Local heat transfer in subcooled flow boiling in a vertical mini-gap channel

Abstract

An experimental study of subcooled flow boiling in a high-aspect-ratio, one-sided heating rectangular mini-gap channel was conducted using deionized water. The local heat transfer coefficient, onset of nucleate boiling (ONB), and flow pattern of subcooled boiling were investigated. The influence of heat flux and mass flux were studied with the aid of a high-speed camera. The bubbles were generated more quickly at higher heat flux and the diameters of departing bubbles decreased with increased flow mass flux. Partial dry-out and rewetting process caused by elongated bubble was also observed at lower mass flux. With the increase of heat flux, the surface near exit started boiling firstly, with more sharply increased heat transfer coefficient compared to the surface near entrance. The experimental heat transfer coefficients were analyzed using four existing

Experimentally Verified Flow Distribution Model for a Composite Modelling System

“…As for minigaps, such a single wide minichannel is a progressive option for dealing with high heat fluxes, mainly in electronic systems. Investigations into minigaps of different geometries (e.g., rectangular [21] or annular [22]) usually focus on the thermal performance (e.g., local heat transfer coefficients [23], Nusselt number [24], or temperature distribution [25]). Flow distribution in minigaps is discussed rarely, and if so, then usually as a side experimental observation [26] or in the form of numerical analyses using computational fluid dynamics (CFD) [27].…”