Prediction Method of Flow Patterns in Subcooled and Low Quality Boiling Regions

Abstract

A new parameter is proposed for prediction of the transition between flow patterns such as bubble, froth and annular flow, in both the subcooled and low quality regions of boiling flow. This parameter is derived from the theoretical calculation method of void fraction, which has been reported, on the assumption that the flow pattern transition occurs at a value of average void fraction over the cross section of the flow. A flow map is also presented which reasonably correlates the experimental results covering the following conditions ; pressure : 1∼98 ata, heat flux : 2×10⁴∼5×10⁶kcal/m²h, and mass velocity : 40∼5400kg/m²s.