COMPOUND HEAT TRANSFER ENHANCEMENT OF A CONVERGING-DIVERGING TUBE WITH REGULARLY SPACED TWISTED-TAPE INSERTS

摘要：

A compound heat transfer enhancement mechanism is presented. Pressure drop and heat transfer characteristics of a converging-diverging tube inserted with spaced twisted-tapes have been investigated experimentally. The swirl flow was generated by spaced twisted-tape elements which vary in twist ratio y and rotation angle θ. Twisted-tape pitch Lp also has an important effect on the characteristics. For comparison, experiments in a smooth tube were carried out. The results show that the valuation factor of heat transfer enhancement, which is influenced more strongly by twist ratio than by rotation angle, increases as the Reynolds number increases. The twisted-tape with twist ratio y=4.72 and rotation angle θ=180° has the best performance in three types of twisted-tapes presented in the paper. In the highest Reynolds number (Re=19000～20000), when the twisted-tape pitch Lp=700 mm, the heat transfer enhancement valuation factor increases 21％ over that in the case of smooth tube.

作者: M.HONG X.DENG Z.LI

作者单位: The Key Laboratory of Enhanced Heat Transfer and Energy Conservation of Education Ministry, School of Chemical and Energy Engineering, South China University of Technology, Wushan Road, Guangzhou, 510640, China

会议类型: 国际会议

会议名称: The 22nd International Congress of Refrigeration(第22届国际制冷大会)

会议地点: 北京

会议语种:英文

在线出版日期: 2007-08-21（万方平台首次上网日期，不代表论文的发表时间）