【作者】 童慧峰；

【导师】 唐志平；

【作者基本信息】 中国科学技术大学 ， 工程力学， 2006， 博士

【摘要】 激光推进是利用高能激光与工质相互作用产生的反作用力推动飞行器前进的一种新概念推进技术。与传统的化学推进相比，激光推进在概念上的创新主要可归结为两个分离：1、工质和能量的分离，2、飞行器和能源系统的分离。从是否消耗自身携带工质看，激光推进的驱动模式可分为两类：大气模式和火箭烧蚀模式。本文就火箭烧蚀模式激光推进进行探讨，采用模型分析、数值模拟以及实验研究等几个方面，从物理、力学的角度深入研究烧蚀模式激光推进的物理机理和力学规律，得到了一些有益的结果。 以激光与固体靶相互作用的动态物理过程为线索，分析了烧蚀模式激光推进的基本原理，并将其划分为三个过程阶段：①靶材料表面的受热气化过程；②靶面蒸气与入射激光的相互作用并使得蒸气继续电离、升温的过程；③靶面蒸气等离子体的膨胀运动过程。激光烧蚀压力和冲量耦合系数是衡量激光推进效应的重要参数，详细分析了基于LSD的激光推进效应力学模型。 介绍了一维辐射流体动力学代码MEDUSA，给出了MEDUSA程序的主要计算流程图。采用MEDUSA程序对单脉冲激光与固体靶相互作用的动态物理过程进行了数值模拟计算。得到了一维情形下等离子体各参数(粒子速度、密度、温度)的随时间以及空间的变化，并给出了动态烧蚀面(激光束与固体靶的作用面)压力随时间的动态变化规律。采用烧蚀压力随时间积分的方法计算固体靶所获得的作用冲量，分别计算了铝靶材料和C-H靶材料在不同激光参数条件下的推进性能。计算得到的冲量耦合系数与实验结果以及经验模型进行了比较，结果表明，数值计算结果与实验结果符合较好。 采用一种平均电离度的简易快速计算方法并由此给出等离子体状态方程，以及具有五阶精度的加权本质无振荡差分格式-WENO建立了烧蚀模式激光推进数值模拟程序，考虑了入射激光与固体靶的相互作用，着重于激光与固体靶面蒸气等离子体的相互作用与能量耦合，用于模拟激光作用于固体靶产生等离子体喷射的全过程，包括固体靶表面吸收激光能量气化、电离产生等离子体，入射激光与靶面等离子体的能量耦合及能量屏蔽，靶面的后续动态烧蚀。进行了以下几个方更多还原

【Abstract】 Laser propulsion, which works on the counterforce generated during the interaction between high-power laser and propellant, is a new concept technique for propulsion. Compared with traditional chemical propulsion, the main innovation in concept of laser propulsion reduces to two separations: separation of energy and material, and separation of aero-craft and energy source system. In general, there are two main modes, the rocket ablation mode and the air-breathing mode, which divided by whether consume the taking material or not. In the present thesis, it focuses on the ablation mode laser propulsion, physical and mechanical mechanism of ablation mode laser propulsion have been studied by model analysis、 numerical simulation and experiment study, some main conclusions are reached and will be listed as follows.The principle of ablation laser propulsion (ALP) was analyzed on the dynamic physical processes of laser target interaction, and can be divided into three stages. The process of vapour of solid target surface material; the process of temperature rise and ionization of target vapor under interaction with laser pulse; the process of free expand movement of plasma. The ablation pressure and mechanical coupling coefficient are the important parameters of laser propulsion. The mechanics propulsion efficiency model based on LSD (laser supported detonation) was detailed analyzed.1 -D radiation-hydrodynamic code MEDUSA was introduced, and presented the main floe chat of MEDUSA. The dynamic physical process of single-pulse laser interaction with solid target was simulated by use of MEDUSA code; the parameters of ablated plasma (particle velocity, density, temperature) variety of time and space were obtained, and presented the pressure of ablated surface (the surface of laser target interaction) variety of time during the laser pulse. The impulse solid target obtained can calculate by integral the pressure of time, thus can calculate the mechanical coupling coefficient c_m. The propulsion efficiency of Al target and C-H target of different laser parameters were simulated, and compared with experiments and empirical model results, which showed that the simulated results were believable.A general Godunov finite difference schemes-WENO (Weighted Essentially Non-Oscillatory) schemes which have fifth-order accuracy is used to make a numerical calculation for 2-dimensional axis symmetrical laser-supported plasma flow field under laser ablated solid target and laser ablated propulsion efficiency更多还原