Application of Cubic Eddy Viscosity Turbulence Models to 3D U-bend Duct Flows.

Abstract

This paper presents discussions on predicting turbulence and heat transfer in square sectioned 180° U-bend ducts whose curvature ratios are Rc/D=0.65 and 3.357. The low-Reynolds-number cubic nonlinear κ-ε and κ-ε-A2 turbulence models are applied for the flow field computation. In the thermal field computations, the higher order gradient diffusion heat flux model is applied in comparison with the standard models. The results suggest that the cubic nonlinear eddy viscosity and the higher order gradient diffusion heat flux models are very successful for predicting such three dimensional turbulence and heat transfer fields while some more modification in the models may be needed to capture heat transfer in the strongly curved case.