Liquid-liquid Taylor flow heat transfer: Correlations for predicting Nusselt number and pressure drop based on four independent variables

Abstract

The numerical simulation of heat transfer in Taylor flows involving water-light mineral oil, water-hexadecane, and water-dodecane configurations was conducted, considering water as the primary phase in three scenarios and oils as the primary phases in three others. Additionally, an investigation into heat transfer in Water-AR20 silicon oil with water as the primary phase was undertaken. In each Taylor flow scenario, two correlations were presented for predicting the thermally developed Nusselt number and pressure drop per unit length, obviating the necessity for experimental observation or numerical simulation. In cases where water served as the secondary phase, fully developed Nusselt number of the two-phase flow increased as the dimensionless effective diameter of the water droplets increased. Anomalously, when water was the primary phase, an optimal dimensionless effective diameter, equivalent to 1 for the secondary phase droplets, resulted in maximum Nusselt. The findings indicated that utilizing water as the primary phase leads to superior heat transfer capacity compared to employing oils as the primary phase. Furthermore, it was deduced that, under the condition where the effective diameter of the secondary oil droplets is set at 1 and three other variables are the same, alterations in oil type yields negligible variations in the Nusselt number. The findings of this paper can be a guide in applying liquid–liquid Taylor flow as a coolant in microchannel heatsinks.