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

• Published in: Computers & fluids 2014-07, Vol.99, p.116-123
• Main Authors: Csizmadia, Péter, Hős, Csaba
• Format: Article
• Language: English
• Subjects: CFD; Coefficients; Computational fluid dynamics; Diffuser; Diffusers; Elbow; Fluid flow; Fluids; Loss coefficient; Mathematical models; Non-Newtonian fluid; Turbulence; Turbulent flow
• ISSN: 0045-7930; 1879-0747
• DOI: 10.1016/j.compfluid.2014.04.004

•The non-Newtonian flow in diffusers and elbows of different geometries are studied.•Loss coefficients are reported for power-law and Bingham fluid for pipeline fittings.•The flow field is computed with CFD technique validated by measurements.•The performance of turbulence models for non-Newtonian fluids is studied. 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.