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

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. [ABSTRACT FROM AUTHOR]