Heat Transfer and Turbulent Fluid Flow over Vertical Double Forward-Facing Step

Abstract

Abstract — Numerical study of heat transfer and fluid flow over vertical double forward facing step were presented. The k-w model with finite volume method was employed to solve continuity, momentum, and energy equations. Different step heights were adopted for range of Reynolds number varied from 10000 to 40000, and range of temperature varied from 310K to 340 K. The straight side of duct is insulated while the side of double forward facing step is heated. The result shows augmentation of heat transfer due to the recirculation region created after and before steps. Effect of step length and Reynolds number observed on increase of local Nusselt number particularly at recirculation regions. Contour of streamline velocity is plotted to show recirculation regions after and before steps. Numerical simulation in this paper done by used ANSYS FLUENT 14. Keywords — Turbulent flow, Double forward, Heat transfer, Separation flow.I. I NTRODUCTION HE crises of energy in global has been encourage researchers to look for new techniques which improve of thermal performance. One of common method to increase efficiency of energy system equipment is by change the design geometry of channel. The fluid flow over forward or backward-facing step found in many practical applications such as heat exchangers, chemical process, turbine blades, and power plants. There are many experimental and numerical study of effect separation flow at forward or backward-facing step on increase of enhancement heat transfer rate. Heat transfer to fluid flow over single and double forward-facing step experimentally studied by Shakouchi and Kajino [1] with using laser Doppler anemometer where the results appeared that the reattachment region by a new heat flux probe, and Oyakawa et al. [2], [3] used jet discharge. Saldana and Anand [4] performed numerical study of laminar fluid flow over a horizontal forward-facing step in three dimensions. They showed that the increase of Reynolds number leads to increase of reattachment length and average Nusselt number.