The effect of appendages at step on heat transfer in a backward-facing step

Abstract

The current study analyzes the effect of introduction of an appendage at the step, on forced convection, in a backward-facing step. Two-dimensional turbulent flow over a backward-facing step has been tested numerically. The length and size of the recirculation zone have been observed to vary, by changing the appendage length and Reynolds number. An increase in the average Nusselt number has been observed for an increase in the Reynolds number. In this study, it has been visualized that with the introduction of the appendage, the Nusselt number increases. A vertical fin length of Ya/S = 0.5 has been found to provide the greatest improvement in the heat transfer rate. The average Nusselt number increases by three times for Ya/S = 0.5. However, the Performance Evaluation Criteria (PEC) indicates the appendage of length Ya/S = 0.3 provides consistent values. This arises as the pressure drop increases by 8.75 times for Ya/S = 0.5 when compared with unobstructed case.