Abstract
Heat transfer and turbulent water flow over a double forward-facing step were investigated numerically. The finite volume method was used to solve the corresponding continuity, momentum, and energy equations using theK-εmodel. Three cases, corresponding to three different step heights, were investigated for Reynolds numbers ranging from 30,000 to 100,000 and temperatures ranging from 313 to 343 K. The bottom of the wall was heated, whereas the top was insulated. The results show that the Nusselt number increased with the Reynolds number and step height. The maximum Nusselt number was observed for case 3, with a Reynolds number of 100,000 and temperature of 343 K, occurring at the second step. The behavior of the Nusselt number was similar for all cases at a given Reynolds number and temperature. A recirculation zone was observed before and after the first and second steps in the contour maps of the velocity field. In addition, the results indicate that the coefficient pressure increased with increasing Reynolds number and step height. ANSYS FLUENT 14 (CFD) software was employed to run the simulations.
Highlights
IntroductionThe goal of this study is to investigate two-dimensional double forward-facing step flows, and the results of numerical computations for different step heights, temperatures, and Reynolds numbers are presented
The results show that the Nusselt number increased with the Reynolds number and step height
The goal of this study is to investigate two-dimensional double forward-facing step flows, and the results of numerical computations for different step heights, temperatures, and Reynolds numbers are presented
Summary
The goal of this study is to investigate two-dimensional double forward-facing step flows, and the results of numerical computations for different step heights, temperatures, and Reynolds numbers are presented . Numerous studies have been performed on single forward- and backwardfacing steps; the literature on double forwardand backward-facing steps is very limited, and the physical basis of flow separation and vortex creation remains unclear. The first attempts to study heat transfer and fluid flow over forward- or backward-facing steps were made in the 1950’s. Seban et al [1] and Seban [2] pioneered the study of fluid flow over backward- and forward-facing steps from a heat transfer perspective. The effect of stream turbulence on the heat transfer rate in the reattachment region on the bottom surface of a backward-facing step was demonstrated by Mabuchi et al [3]. Improvements in device capabilities have allowed researchers to measure reattachment points and heat transfer characteristics; Mori et al [4] used a thermal tuft probe, Kawamura et al [5, 6] obtained the temporal and spatial parameters of heat transfer in the reattachment region using a new heat flux probe, and Oyakawa et al [7, 8]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
