A predictive method for radial temperature profiles of low-current arcs in axial flow derived from gas properties

Low-current arcs in axially blown gases exhibit distinct features in their arc column size and temperature distribution, notably featuring multiple inflection points in the radial temperature profile. This work introduces a simplified theoretical framework, avoiding the complexity of full computational fluid dynamics models, to explain the physical mechanisms that govern the shape of the radial temperature profile. Quantitative analysis identifies that the temperature dependence of the product of gas density and specific heat capacity is the dominant factor governing profile formation under low-current conditions. Based on this finding, a predictive method is developed that uses this key gas property to estimate temperature profiles. The predicted profiles show close agreement with published experimental data, and the estimated arc column sizes reproduce observed trends in published results regarding thermal interruption capability. The proposed method provides a practical and computationally efficient tool for evaluating and selecting gases for high-voltage gas circuit breakers according to their arc-cooling performance.