Electrodeposited porous surfaces with capillary effect for enhancing the heat transfer performance of Novec-7100 in spray cooling

Abstract

This study investigated the spray cooling performance of Novec-7100 on electrodeposited copper surfaces. Test surfaces with microporous structures were fabricated using a two-step electrodeposition method. Different current densities (i.e., 0.3, 0.5, and 1.5 A/cm²) were applied to produce microporous structures with distinct surface properties. The results of this study indicated that the capillary effect of these microporous structures enhanced the heat transfer performance. In the single-phase heat transfer regime, the heat transfer coefficients of the electrodeposited surfaces, which had microporous structures, were higher than that of a plain copper surface. This is because the electrodeposited surfaces had a larger evaporation area, a longer triple-contact line, and stronger droplet impact convection. In the two-phase heat transfer regime, the microporous structures of the electrodeposited surfaces had more numerous sites available for surface and secondary nucleation. Furthermore, the electrodeposited surface that was produced under a current density of 1.5 A/cm² exhibited the best capillary performance; its heat transfer coefficient and critical heat flux were increased by 62% and 66% compared to the plain surface, respectively. Finally, the heat transfer data collected in the single- and two-phase regimes were correlated using modified prediction models incorporating a dimensionless capillary parameter. The errors in the predictions of the models derived for these regimes were within 11.5% and 28%, respectively.