Implementation of Non-Newtonian Fluid Properties for Compressible Multiphase Flows in OpenFOAM

Stefan Westermaier,Wojciech Kowalczyk

doi:10.4236/ojfd.2020.102009

Abstract

The paper presents the implementation of non-Newtonian fluid properties for compressible multiphase solver in the open source framework OpenFOAM. The transport models for Power Law, Cross Power Law, Casson, Bird-Carreau and Herschel-Bulkley fluids were included in the thermophysical model library. Appropriate non-Newtonian liquids have been chosen from literature, and pressure driven test simulations are carried out. Therefore, the solver compressibleInterFoam is used to compute air-liquid mixture flows over a backward facing step. A validation of the novel models has been performed by means of a sample-based comparison of the strain rate viscosity relation. The theoretical rheological properties of the selected liquids agree well with the results of the simulated data.

Highlights

Non-Newtonian liquids are part of almost all areas of our daily life, such as toothpaste, ketchup, concrete, lubrication oils, polymer melts or blood, to name just a few
The results show a physically consistent viscosity variation related to the local velocity gradient for the non-Newtonian liquids and a constant viscosity for water
The main objective of the presented work was the allocation of non-Newtonian models for compressible multiphase solver in OpenFOAM

Summary

Introduction

Non-Newtonian liquids are part of almost all areas of our daily life, such as toothpaste, ketchup, concrete, lubrication oils, polymer melts or blood, to name just a few. In terms of process engineering and transport processes, flows of non-Newtonian fluids frequently occur in combination with compressible media (e.g. polyethylene foam and protein foam). This field is of great interest for scientific research. Different numerical models and techniques for non-Newtonian multiphase flows were developed and implemented in open source software already. In this context, Sawko [7] implemented a modified approach for wall modeling in pipes and channels and Habla et al [8] created a solver for viscoelastic two-phase flows. Numerical instabilities concerning the high Weissenberg number problem or stability issues caused by surface tensions were some of the objectives of the method proposed in [11]

Objectives

Methods

Results

Conclusion