Simulation and analysis of heat transfer and particle deposition characteristics in dimple channel flow fields: based on two different methods

: Particle deposition within heat-transfer channels significantly alters the local flow and thermal characteristics, thereby affecting overall heat-exchange performance. In this study, the heat-transfer behavior and particle deposition on the surface of a concave dimple channel are investigated using numerical simulations. For the fluid phase, both the Reynolds-Averaged Navier–Stokes (RANS) method and the Large-Eddy Simulation (LES) method are adopted. For the particle phase, the discrete random walk (DRW) model and a user-defined particle–wall rebound model are employed. The results show that the LES method provides higher accuracy than the RANS method when the particle size is medium and large or when the number of dimple rows exceeds five. Compared with RANS, LES predicts a stronger tendency toward wall-convergent deposition for large particles. Introducing concave dimples enhances heat transfer, leading to an approximately 50% increase in the Nusselt number ( Nu ). In the RANS results, Nu remains nearly uniform among different dimples, whereas LES predicts significantly higher Nu in the downstream dimples due to intensified vortex interactions. These findings highlight the applicability and limitations of RANS and LES in simulating particle-laden dimpled channels and provide guidance for the design and optimization of high-efficiency heat-exchange structures.