Local jet impingement boiling heat transfer

Abstract

This study focuses on some of the fundamental issues that influence boiling heat transfer to a free-surface, planar jet of water. Local boiling curves are presented at several streamwise distances from the stagnation line, while streamwise distributions of the surface temperature and convection coefficient are presented for representative heat fluxes. The position downstream of the stagnation line strongly influences heat transfer in the single-phase convection regime, has no appreciable effect on fully-developed nucleate boiling, but does influence the extent of the partial boiling regime. The effect of jet velocity on heat transfer is most pronounced in the single-phase and partial boiling regimes, where convective transport is dominated by the hydrodynamics of the bulk flow, and not by evaporation or bubble motion. Within the fully-developed boiling regime, the convective transport is dominated by evaporation and intense mixing induced by bubbles leaving the surface, and heat transfer is insensitive to jet velocity.