Direct numerical simulation of turbulent flow and heat transfer in a particle-laden turbulent channel flow

Direct numerical simulation (DNS) is conducted to investigate the impact of solid particles on heat transfer in a plane channel flow. For comparison, two corresponding DNSs of unladen channel flow are also performed. The numerical simulation of the particle-laden case employs a two-way coupled Eulerian–Lagrangian computational model, which allows for the consideration of momentum transfer between the two phases: discrete particles and the continuous fluid phase. The presence of particles results in an increase in the mean temperature, the root mean square (rms) of temperature fluctuations, and the streamwise turbulent heat flux within the core region. Furthermore, particles exert a more significant influence on these characteristics at higher solid volume fractions. Additionally, the correlation between velocity and temperature is affected by the presence of particles. When comparing heat transfer in particle-laden channel flow to that in the corresponding unladen channel flow, it is observed that the difference in heat flux arises from changes in the rms of the wall-normal velocity and temperature fluctuations. The impact of particles on turbulent heat flux transport is significant in the vicinity of the wall, while their influence within the core region is relatively small.