Direct measurement of local heat flux during flow boiling in a minichannel

Abstract

Heat transfer characteristics of water flow boiling in a minichannel were investigated through the direct measurement of local heat flux using a developed MEMS heat flux sensor with a multi-layered structure. The measurement results clearly indicated the fundamental heat transfer processes including thin liquid film evaporation, dry-out of the liquid film, transient heat conduction after rewetting of the dry-patch, and single phase forced convection. From the obtained local heat flux, the contribution of each fundamental heat transfer process to the overall wall heat transfer was evaluated. The thin liquid film evaporation was the dominant heat transfer mechanism in the wide range of experimental conditions.