The Effect of Inlet Baffle on the Skin Friction Coefficient and Turbulence Intensity in an Air-Cooled Channel

Abstract

This study addresses the impact of an inlet baffle mounted opposite a hot surface on the properties of turbulence and flow resistance in an air-cooled channel. This study focuses on analyzing the variation in the skin friction coefficient and air turbulence intensity along the hot surface. The influence of an inclined baffle angle α = 15−60° and relative baffle length Ln = 0.625−0.875 under the Reynolds number spectrum Re = 4000−16000 was considered. Results indicated that turbulence intensity increased when the Reynolds number increased, the baffle length increased, or the inclined baffle angle decreased. The skin friction coefficient increased when the Reynolds number decreased, the baffle length increased, or the inclined baffle angle decreased. The maximum heat transfer rate occurs at α = 15°, Ln = 0.875, and Re = 16000, and vice versa at α = 60°, Ln = 0.625, and Re = 4000. In comparing the lowest and highest heat transfer configurations, the skin friction coefficient decreased by 77.9 %, and turbulence intensity decreased by 97 %. This means that heat transfer can be increased at the cost of higher pump power. The results of this study contribute to a more comprehensive understanding of the effect of an inlet baffle on fluid chaotic motion and flow resistance, as well as the mechanism that leads to the variation in heat transfer ability and pressure loss in the channel under the impact of the inlet baffle.

Keywords

• Inlet baffle
• Air-cooled channel
• Skin friction coefficient
• Turbulence intensity

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