Evaluation eddy-viscosity turbulence models to predict the airflow in elbows

The objective of this work is to evaluate the capability of eddy-viscosity models to describe the behaviour of the flow in elbows. The experimental study from Sudo et al. (1998), in which the air flows with a Reynolds number of 6×104 through a circular duct of 0.104 m diameter followed by a 90-deg bend of curvature ratio equals 4, served as benchmark for the aimed analysis. Six turbulence models, k-ω, k-ω SST, LRN k-ε of Launder and Sharma, LRN k-ε of Lien and Leschziner, V2f and cubic k-ε of Lien, were compared in terms of mean velocity profiles and turbulence intensity contours. The turbulence models that performed better according to the adopted criteria were the k-ω SST, the LRN k-ε of Launder and Sharma and LRN k-ε of Lien and Leschziner. Although, none of them neither the other turbulence models tested were able to predict satisfactory the flow next to the inner wall at the bend outlet (90°).