Eulerian Flow Between 2 Concentric Cylinders

Non-Newtonian Flow Between 2 Concentric Cylinders (Eulerian) — ANSYS Fluent CFD Simulation

Description

This project presents a CFD simulation of two-phase non-Newtonian flow between two concentric cylinders — a benchmark geometry used across drilling engineering, polymer processing, biomedical devices, and food technology. Unlike Newtonian fluids such as water or air, non-Newtonian fluids change their viscosity in response to applied shear, and capturing that behavior correctly is critical for accurate predictions. In this project, you'll model a Power-Law non-Newtonian base fluid (k = 0.021, n = 0.75) flowing through an annular channel with a rotating inner cylinder, while a denser soluble secondary phase travels through it using the Eulerian multiphase model. As the opening project of the Non-Newtonian Flow: Beginner CFD Training Package, it introduces the core idea of shear-dependent viscosity in the simplest, most fundamental geometry — the concentric annulus.

Methodology

The 3D annular geometry (1 m length, 0.0225 m inner diameter, 0.03125 m outer diameter) is designed in Design Modeler and meshed in ANSYS Meshing with a structured grid of roughly 1.4 million elements, appropriate for annular and rotating-flow problems. The Power-Law viscosity model is configured in Fluent by setting the consistency index k, the flow behavior index n, and clamping the minimum and maximum viscosity bounds. The Eulerian multiphase model is set up with two implicit phases, including phase-specific densities, viscosities, and inlet volume fractions. A rotating wall boundary condition (100 rpm on the inner cylinder) is applied — essential for any Taylor–Couette-type analysis — and Coupled pressure–velocity coupling with PRESTO! pressure discretization is chosen for the rotating multiphase flow.

Analysis

Post-processing produces 2D and 3D contours of pressure, velocity, and volume fraction for both phases, revealing how the Power-Law fluid responds to the shear imposed by the rotating inner cylinder and how the denser secondary phase distributes through the annulus. From these fields you can study how the apparent viscosity varies with shear rate and how the two phases interact in the rotating annular flow. The same workflow underpins drilling mud analysis, polymer extrusion, blood flow in narrow vessels, paint coating, and food processing — anywhere viscosity isn't constant. By the end of this project, you'll be able to configure the Power-Law non-Newtonian viscosity model, set up an Eulerian two-phase flow with a rotating wall, and interpret the pressure, velocity, and volume-fraction fields that characterize non-Newtonian flow in a concentric-cylinder geometry.