Heat Transfer Potentiality and Flow Behavior in a Square Duct Fitted with Double-Inclined Baffles: A Numerical Analysis

Parviz Ghadimi,Withada Jedsadaratanachai,Amnart Boonloi

doi:10.1155/2021/9957126

Abstract

Numerical analysis of heat transfer mechanisms and flow topologies for the heat exchanger square channel (HESC) installed with the double-inclined baffles (DIB) is reported. The main objective of the present research is to study the influences of DIB height to duct height ( b / H = 0.05 – 0.30 ), DIB distance to duct height ( P / H = 1 – 1.5 ), and flow attack angle ( α = 30 ° and 45 ° ) on the flow topologies, heat transfer features, and thermal performances. The Reynolds numbers (based on the entry HESC around 100–2000) are analyzed for the present problem. The numerical models of the HESC installed with the DIB are solved with finite volume method (commercial code). The simulated results of the HESC installed with the DIB are reported in forms of flow topologies and heat transfer characteristics. The Nusselt numbers (Nu), friction factors ( f ), and thermal enhancement factors (TEF) of the HESC placed with the DIB are offered. As the numerical results, it is seen that the DIB produces the vortex streams and impinging streams in all cases. The vortex streams and impinging streams disturb the thermal boundary layer on the HESC walls that is a key motive for the growth of heat transfer rate. The best TEF of the HESC installed with the DIB is about 3.87 at P / H = 1 , α = 30 ° , Re = 2000 , and b / H = 0.15 . Additionally, the TEF contours, which help to design the HESC inserted with the DIB, are performed.

Highlights

Thermal development for production processes of many plants and engineering devices has been investigated by various research groups
The numerical analysis on heat transfer potentiality, pressure loss, and thermo-hydraulic performance in the heat exchanger square channel (HESC) installed with the double-inclined baffles (DIB) is performed
The vortex streams and impinging streams are a disruptor of thermal boundary layer on the HESC surfaces

Summary

Introduction

Thermal development for production processes of many plants and engineering devices has been investigated by various research groups. The thermal development can be done by both passive and active techniques. The passive technique is an installation of turbulators or vortex generators in heat exchangers to produce vortex streams and impinging streams through heating/cooling sections. The vortex streams and impinging streams influence for a change of thermal boundary layer that is a main reason for heat transfer enhancement. The vortex streams and impinging streams grow fluid mixing power that is another cause for the heat transfer improvement. The active method is an addition of external power into heating/cooling processes to grow heat transfer rates. The active technique has great efficiency to extend heat transfer ability in the heat exchangers. The passive technique is picked to extend the heat transfer ability and thermal performance in the heat exchanger duct

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Conclusion