HEAT LOSS REDUCTION AND PERFORMANCE IMPROVEMENT OF A DC ARCJET

为了研究直流电弧加热发动机的热损失机理，提高电弧加热发动机的推力性能，采用分段阳极喷嘴，通过测量冷却沃茨表面的温升，研究了阳极表面的热损失分布。为了测量弧柱的电子温度分布，设计并制作了一个高分辨率的光学测量系统，与一个新的CCD相机耦合的单色器，在过去的实验中已经使用。结果表明，通过选择合适的工作参数和几何设计参数，如推进剂流量、放电电压、放电电流、放电电压、放电电压、放电电流等，可以通过降低阳极喷管喉部的电子温度和电弧柱的热导率来降低阳极喷管的热损失通量。喷嘴形状。

The purpose of this research work is to investigate heat loss mechanisms in a DC arcjet by measuring heat loss flux from arc column to electrodes and electron temperature of the plasma with an optical measurement system and to improve thruster performance of the arcjet.Using an segmented anode nozzle of the arcjet, heat loss distributions at the anode surface were investigated by measuring the temperature rise of cooling waters. To measure electron temperature distributions of the arc column, a high-resolution optical measurement system was designed and fabricated with a new CCD camera coupled with a monochrometer which had been used in the past experiment. With these experimental devices, we could obtain the above distributions and the relationship between the heat loss flux and electron temperature.As a result, it was found that the heat loss flux to the anode nozzle can be reduced by lowering electron temperature and thermal conductivity of the arc column at the nozzle throat with a proper choice of operating and geometric design parameters such as propellant flow rate, discharge voltage, and nozzle shape.