A numerical investigation on the conjugate heat transfer of thin liquid film of water in closed microcavity

Abstract

The understanding of the conjugate heat transfer in an evaporating thin-film and an intrinsic meniscus is important for enhancing the thermal performance of phase-change heat transfer devices. In this paper, we numerically investigated the conjugate heat transfer in the thin film and the intrinsic meniscus under their own vapor in closed microcavities with different geometries. The results show that, with decreasing microcavity size, the percentage contribution of the thin liquid film to the overall heat transfer increases obviously. However, in order to optimally utilize the thin-film heat transfer, both the microcavity size and the length-height ratio need to be concerned for their effects on the thin-film contribution to the net heat transfer. With increasing superheats that are smaller than 5 K, the contribution of the thin film to the net heat transfer rate becomes somewhat smaller, although the variation seems to be less sensitive to the superheat than the microcavity size. Meanwhile, when the wettability improves, the contribution of the thin film to the net heat transfer rate increases, but the variation of the thin-film contribution is relatively less sensitive to the wettability than the microcavity size and the superheat.