Mass and Heat Transfer Characteristics for Laminar Flow in a Sharp 180° Turn. | ||||
| MEJ- Mansoura Engineering Journal | ||||
| Article 20, Volume 31, Issue 1, March 2006, Page 25-41 PDF (1.34 MB) | ||||
| Document Type: Research Studies | ||||
| DOI: 10.21608/bfemu.2020.129420 | ||||
 View on SCiNiTO | ||||
| Author | ||||
M. Safwat Mohamed 
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| Mechanical Power Engineering Department, Faculty of Engineering, Mansoura University, Mansoura, Egypt | ||||
| Abstract | ||||
| Numerical studies of laminar flow and heat transfer around a sharp 180° turn, of especial relevance to electronic systems, are made. Two-dimensional unsteady simulations are considered because of the high geometrical aspect ratios (AR > 5) occurring in the practical application. A high-order time-accurate finite volume scheme was used to solve unsteady incompressible Navier-Stokes and energy equations. Simulations are performed for 50 ≤ Re ≤1000. Predictions show that the sharp tum flow remains steady up to Re ≤ 600. In this steady regime, the re-attachment length increases gradually with the Reynolds number. However, a further increase in the Reynolds number gives rise to oscillatory flow because of the large-scale vortices emanating from the sharp edge. These vortices dominate the flow field. Oscillations cause a considerable reduction in the re-attachment length and a significant increase in convective heat transfer. The correlation between the local beat transfer and the flow field is examined. Instantaneous friction coefficient and Nusselt number Nu variations show that local heat transfer distributions correlate closely with the flow fields. | ||||
| Keywords | ||||
| Sharp 180° turn, Numerical simulation, Laminar; Oscillatory flow, Heat transfer | ||||
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