Spatial Distribution of $\hbox{C}_{2}$ Spectra From Induction Thermal Plasmas With Polymer Powder Injection

Abstract

The influence of polymer ablation on thermal plasmas was fundamentally investigated by using the induction thermal plasma technique. Polymer powders were directly subjected to Ar-induction thermal plasmas. A high-speed video camera, with a bandpass filter, was used to measure the spatial distribution of the spectral radiation intensity of C 2 molecules included in the polymer-ablated vapor. Numerical prediction was also undertaken to obtain the C 2 molecular fraction distribution. Results directly show the mixing aspects of polymer-ablated vapor with thermal plasmas.Index Terms-Inductively coupled plasma, polymer ablation, thermal plasma. U NDERSTANDING the interaction between solid materials and thermal plasmas is increasingly important for various applications, such as thermal plasma material processing. The interaction between polymer materials and thermal plasmas is also crucial for the effective design of recently downsized circuit breakers. In high-voltage circuit breakers, for example, an arc plasma formed between the electrodes can contact a polymer nozzle during a current interruption process. Then, the heat and high-intensity radiation from the arc plasma cause the ablation of the polymer material. In this case, the polymer ablation invariably contaminates the arc plasma, changing the insulation and arc-quenching properties of the gas inside the circuit breaker. It also produces a jet gas flow and a marked pressure rise in the circuit breakers, involving the exchanges of mass, momentum, and energy between the polymer and the thermal plasmas. The aforementioned effects markedly affect the interruption capability of the circuit breaker. However, the polymer ablation phenomena and the resultant phenomena are very complex in the circuit breaker, which make it difficult to elucidate the polymer ablation effects.We have proposed the use of an inductively coupled thermal plasma (ICTP) technique for the fundamental study of the interactions between cold gas and thermal plasmas [1] and between solid powder and thermal plasmas [2], [3]. The ICTP requires no electrodes to be sustained. This feature enables us