In this work, a magnetic fluid dynamics (MHD) model is used to simulate the electromagneticfield, heat transfer and fluid flow in a DC non-transferred arc plasma torch underlaminar and turbulent conditions. The electric current density, temperature and velocity distributionsin the torch are obtained through the coupled iterative calculation about the electromagneticequations described in a magnetic vector potential format and the modified fluid dynamics equations.The fluid-solid coupled calculation method is applied to guarantee the continuity of theelectric current and heat transfer at the interface between the electrodes and fluid. The predictedlocation of the anodic arc root attachment and the arc voltage of the torch are consistent withcorresponding experimental results. Through a specific analysis of the influence of mass flow ratesand electric current on the torch outlet parameters, the total thermal efficiency, thermal loss ofeach part, and the laws of the variation of outlet parameters with the variation of mass flow ratesand electric current was obtained. It is found that operation under a laminar condition with alimited area of the anode could increase the total thermal efficiency of the torch.
