Heat Transfer Characteristic and Critical Heat Flux in Mist Dispersed Flow

The heat transfer in mist cooling for low droplet density, focusing on the heat transfer characteristics, behaviors of liquid on a heating surface and measurements of liquid droplets by LDA was investigated experimentally. Steady heat transfer experiments of a copper block were conducted for mist flow of air and water in a range of air flow rate from 40 to 120 1_N/min. Water flow rate was 0.3, 0.9, 1.8, 4.0 and 8.0 1/hr, respectively. Mist flow of water and air forming in a fully conical nozzle with a mixture camber was supplied on the heating surface arranged for horizontal-upward position. The critical heat flux increased with an increasing liquid flow rate. The critical heat flux decreased as the air flow rate increased. Three correlations of the mist cooling rate for non-boiling, evaporation of droplets and evaporation of the liquid film were developed with microscopic parameters of two-phase flow, respectively.