TWO -PHASE FRICTION PRESSURE DROP OF SMALL DIAMETER U-TYPE WAVY PIPES

Measured frictional pressure drops for single -phase water and two -phase air -water mixture flowing in nine small diameter U-type wavy tubes were presented. The inner diameters of the wavy tube s are 3. 43 - 8.29 mm, whereas the curvature ratio s span from 3.75~7.87 . T est range of the Reynolds number for the single -phase water tests is about 200 400 kg/m 2 �s and Martinelli