ISSN Online: 2377-424X
ISBN Print: 0-89116-299-2
International Heat Transfer Conference 7
BUBBLY-FLOW HEAT TRANSFER DOWNSTREAM OF A BLOCKAGE IN A RECTANGULAR CHANNEL
摘要
This paper deals with the experimental results of two-phase air-water flow and heat transfer downstream of a wall-attached blockage in a vertical rectangular channel with a cross section of 100×20 mm. The blockage ratio was varied from 0.4 to 0.8. The liquid Reynolds number (Re1) ranged 8300-33000. The quality was varied from 2×10−5 to 4×l0−4 in bubbly flow regime. In low Rex and small blockages, the introduction of air into water enhanced the heat transfer along the total channel length. In high Re Re1 and big blockages, however, two-phase flow was disturbed by the blockage and bubbles were fragmented into many fine particles. These fine bubbles weakened the flow reattaching to the wall downstream of the separation zone, resulting in lowering the peak Nusselt number which appeared at the reattaching point.