CFD study of the heat transfer between a dilute gas particle suspension flow and an obstruction

The heat transfer process between a dilute gas-particle suspension flow and an obstruction has been numerically investigated employing our novel Euler ian formulation for dilute gas particle suspension flows [1], which allows interaction of the key mechanisms to be quantified for the first time, ils the particle reflection occurs around the obstruction, the heat transfer pr ocess has been modeled taking into account the incident and reflected parti cles explicitly. In the energy equations these particle families are treate d separately. Only the effect on the gas convective heat transfer is expect ed to be of primary significance and investigated The numerical computation is performed using the commercial computational fluid dynamics code, FLUEN T, with our User Defined Subroutines. We study the heat transfer process be tween a dilute gas particle flow and an obstruction with simple geometries such as a 45 degrees ramp and a cylindrical tube. The theoretical results f or the latter case are compared with the available experimental data. Our n umerical simulation shows that both the particle size and the particle conc entration (in the thermal boundary layer) affect the heat transfer process. Since both the particle incidence and reflection depend on the particle si ze and strongly influence the particle concentration distribution, they hav e to be physically correctly treated in the modeling of the heat transfer, as is demonstrated in our novel formulation. There is an optimum particle s ize for a maximum enhancement of the heat transfer. The particle concentrat ion increases the efficiency of the heat transfer process expressed in term s of the local Nusselt numbers.