CHARACTERISTICS OF SECONDARY FLOW INDUCED BY 90-DEGREE ELBOW IN TURBULENT PIPE FLOW

The purpose of this study is to characterize the swirling secondary flow in the downstream of a pipe bend using a numerical simulation of the flow. The CFD (Computational Fluid Dynamics) software OpenFOAM is used to simulate the turbulent flow in pipes with elbow. Various turbulence models are benchmarked with the existing experimental data and a comparative study is performed to select an appropriate turbulence model for the analysis. Predictions made by the selected turbulence model are compared with the LDA (Laser Doppler anemometer) measurements from the experiments currently conducted to find the dependency of the flows on the Reynolds number. It is found that the swirl intensity of the secondary flow is a strong function of the radius of curvature of the bend and a weak function of the Reynolds number. Additionally, it is found that the dissipation of the swirl intensity is exponential in nature.