Heat transfer of power-law fluids under electrowetting actuation in structured microchannels

Abstract

The dynamics and heat transfer performance of droplets play an important role in electrowetting systems. Contrary to the growing trend towards non-Newtonian fluids in electrotechnical systems, most researchers have focused on Newtonian fluids. In the current study, the interface is tracked by the phase-field method and afterwards, the numerical model is confirmed by comparing the results obtained from previous experimental and theoretical works. Several parameters such as power-law index and contact angle are analyzed. Furthermore, the dynamics and heat transfer of the droplets on chemically or topographically structured substrates in the presence of electrowetting are examined. It has been shown that increasing the power-law index Increases the heat transfer. Also, shear-thinning fluids exhibit more dynamics. The results also suggest that an increase in the contact angle of chemical heterogeneity leads to increase in average Nusselt number. Finally, in larger microgrooves, the shear thickening fluids has the higher Prandtl and average Nusselt number.