Experimental study of flow characteristics during condensation in narrow channels:: the influence of the diameter channel on structure patterns

The convective condensation in tubes of various dimensions has been studied experimentally, providing visual data on the condensation flow patterns for three tubes with inner diameters of 10, 1.1 and 0.56 mm. By means of a high speed camera, flow can be divided into three zones: an annular zone, a zone of Taylor's bubbles and a zone with isolated spherical collapsing bubbles. The effect of gravity on the flow patterns is highlighted and our experimental results on flow structures are compared with the descriptions and characteristics found in the literature. Finally, flow laws have been established thanks to the measurement of pressure drops. (C) 2004 Elsevier Ltd. All rights reserved.