Numerical Investigation of Turbulent Heat Transfer in a Rectangular-Sectioned 90° Bend

ABSTRACT

The flow and thermal fields in a rectangular-sectioned 90° bend with a cross-section aspect ratio of 6 were investigated using four turbulence models. All models managed to reproduce the general flow and thermal patterns. Chen's high-Re k–ϵ model and Suga's cubic low-Re k–ϵ model performed well. The V2F k–ϵ model was found to be the least diffusive model and delivered good results. The RSM-GGDH model showed convergence difficulties and gave poor results. It was found that the boundary-layer thickness and the flow upstream of the bend are crucial for the character of the secondary flow, velocity profile, turbulence level, and heat transfer in the bend.

The authors would like to acknowledge Lic. Engn. Olof Daunius, Volvo Car Corporation, for much valuable discussion and advice. This study is financed by the Swedish Agency for Innovation Systems (VINNOVA) and Volvo Car Corporation.