HEAT TRANSFER ENHANCEMENT BY SUSPENDED PARTICLES IN A TURBULENT SHEARLESS FLOW

Numerical simulations are used to investigate the role of particle inertia and thermal inertia on the heat transfer in a particle-laden turbulent flow. By using the point-particle model, a wide range of Stokes and thermal Stokes number have been simulated in a simple configuration where a temperature discontinuity is introduced in a statistically steady homogeneous and isotropic turbulent flow with a Taylor microscale Reynolds number between 37 and 124. This configuration produces a self-similar evolution of the carrier flow and particle temperature statistics during which the Nusselt number remains constant. Our results show that the maximum contribution by particles to the heat flux is achieved at a Stokes number which increases with the ratio between thermal Stokes and Stokes number, approaching one for very large ratios. Moreover, the maximum increases with the thermal Stokes to Stokes number ratio and, relatively to the convective heat flux, it reduces as the Reynolds number increases.