Experimental Investigation of Flow Boiling in a Vertical Narrow Channel

Experimental investigations on thermofluid-dynamic phenomena in a vertical narrow rectangular microchannel with the hydraulic diameter d_h = 0.27 mm were carried out. The experiments are performed under fluid-inlet subcooling conditions with de-ionised and degassed water for different mass fluxes (50–2000 kg/m²s) and heat fluxes (2–150 kW/m²). Moreover, flow visualisation of the two-phase flow patterns along the channel is performed using a digital high-speed video camera. Investigations on pressure drop during single- and two-phase flow have been carried out. The present work is concentrated on two-phase heat transfer. The mean heat transfer coefficient and the local heat transfer coefficient at saturated conditions were calculated and the latter ones was compared with available correlations.