In the present article it is considered the question of thermo-aerodynamic mathematical model construction of granules obtaining process by method PREP. It is conducted cooling process modeling of the particle in gas mixture of helium and argon with the account of the thermal and hydrodynamic phenomena. Time dependences of resistance force and heat-transfer factor during the particle motion are received. We have calculated the influence of cooling gases mix (90% of helium and 10% of argon on weight) on the process of VT6 titanic alloy particle cooling, taking into account phase transition of the particle from a liquid state to the firm one. It is shown that when modeling process of receiving granules of refractory metals it is necessary to allocate a crystallization stage separately.