Mixed and forced convection heat transfer in baffled channels. A brief review

Document Type : Review Article

Authors

1 Faculty of technology, University of Medea, Algeria

2 Faculty of Technology, University of Medea, Algeia

Abstract

Improving heat transfer in thermal systems has become a focus of many research studies due to the critical need for efficient waste of residual heat. The regulation of heat transfer between components in thermal systems has a direct impact on their efficiency and performance. As a result, effective heat management is critical to improving the efficiency of thermal systems and extending the life of their components. It should be noticed that baffles are important structural components widely used in various industrial applications like heat exchangers, solar collectors, electronic cooling, etc. In addition, baffles enhance fluid mixing and heat transfer behaviors. Most industrial systems do not operate in a steady state. In particular, transient phases occur during start-up and shut-down, or during the control phase of controlled systems. Thus, in laminar flow, baffles induce flow unsteadiness or help the flow to bifurcate from steady state to unsteady flow. This paper treated the effects of different baffle shapes incorporated in channels on heat transfer rate, efficiency and friction factor in mixed and forced convection cases. Various experimental and numerical studies have been carried out in this topic to examine heat transfer enhancement compared to the flow energy. It was noticed that increasing Reynolds number, blockage ratio and decreasing Grashof number can achieve an increase in heat transfer. The maximum heat transfer enhancement was obtained for higher blockage ratio and higher Reynolds number in forced convective flow. The highest heat transfer improvement was obtained for the 45° angled baffles (between 150% and 850%). In mixed convective flow, the highest rate of heat transfer was obtained for transverse baffles (2.8 times compared to the similar channel with no baffles). Finally, This comprehensive review is beneficial for researchers focused on flow and heat transfer applications to use other baffle designs and fluids beyond air.

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Articles in Press, Accepted Manuscript
Available Online from 22 August 2024
  • Receive Date: 07 June 2024
  • Revise Date: 19 August 2024
  • Accept Date: 22 August 2024