吸气式激光推力器速度与高度耦合特性的数值研究

Numerical simulation of velocity and altitude characteristics for air-breathing laser propulsion

使用基于有限体积法和分区结构化网格划分的高分辨率数值方法，计算得到了两种吸气模式激光推力器模型在加速度为10m／s^2的发射过程中，其冲量耦合系数随海拔高度的变化规律。不考虑来流速度和空气补充时，高度特性计算结果与实验吻合得很好。结果表明：推力器与空气具有相对速度时，冲量耦合系数整体明显减小，导致激光推进单级入轨发射由吸气模式向火箭模式的切换点由目前预测的20～30km明显下移至10～20km；经过进气道增压处理后，冲量耦合系数大幅度提高，为了增大吸气模式的工作高度范围，进气道设计是必不可少的关键技术之一。

A second order accurate scheme based on finite volume method and domain decomposition of structural grid is used to compute impulse coupling coefficients of two laser thrusters with an acceleration of 10m/s^2 at different altitudes for alr-breathing laser propulsion. The curves of impulse coupling coefficients and altitude are found to agree well with experimental results without considering the inflow and air renewing. Results show that impulse coupling coefficients are obviously lower when the laser thruster has the flight speeds relatively to air, which induces that the switch range from air-breathing to rocket mode in single-stage-to-orbit laser propulsion descends to 10 -20 km from 20 -30 km forecasted at present. Impulse coupling coefficients are improved greatly by providing the required airflow at some operational flight speeds through inlet system, and design of the inlet system is one of the absolutely necessary key techniques in order to broaden the working range of air-breathing mode.