电弧加热发动机尾流的光谱诊断

电弧加热发动机是一种为航天器提供机动和控制推力的装置。由于比冲远高于传统的使用化学推进剂的发动机，近年来，电弧加热发动机引起了愈来愈多的关注。为了了解电弧加热发动机的工作过程机理，讨论了电弧加热发动机尾流的诊断方法并设计了一套光谱诊断系统。在此系统上，以氩气为工作气体，设定气流量和电流，在模拟空间环境下对电弧加热发动机尾流的光谱信号进行了采集。实验结果表明系统具有较高的信噪比，可以忽略噪音对光谱信号强度的影响，采集到的数据能够真实地反映物理过程。通过对采集到的谱线强度信号进行分析和处理，得到了尾流中氩的谱线发射系数的径向分布，并进一步得到了尾流平均激发温度的径向分布。实验结果表明电弧加热发动机的尾流处在热力学非平衡态下，因而用谱线强度法测温时选用不同的谱线，得到的温度值是不同的。

Spectrum Diagnostic of Arcjet

Arcjet is a kind of propulsion device for mechanical operation and control of spacecraft. As its specific impulse is far greater than classical device using chemical propellant, arcjet is playing an increasing role in spacecraft propulsion. To improve our understanding of its working mechanics, the diagnostic method of arcjet is discussed and a set of spectrum diagnostic system is established in this paper. With this system, spectrum diagnostic was executed for Ar propellant at a setting value of flow rate and input current in a vacuum chamber. The result shows that the system has a high signal to noise ratio and the data colleted can reflect the physical process objectively. Through transaction and analysis of these data, radial distribution of emission coefficient was obtained for different spectral lines, and radial distribution of temperature was also obtained through farther analysis of the emission coefficient. The result shows that under the experiment conditions of this paper, arcjet is in thermodynamic non equilibrium state, therefore the temperatures obtained by different spectral lines are different.