ارزيابي عملكرد نوارهاي پيچيده شده در افزايش انتقال حرارت چگالشي و تاثير آن بر ميزان افت فشار

Evaluation of Twisted Tapes Performance in Enhancement of Condensing Heat Transfer and Pressure Drop

In this research, heat transfer enhancement and simultaneous effect of that on pressure drop inside condensers with twisted tape inserts are investigated. A refrigeration system is designed for attaining to maximum level of heat transfer with minimum pressure drop. The test condenser is a double pipe heat transformer with inner and outer diameter of 10.7mm and 12.7mm for internal pipe, respectively. The test tubeʹs length is 104mm. Experiments are performed for a plain tube and four tubes with twisted tape inserts with different twist ratios of 6, 9, 12 and 15. Also data are collected for mass velocities of 56.44, 69.49, 82.38, 96.52, 113.32 and 130.9kg/m2s. In conclusion, data analysis showed that insertion of twisted tapes inside tubes has increased the heat transfer and pressure drop by as much as 40% and 240% above the plain tube values on a nominal area basis, respectively.