Numerical Investigation on Effect of Appendage on Heat Transfer in a Backward-Facing Step (BFS)

In the present study, convective heat transfer, in a laminar two-dimensional flow of a backward-facing geometry is analyzed. The effect of introduction of an appendage at the edge of the step, to provide an obstruction in the flow and thus to enhance the heat transfer, has been numerically studied. The governing equations are solved in the finite volume method. The flow is considered to be laminar. Air with a Prandtl number of 0.7 is considered as the fluid. The effect of variation of Reynolds number (1 ≤ Re ≤ 1000), on various appendages is analyzed. The heat transfer enhancement is studied by primary recirculation length, average Nusselt number, pressure coefficient and performance evaluation criteria (PEC). The effect of orientation of the appendages has also been studied. The best improvement in heat transfer rate over the backward-facing step is generated by an appendage of length and has a value of YA/S = 0.84. However, PEC and pressure coefficient analysis indicate an appendage of YA/S = 0.33 and 0° is more suitable for increasing the heat transfer for a nominal pressure drop.