Numerical Simulations of Turbulent Flow Through a 90-Deg Pipe Bend

Abstract

The turbulent flow through a 90-deg circular pipe bend is investigated by carrying out the numerical simulations using the Reynolds-averaged Navier–Stokes (RANS) turbulence model in the present study. The objective of the present study is to evaluate the effects of different values of the curvature radius (Rc) and different Reynolds numbers (Re) on the flow development in the circular pipe bend by employing the explicit algebraic Reynolds stress model (EARSM) to resolve the Reynolds stresses, unlike the research carried out so far where the turbulence anisotropy has not been considered. The curvature ratio defined as the curvature radius to pipe diameter (Rc/D) is varied between 1 and 4 and the investigated Re range is from 10,000 to 60,000. The numerical model is validated by comparing the axial velocity profiles with the previous published experimental data. It is found that for the fixed Re and decreasing Rc/D, the axial velocity, the velocity perturbation, and the pressure difference in the cross section increase and vorticity becomes stronger. When the curvature ratio gets smaller than 2, the flow velocity profile becomes highly distorted. For the fixed Rc/D, the influence of the Re on the flow behavior is small for the investigated range of Re.