计算模拟月壤颗粒吸收及散射特性的一种球叠加模型

A sphere super-position model to calculate the absorptive and scattering radiative characteristics of lunar dust simulant

针对模拟月壤复杂的外形特征以及多相非均质的微观结构,提出了一种计算模拟月壤颗粒吸收及散射特性的球叠加模型。根据模拟月壤颗粒的形状指数和分形特征识别结果,归纳了4种主要的模拟月壤颗粒类型,并采用蒙特卡罗光线跟踪法研究了这4种颗粒在单色平行光照射下的吸收及散射特性。与已有的非球形颗粒辐射特性的算法比较显示,该模型具有良好的计算准确性。在数值计算的基础上,分析了颗粒尺度参数及光学常数对其自身辐射特性的影响,并通过改变平行光照下的光线入射角度,分析了非球形颗粒的朝向对其自身辐射特性的影响。由计算结果推断,该模型不仅可以应用于计算模拟月壤颗粒的辐射特性,还可以满足其他适用于几何光学近似的非球形粒子。

Based on the complex external physical characteristics and the inhomogeneous microstructure of the lunar dust simulant, a sphere super-position model is proposed to calculate its absorptive and scattering radiative characteristics. Four major types of simulant lunar dust particles are identified based on its shape factor and fractal feature, and then the radiative properties of these particles under a monochromatic collimated radiation are studied by using the Monte Carlo ray tracing method. A comparison with known algorithms of nonspherical particles shows a good accuracy of our model. Based on the data from the numerical calculation, the influences of the particle size parameter and the optical constants on the radiative characteristics are analyzed and the phase functions of different particles are calculated. The effect of the particle orientation on its radiative features is also studied by changing the illuminating angle of the incident radiation. Results show that this model can be used not only to study the simulant lunar dust, but also to calculate other large nonspherical particles with even more complex microstructures.