Heat transfer and fluid flow characteristics over a backward-facing step (BFS) containing square-rectangular ribs integrated as forward-facing steps (FFS)

Modifying the geometrical structures is a potential strategy that targets the compactness of any new devices in order to produce greater cooling performance. The heat transfer enhancement over a BFS with unique square-rectangular ribs as FFS in a two-dimensional channel is investigated numerically in this study. Each of the structures features a pair of square-rectangular adiabatic ribs, and both its height and width are adjustable. The ribs are positioned uniformly on the bottom wall heated with uniform heat flux. The impacts of varying number as well as space in between the pair of ribs are also analyzed. Fresh external fluid is entering into the channel from the left and leaving the channel from the right. The methods of solution of the mathematical models are solved numerically following the finite element method along with the Galerkin technique. Through the rigorous computation, the results are obtained and presented systematically over wide range of parametric variations like: with height and width of square-rectangular ribs, space between each pair of ribs, number of ribs, heat flux strength, and flow Reynolds number. In order to compare the thermal performance of BFS with ribs structure, the case of no-ribs channel is also investigated. The results indicate that geometric parameters have major influences on the thermo-fluid flow as well as heat transfer characteristics. It is found that lesser number of ribs with moderate height and width with lesser spacing corresponds to the superior thermal performance compared to no-ribbed channel. Furthermore, lower number of ribs with higher height and width with higher spacing resembles to the worst thermal performance.