Understanding Thermo-Fluidic Characteristics of a Triangular Solar Air Heater Having W-Shaped Rib-Turbulators: A 3D Computational Fluid Dynamics Study

A solar air heater duct with W-shaped rib-turbulators on the collector plate disrupts the flow that enhances the heat transfer from the hot surface due to turbulence in the flow. In this analysis, a three-dimensional fluid domain of the W-shaped ribbed triangular solar air heater duct is numerically simulated to analyze the impact of roughness and flow parameters on thermo-fluidic performance; also, the turbulence behavior near the rib surfaces is presented. Roughness variables like non-dimensional pitch and non-dimensional height varied from 6.23 to 17.85 and 0.04 to 0.053, respectively. In contrast, the flow parameter, like the Reynolds number, is kept in the range of $4×103$ to $18×103$⁠. A maximal performance evaluation criterion of 1.51 is attained for the W-shape ribs with a non-dimensional pitch of 7.14 and a non-dimensional height of 0.047 at a Reynolds number of $15×103$⁠. For the W-shaped rib-turbulators with a non-dimensional pitch of 7.14 and a non-dimensional height of 0.047 at a Reynolds number of $15×103$⁠, the maximum heat transfer is found to be 1.826 times that of a smooth duct. Accordingly, in the parametric range, the maximum friction penalty is 2.63 times that of a smooth duct. Some useful correlations are established considering the computational data.