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Numerical investigation of different geometrical parameters of perforated conical rings on flow structure and heat transfer in heat exchangers

Erfanian Nakhchi, M ; Sharif University of Technology | 2019

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  1. Type of Document: Article
  2. DOI: 10.1016/j.applthermaleng.2019.04.067
  3. Publisher: Elsevier Ltd , 2019
  4. Abstract:
  5. A numerical study has been performed to investigate the flow and heat transfer characteristics of fluid flow through heat exchanger tubes fitted with perforated conical rings. The holes are circular, and the number of holes N is ranged from 0 to 10. The influences of perforated conical ring diameter ratios D2/D1=0.4,0.5and0.6 and the hole diameter ratios d/D=0.06,0.1and0.14 on average Nusselt number, friction factor and thermal performance factor are reported. This analysis is performed in the turbulent flow regime 4000⩽Re⩽14,000 and the governing equations are solved by using (RNG) k-∊ model. Due to strong turbulent intensity, perforated conical rings lead to more flow perturbation and fluid mixing between walls and the core region, which has a significant effect on heat transfer enhancement. The recirculating flow through the holes can also improve the heat transfer and reduce the pressure drop through the heat exchanger tube. The results show that the Nusselt number is reduced up to 35.48% by increasing the number of holes from 4 to 10. The maximum thermal performance factor of 1.241 is obtained for the case of N=10, d/D=0.1 and D2/D1=0.6 at Reynolds number of 4000
  6. Keywords:
  7. Heat exchanger tube ; Perforated conical ring ; Recirculating flow ; Thermal performance ; Flow of fluids ; Geometry ; Nusselt number ; Reynolds number ; Flow and heat transfer ; Heat exchanger tube ; Heat Transfer enhancement ; Numerical investigations ; Recirculating flow ; Thermal Performance ; Thermal performance factors ; Turbulent intensities ; Heat exchangers
  8. Source: Applied Thermal Engineering ; Volume 156 , 2019 , Pages 494-505 ; 13594311 (ISSN)
  9. URL: https://www.sciencedirect.com/science/article/abs/pii/S1359431118366328