Eventos Anais de eventos
ENCIT 2018
Brazilian Congress of Thermal Sciences and Engineering
Numerical Simulation of Extrudate Swell of Oldroyd-B Fluids
Submission Author:
Caroline Viezel , SP
Co-Authors:
Caroline Viezel, Murilo Tomé
Presenter: Caroline Viezel
doi://10.26678/ABCM.ENCIT2018.CIT18-0820
Abstract
The objective of this work is to present numerical results of the extrudate swell problem of Oldroyd-B fluids employing arbitrary viscosity ratios in [0, 1]. To this effect, we formulated a finite difference method to solve the governing equations whereby the mass conservation, momentum and constitutive equations are solved implicitly on a staggered mesh. In this work, the extra-stress tensor is computed via the conformation tensor which is solved by a semi-implicit method while the implicit Euler method is applied to solve the momentum equation. Analytic solutions for steady state tube flow are used to verify the Oldroyd-B code. To demonstrate the convergence of the numerical method on free surface flows, the extrudate swell was simulated on several refined meshes and details of the numerical solutions are presented. Moreover, by making viscosity ratios to zero, the convergence of the Oldroyd-B model to the Upper-Convected-Maxwell model, on this complex free surface flow problem, is demonstrated.
Keywords
Die-swell, Oldroyd-B model, EVSS transformation, Conformation tensor, Finite difference
