Comparison of Reynolds average Navier-Stokes turbulence models in numerical simulations of the DC arc plasma torch

Five turbulence models of Reynolds average Navier?Stokes (RANS), including the standard k-epsilon model, the RNG k-epsilon model taking into account the low Reynolds number effect, the realizable k-epsilon model, the SST k-epsilon model, and the Reynolds stress model (RSM), are employed in the numerical simulations of direct current (DC) arc plasma torches in the range of arc current from 80 A to 240 A and air gas flow rate from 10 m(3) h(?1) to 50 m(3) h(?1). The calculated voltage, electric field intensity, and the heat loss in the arc chamber are compared with the experiments. The results indicate that the arc voltage, the electric field, and the heat loss in the arc chamber calculated by using the standard k-epsilon model, the RNG k-epsilon model taking into account the low Reynolds number effect, and the realizable k-epsilon model are much larger than those in the experiments. The RSM predicts relatively close results to the experiments, but fails in the trend of heat loss varying with the gas flow rate. The calculated results of the SST k-epsilon model are in the best agreement with the experiments, which may be attributed to the reasonable predictions of the turbulence as well as its distribution.