圆锥形喷管的脉冲激光推进能量相似律数值模拟

Numerical simulation of energy law of similitude of conical nozzles for laser propulsion in repetitively-pulsed mode

为了验证理论分析得到的圆锥形喷管在单脉冲条件下的激光推进能量相似律,用2维轴对称辐射流体动力学方法,计算得到了不同构形的推进性能参数,分析了锥角、长度、无量纲因子、入射激光能量对冲量、冲量耦合系数的影响。计算揭示的激光推进能量相似律合理,在理论模型可以描述的范围内,其定性规律与理论分析、实验结果之间相互印证。结果表明:当锥角固定时,冲量和冲量耦合系数随无量纲因子先增大后减小,极大值对应的无量纲因子仅与气体比热比相关;当无量纲因子固定时,冲量随入射激光能量增加而增大,冲量耦合系数受激光能量的影响很小,冲量和冲量耦合系数均随锥角增大而单调减小。

In order to validate the energy law of similitude for conical nozzles under the irradiation of single laser pulse predicted by analysis,a numerical simulation belonged to the radiation gas-dynamics scope is used to calculate propulsion performance parameters for a set of different nozzle sizes,and the effect of cone angle,generatrix length,the dimensionless factor introduced in theory,and incident laser energy on impulse and impulse coupling coefficient is gained,respectively.The energy law of similitude got by simulation is right,since qualitative conclusions are consistent with those derived by theoretical analysis and laboratory study in the scope that can be described by the analysis models.The results show that,impulse and impulse coupling coefficient firstly increase and then decrease with the augment of the dimensionless factor when cone angle is fixed;impulse increases with the enhancement of incident laser energy,and impulse coupling coefficient is independent of it,while they both decrease with the augment of cone angle when the dimensionless factor is fixed.