Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
EVALUATING RANS TURBULENCE MODELS TO PREDICT THE AIRFLOW IN A DUCT BEND
Submission Author:
Marcos Batistella Lopes , PR
Co-Authors:
Marcos Batistella Lopes, Viviana Mariani, katia cordeiro, Claudine BEGHEIN
Presenter: Marcos Batistella Lopes
doi://10.26678/ABCM.ENCIT2018.CIT18-0026
Abstract
The main objective of this study is to evaluate the accuracy of some Reynolds Averaged Navier-Stokes (RANS) models to predict the behavior of the turbulent flows in a horizontal circular duct bend. The selection of the RANS models tested follows the capability of each model to describe the Low Reynolds Number (LRN) flows, i.e., the flow near the wall. Therefore, five turbulence models were selected: three Eddy Viscosity Models (two linear, k-ω SST and LRN k-ε of Launder and Sharma, and one non-linear, cubic k-ε of Lien) and two Reynolds Stress Models (LRR and SSG). The numerical solutions were carried out using Computational Fluid Dynamics (CFD) code OpenFOAM® applied in an incompressible turbulent viscous flow. The grid discretization of the viscous sublayer leads to a refinement near to the walls and a smooth grid expansion ratio from the wall to the core of the pipe. The air flows with a Reynolds number of 6×104 through a straight circular duct of 0.104 m diameter followed by a 90° bend with curvature ratio of 4. The principal results were compared in terms of streamwise mean velocity profile and turbulence intensity contours. The turbulence models that performed better according to the velocity fields and turbulence intensity was the SSG. Nevertheless, none of them were able to accurately predict the flow next to the inner wall at the bend outlet.
Keywords
duct bend, CFD, turbulence modeling, RANS
