properties. Regression analysis is performed to give correlations for the variation of aerodynamic properties such as drag, lift and torque coefficients. The correlations are rigorously tested against the DSMC results, obtained from our in-house solver as well as those obtained from SPARTA, over a wide range of parameters.

通过使用直接模拟蒙特卡洛（DSMC）方法进行流动模拟，为自由分子状态下的椭圆形粒子提出了一组新的空气动力学相关性。内部DSMC求解器经过修改，以符合自由分子流假设并降低了计算成本。该求解器已通过开源DSMC求解器（即SPARTA），自由分子理论和在自由分子状态下流经球体和直圆柱体的实验数据进行了验证。在椭圆形颗粒上以不同的长宽比，迎角和速度比模拟气流，以估算空气动力学特性。进行回归分析以提供空气动力学特性（例如阻力，升力和扭矩系数）变化的相关性。