90°T字分岐部を有するチャネル乱流の流動と熱伝達(流体工学,流体機械)

Abstract

An experimental study is performed for dividing turbulent channel flow in 90゜ T-junction. Experiments are 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 4.0×10^4. The width of main channel H_1 is kept to 30mm, and the width of the branch channel H_2 is changed 10mm, 15mm, 30mm and 45mm. The wall static pressure and loss 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 coefficient, the velocity profiles and turbulent intensities are measured by PIV. It was found that the loss coefficient in the main channel basically remained unaffected by the branch channel width, whereas the loss coefficient in the branch channel increased with decreasing the branch channel width. The dividing flow was separated at the upstream edge of the T-junction and formed a large separation babble. The heat transfer characteristics of the upstream wall at the branch channel were similar to that of the turbulent channel flow over backward-facing step.