Heat transfer enhancement in a ribbed T-shaped microchannel by oil-water slug flow

Abstract

Background

Droplet-based microfluidics is an emerging technology for thermal management of high heat dissipating systems and electronics cooling.

Method

The current work investigates the potential of slug flow for thermal management of mini-sized heat dissipating devices and microchannels. Hydrothermal characteristics of oil-water slug flow including droplet size, liquid film thickness, pressure drop, and heat transfer have been studied in a T-shaped microchannel. Three dimensional numerical simulations have been carried out for two types of ribbed channels with short and long obstacles at different flow rates.

Findings

Results indicate that droplet size and liquid film thickness directly and reversely affect the heat transfer rate, respectively. The former intensifies the flow recirculation, and the thermal boundary layer disturbance while the latter changes the dominant heat transfer mechanism to conduction. On the whole, a maximum of 55 % heat transfer enhancement has been achieved relative to the single-phase water flow. It is also observed that by using obstacles on the channel surface, the heat transfer enhancement can be further increased with a slight pressure drop penalty.