铝制旋转抛物面型激光推力器温度效应的实验研究

研究了激光推进中铝制旋转抛物面型推力器的温度变化情况。采用脉冲TEA-CO2激光器作为推进光源，用响应较快的K型热电偶丝作为温度传感器，分别在大气呼吸和烧蚀两种工作模式下，研究了抛物面上不同点的温度分布情况，以及脉冲个数和环境气压对抛物面温度的影响。文中对冲量耦合系数和气压的关系也作了研究，并将其与温度联系起来。结果发现在旋转抛物面的顶点处温度为最高，随离顶点距离的增大而减小。在大气呼吸和烧蚀两种模式下，抛物面温度随着激光脉冲个数增加，但增加的斜率逐渐减小，有饱和的趋势。在激光脉冲个数确定的条件下，大气呼吸模式的温度随气压的减小先增大后减小，出现一个峰值；烧蚀模式则随气压的减小而增大。在大气呼吸模式下，冲量耦合系数随着气压的减小先略为增大而后迅速减小，在约0．5atm处出现了一个弱峰；在烧蚀模式下，冲量耦合系数随气压减小迅速升高，在气压低于0．5atm后，几乎为定值。

Experimental Study on Temperature Effect of Aluminium Rotating Parabolic Laser Thruster

Temperature effect on aluminium rotating parabolic thruster in laser propulsion was studied experimentally. Using high power pulse TEA-CO2 laser and K type thermocouple, the temperature distribution on a parabolic reflector and the temperature response under different pulse number and atmospheric pressure were investigated in air-breathing and ablation mode, respectively. The relation between Impulse coupling coefficient Cm value and pressure was also studied connected with tempreature. It is found that the temperaure distribution has a maximum at the parabola vertex, and decreases along with the distance from the vertex. The temperature increases with the pulse number in both air-breathing and ablation mode. But the slope of rising temperature is decreasing and presents a tendency of reaching a limit. For a certain pulse number, in air-breathing mode, the temperature increases at first then decreases along with the atmospheric pressure decreasing, forming a peak; but in ablation mode, the temperature increases continually with the pressure decreasing. In air-breathing mode, along with the pressure decreasing, the Cm value increases a little at first then decreases sharply after 0.5 atm forming a small peak; while in ablation mode, Cm value increases with pressure and nearly maintains a constant after 0.5 atm.