Enhancement of heat transfer in subcooled flow boiling with microbubble emission

Abstract: Subcooled flow boiling of water was tested for a large heating surface of 5cm length and 2cm width in a horizontal rectangular channel of 5mm height and 24mm width. Microbubble emission boiling occurred in transition boiling at 40K of liquid subcooling and 0.5m/s of liquid velocity and the maximum heat flux was higher than the ordinary critical heat flux. Maximum heat flux obtained was 5MW/m2. In subcooled pool boiling of alcohol–water mixtures, critical heat fluxes were higher than that of water, especially, polyhydric alcohol–water mixtures such as 1-butanol and 2-propanol showed about 50% higher critical heat fluxes than water. In the subcooled flow boiling with small heating surface of 10mm×10mm, microbubble emission boiling occurred in transition boiling and the maximum heat fluxes were 10% higher than the water. [Copyright &y& Elsevier]