Heat Transfer in Gas-Liquid Taylor Flow in Mini-Scale Coiled Tubes

Abstract

This paper focuses on heat transfer in gas-liquid Taylor flows in mini-scale coiled tubes. An experimental study is conducted to investigate the effects of liquid slug ratio, radius of curvature, and Prandtl number. Previously, the conducted studies on Taylor flows in straight tubes revealed that heat transfer rates are related to the flow segmentation ratio. Single-phase flows show a higher heat transfer rate in the coiled tubes. In the present study, an experimental setup is assembled using open loop of mini-scale coiled tubes subjected to a constant wall temperature. The Taylor flow data are carefully collected using 0.65, 1 and 3 cSt silicone oils and segmented by gas phase at 0.5 liquid fraction. Three coils of radii, 10, 20, and 40 mm are formed to demonstrate the effect of the secondary flows on the heat transfer rates. The results are presented in the dimensionless forms of the Nusselt number. A new model is proposed to predict Nusselt number of the gas-liquid Taylor flow in coiled tubes. This achievement presents a significant insight on the heat transfer in mini/micro scale channels.