Thermal Performance of Heated Cylinders in a V-Shaped Open Channel

Abstract

Abstract. In this study, forced convection heat transfer (HT) in a two-layer V-shaped open channel containing five heated circular cylinders was numerically investigated. The channel was divided into a lower porous layer (PL) saturated with fluid and an upper layer filled with clear fluid, separated by a permeable interface. The cylinders were maintained at a constant high temperature, while the channel walls were kept at a constant cold temperature. The governing equations were solved using the finite element method (FEM) with the Galerkin approach, implemented through comsolmultiphysics. The study analyzed the influence of porous layer thickness (0–100%), Reynolds number (10–500), and Darcy number (10−5–0.1) on flow and heat transfer behavior. Validation against existing literature showed good agreement, confirming the model's accuracy. Results demonstrated that introducing porous media significantly reduces vortex formation and recirculation around the cylinders by damping reverse flow due to pressure drop. Increasing Reynolds and Darcy numbers intensified the fluid motion within the porous medium (PM), while thicker porous layers led to reduced flow strength. Heat transfer by conduction was dominant within the porous region. The highest average Nusselt number occurred for porous layer thicknesses between 20% and 30%, with local Nusselt number increasing consistently with higher Re and Da values. This result will be very important for simulating and designing a channel partially filled with a porous medium, making it more efficient and less costly. These additions of porous material appear to open the door to designing a new generation of channels containing an array of hot cylinders, such as heat exchangers in various application systems.