Investigation of heat transfer and pressure drop in a concentric heat exchanger with snail entrance

Durmuş A., Durmuş A., Esen M.

Applied Thermal Engineering, cilt.22, sa.3, ss.321-332, 2002 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 22 Sayı: 3
  • Basım Tarihi: 2002
  • Doi Numarası: 10.1016/s1359-4311(01)00078-3
  • Dergi Adı: Applied Thermal Engineering
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.321-332
  • Anahtar Kelimeler: Concentric heat exchanger, Experimental, Heat transfer enhancement, Pumping power, Snail, Swirl flow, Swirling angle
  • Ondokuz Mayıs Üniversitesi Adresli: Hayır

Özet

In this study, in order to increase heat transfer in concentric double-pipe heat exchangers by passive method, snail which is mounted at inlet of the inner pipe and assumed as a swirl generator was used. In the experimental set-up, cold air in ambient conditions was passed through the inner pipe while hot water was flowing through the annulus. The effects of a snail on the heat transfer and pressure drop were investigated for parallel and counter-flow, and obtained Nusselt numbers (Nu) were compared with those found, using a standard correlation such as Dittus-Boelter equation given for axial flows in smooth pipes. The results were correlated in the form of Nusselt number as a function of Reynolds number, Prandtl number and the swirling angle. An augmentation of up to 120% in Nusselt number was obtained in the swirl flow for counter-flow and 45° swirling angle. Though the swirl flow effect of the snail caused some increase in pressure drop, this effect was unimportant compared with the improvement in heat transfer capacity. © 2002 Elsevier Science Ltd. All rights reserved.