Experimental flow boiling study in a 0.52 mm diameter vertical tube using R134a

Abstract

Experimental results for R134a boiling on a vertical stainless steel tube of internal diameter 0.52 mm are presented in this paper. They form part of an ongoing study of flow boiling in a wide range of small diameter tubes. Other parameters were varied in the range: mass flux 300-700 kg/m2.s; heat flux 1.6-75 kW/m2 and pressure 6 -10 bar. The flow patterns visualised at the exit of the heated test section are first presented. The variation of the heat transfer coefficient with thermodynamic quality and its dependence on heat flux, mass flux and system pressure is then presented and discussed.