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为了增进对激光烧蚀推进中推力产生过程的认识,建立了激光烧蚀掺杂聚合物推力产生过程的模型,发展了一套包括激光能量沉积、工质烧蚀、烧蚀羽流飞散等过程的数值仿真程序。数值计算了真空中3~40J/cm~2激光烧蚀掺杂微米铝颗粒聚甲醛工质的推力、烧蚀轮廓及质量、压强分布和比冲特性,且比冲与实验数据较吻合。计算结果表明:高激光能量密度(30.0J/cm~2)较低激光能量密度(5.0J/cm~2)的金属颗粒剥蚀情况严重;低激光能量密度(5.0J/cm~2)下推力时间变化规律较简单,总体呈现先增后减的趋势,且从整体上看只有一个压强峰值;而相对较高的激光能量密度(30.0J/cm~2)下,由于存在“烧蚀-屏蔽-烧蚀被削弱”的制约关系,推力时间变化规律复杂;流场产生的高压区较多,且呈现交替产生、并存发展到衰减消失的规律;羽流与激光的相互作用更为剧烈,峰值压强也更大。
In order to enhance the understanding of thrust generation in laser ablation propulsion, a model of laser ablation polymer-induced thrust generation was established and a set of models including laser energy deposition, working fluid ablation and ablation plume scattering were developed Numerical simulation program. The thrust force, ablation profile and mass, pressure distribution and specific impulse characteristics of 3 ~ 40J / cm ~ 2 laser ablation micronized aluminum particles were numerically calculated, and the specific impulse was in good agreement with the experimental data. The calculation results show that the metal particles with high laser fluence (3.0J / cm ~ 2) have a serious erosion of metal particles, while the low laser fluence (5.0J / cm ~ 2) The time variation law is simpler and shows a trend of first increase and then decrease, and there is only one pressure peak as a whole; while the relatively high laser energy density (30.0 J / cm ~ 2) Shielding-ablation is weakened, "and the variation of thrust time is complex. There are many high-pressure zones in the flow field, alternating with each other, and the law of attenuation disappears coexists. The interaction between plume and laser is more intense , The peak pressure is greater.