Augmentation of Laminar Flow Heat Transfer in Annular Flat Tubes by Means of Helical Screw-tape Inserts in the Inner Tube. | ||||
| MEJ- Mansoura Engineering Journal | ||||
| Article 10, Volume 34, Issue 3, September 2009, Page 44-71 PDF (618.44 K) | ||||
| Document Type: Research Studies | ||||
| DOI: 10.21608/bfemu.2021.157717 | ||||
 View on SCiNiTO | ||||
| Author | ||||
Emad Zidan Ibrahim 
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| Professor of Mechanical Power Engineering Department., Faculty of Engineering., Zagazig University., Zagazig., Egypt. | ||||
| Abstract | ||||
| The heat transfer characteristics and friction factor in horizontal double pipes of flat tubes with full length helical screw element of different twist ratio and helical screw inserts with different spacer length are investigated. Cold and hot water are used as working fluid in tube side and shell side respectively. The experiments covered a range of Reynolds numbers 5.7*102 ≤ Re ≤ 1.31*103. The effect of spacer length and twist ratio on the heat transfer augmentation and friction factor on heat transfer have been presented separately. The study shows that, Nusslet number (Nu) and friction factor (f) decrease with the increase of spacer length (S) and twist ratio (Y) for flat tube. The comparison between the data of present plain circular tube with that of previous plain circular tubes showed good agreement but the data of present plain flat tube showed a higher in heat transfer and pressure drop than that of plain circular tube. The correlations of average Nusselt number and friction factor with Re, S and Y are presented. | ||||
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