On the Heat Transfer in Particle-laden Turbulent Flows: the Effect of Collision in an Anisothermal Regime

In this study, we investigate a two-way thermally coupled collisional turbulent particle-laden flow using Eulerian-Lagrangian point-particle direct numerical simulations. Our aim is to examine the impact of inter-particle collisions on heat transfer in a time-evolving thermal mixing layer that develops between two homothermal regions, which are carried by a homogeneous and isotropic turbulent flow. Our results cover Stokes numbers between 0.2 and 3, with a ratio of thermal Stokes number to Stokes number equal to 4.43, at a Taylor microscale Reynolds number up to 124. We found that particle collisions tend to reduce the particle temperature-velocity correlation, which results in a small decrease in the average heat transfer compared to a collisionless regime at large Stokes numbers.