Numerical Studies on Turbulent Flow Field in a 90 deg Pipe Bend

Abstract

This paper deals with the modeling of turbulent flow through a 90 deg pipe bend using an unsteady Reynolds-averaged Navier–Stokes (U-RANS) approach where k–ε model is used for turbulence closure. While limitations in solving complex flows of the k–ε model have been reported in the literature, this study demonstrates that for pipe flows with curvature, the k–ε model performs reasonably well. Investigations have been carried out to find out the influence of Reynolds number (Re) and bend curvature ratio (Rc/D) on turbulent flow parameters, namely, instantaneous axial velocity, turbulent kinetic energy, turbulent intensity, and wall shear stress. Bend curvature is found to strongly influence the turbulent flow characteristics, while no such high Reynolds number dependency is observed in this study range. In general, this paper presents a computationally cost-effective numerical study on the time averaged turbulent flow field in a 90 deg pipe bend, which may be used for the design and development of 90 deg pipe bends at a high Reynolds number regime.