Diagnostics of Three-Dimensional Temperature Distribution of Ar Arc Plasma by Spectrum Tomography Technique

In this paper, a new technology which can be used to diagnose 3-D temperature distribution of argon arc plasma is proposed. Compared with current technologies, two aspects have been improved. First, a new hybrid reconstruction technique [max-entropy, least square, and flatness reconstruction technique (MLFRT)] is presented as an algorithm system, where the numerical simulation of the MLFRT has been realized. The results show that the MLFRT has good convergence, stability, and efficiency. Second, two orthographic double-wavelength light paths have been designed in the experimental setup, which can collect intensity data in real time. Based on these data, we reconstruct the emission coefficient using the MLFRT. Then, a spectral line relative intensity method was chosen to calculate the 3-D temperature distribution, where the spectral analysis of argon arc plasma was introduced. This new technology can acquire good result by just two orthographic intensity data sets. Therefore, the experimental system is simple, and the experimental cost is low. The result is beneficial to understand the working principle of argon arc plasma, improving the level of craftsmanship. It also has good application advantages over other 3-D flow field testing, such as density field, pressure field, velocity field, etc. It shows great academic and economic value.