Effect of corner shape on pressure loss and heat transfer of turbulent channel flow with T-junction

Abstract

An experimental study is performed for dividing turbulent channel flow in 90 degree T-junction with sharp, inclined and rounded corners. Experiment is conducted for flow rate ratios of 0.2, 0.4, 0.6 and 0.8 (ratio between the flow rates in the branch and main channels) keeping the Reynolds number of the main flow at 4.0×104. The width of the main channel H1 is maintained at 30mm, and the width of the branch channel H2 is changed into 15mm, 30mm and 45mm. The loss coefficient and wall static pressure coefficient are measured to quantify the energy loss. The local heat transfer coefficient is measured at the branch channel. To investigate the relationship between fluid flow and heat transfer, the velocity profiles are measured by a PIV system. Rounding the corner reduces the pressure loss in the branching flow. As the ratio of the width of branch channel to the width of main channel becomes small, the reduction rate of pressure loss in the branch flow increases. Whereas the pressure loss in the main channel basically remains unaffected. Except the low flow rate ratio, the heat transfer coefficient in the branch channel decreases at the rounded corner as compared with the sharp corner. Decrease of the heat transfer coefficient is related to the reduction of the recirculation region which occurs at the upstream wall of the branch channel.