Numerical investigation of laminar flow in square curved duct with 90 bend

Abstract

Numerical solution of incompressible laminar flow in square curved duct with 90 degree bend is performed in order to better understand the flow phenomena present in this type of flow. Simulation of flow was done in OpenFOAM, an open-source CFD software. Essentially, OpenFOAM is large C++ library which can be used to create application for solution of various problems in continuum mechanics. Besides object-oriented approach, the main advantage of OpenFOAM is that it is extendable, i.e. users can add their own applications and utilities. The solution for the flow investigated in this paper is for Reynolds number Re = 790. We used experimental results from literature as a validation tool for our simulation. The results of simulation showed very good agreement with experimental results. They also showed that centrifugal force convects the quickly moving fluid particles towards the outer wall. As a result, the axial velocity has peaks in curved region, and secondary flow with various number of vortices is also present. Development of flow in vertical straight section after the bend is also analyzed, where presence of swirl is detected.