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Indexed by:期刊论文

Date of Publication:2018-06-01

Journal:DESALINATION AND WATER TREATMENT

Included Journals:SCIE

Volume:118

Page Number:61-69

ISSN No.:1944-3994

Key Words:Horizontal tube falling film; Flow pattern; Critical transition Reynolds; Hysteresis phenomenon

Abstract:Inter-tube flow pattern of horizontal tube falling film dominates the flow state of thin film around the tube and influences heat transfer. An observation experiment was performed to investigate the intertube flow characteristics of horizontal tube falling film focusing on 19 and 25.4 mm-diameter Al-brass tubes with the Reynolds number ranging from 64.4 to 598. The flow pattern images were captured by a high-definition camera and a high-speed camera with backlight method. Flow patterns were characterized and their transitions were classified. Phenomena occurred in flow pattern transition were discussed with the variation of Reynolds number, tube spacing, and tube diameter. The results show that the critical transition Reynolds number increases with tube spacing. Special flow patterns were observed and classified when the tube spacing was undersize. The hysteresis in horizontal tube falling film flow were discussed in detailed.