Numerical analysis has been performed on the motion of a spherical particle injected into high temperature thermal plasma flows in order to disclose the mechanisms of heat transfer enhancement and to establish reliable correlations for heat transfer between the plasma gas and the particle. In terms of fluid dynamics occurring, the Navier-Stokes equations were solved for Ar-H2 mixture plasma gas in a two-dimensional system by finite element method (FEM). Computational simulation was undertaken to model the correlations for fine spherical particles in Ar 25%-H2 75% as plasma gas from 1100 to 9100 K at atmospheric pressure. Our results reveal the general consensus of Nusselt number, followed by increasing deviations as the temperature increases. Additionally, a comparison between our data and the predictions of other published correlations are given.