Heat transfer and entropy generation analysis of electroosmotic flows in curved rectangular nanochannels considering the influence of steric effects

Abstract

The heat transfer characteristics and entropy generation of an electroosmotic flow in curved rectangular nanochannels under high zeta potential conditions are investigated numerically with consideration of the steric effects. The numerical solutions of the Nusselt number (Nu) and the local entropy generation rate (SG) are derived under constant wall heat flux assumption. The variation trends of Nu and SG with corresponding parameters, including the curvature ratio of the curved nanochannel (δ), the effective ionic size (a0) and the wall heat flux (qw) are investigated. Results reveal that, for small values of qw (qw < 10), the consideration of the steric effects (corresponding to a non zero assumption for a0) leads to a lower SG and an enhanced Nu simultaneously. In this case, to further reduce entropy generation, a curved nanochannel with a large curvature ratio δ is adopted. However, for relatively large values of qw, the steric effects will have a negative effect on entropy generation minimization, especially for a curved nanochannel with large curvature ratio. Our results may be useful in designing the efficient thermal nano-equipment.