Pressure Drop Oscillations and Flow Patterns for Flow Boiling of Water in Narrow Channels

摘要

Experimental investigation on the flow boiling in the narrow vertical channels is conducted. Two rectangular channels with the size of 2x4 mm~2 and 0.5x2.0 mm~2 (widthxdepth), corresponding hydraulic diameters are 2.67 mm and 0.8 mm, are employed. Deionized water is the working fluid. Through steady state experiments, the effect of heat flux, mass flux and inlet subcooling on pressure drop and heat transfer in narrow channels is obtained. Flow patterns and the transition of flow patterns along the channel axis are observed through a video-camera. Bubbly flow, slug flow and annular flow are distinguished in two channels. Furthermore, dynamic features of pressure drop oscillations are also involved.