CFD-based estimation and experiments on the loss coefficient for Bingham and power-law fluids through diffusers and elbows

Abstract

This paper presents results on the CFD-based estimation of loss coefficients for typical pipeline elements in the case of Bingham and power law fluids. The actual elements are diffusers with angles between 7.5° and 40° and elbows of R/D ratios between 1 and 10. Three fluids were studied; water (for validation purposes), a power-law fluid (0.13m/m% Carbopol 971 solution) and Bingham plastic fluids with Hedström number varying from 10 to 106. Experiments were conducted with water and power-law fluid to validate the CFD computations. Loss coefficients are given for the Reynolds number regime that is usual in engineering applications. The behavior of different turbulence models (eddy-viscosity and Reynolds stress models) are also reported.