Multiphase CFD Simulations using OpenFOAM

This series of projects explores advanced multiphase flow modeling techniques using OpenFOAM, applied to industrially relevant scenarios involving gas-solid, liquid-solid, and free-surface dynamics. The simulations were conducted as part of the 6EMA08 Multiphase CFD course at TU/e.

Case studies include Euler-Euler modeling of fluidized beds, droplet impact on inclined surfaces, transient heat transfer from a sphere in stirred liquid, and spray drying dynamics with turbulence closure analysis. Each study was validated against experimental or analytical benchmarks, and sensitivity analyses were performed to assess spatial and temporal resolution effects.

Solid Temperature Profile – Validation of Numerical Methods

Heat Transfer in Solid–Liquid Systems

This project investigates the transient thermal interaction between a solid sphere and a well-stirred liquid in an insulated tank. Both explicit and implicit finite difference methods were implemented in Python to simulate the heat conduction in the sphere and energy exchange with the surrounding fluid.

The model was validated against an analytical solution derived from separation of variables. Error norms (L1, L2, L∞) confirmed high accuracy for the implicit method across multiple grid/time configurations. Results highlight the influence of the Fourier number and coupling strength on thermal response.

Solids Volume Fraction – Fluidized Bed Simulation

Gas-Solid Fluidization Modeling

This project compares two Euler-Euler modeling approaches in OpenFOAM: a standard model and one based on Kinetic Theory of Granular Flow (KTGF). Simulations were performed on a bubbling fluidized bed using the twoPhaseEulerFoam solver, with validation against experimental data.

Results were evaluated based on time-averaged void fraction, error metrics, and sensitivity to time step and mesh size. Despite KTGF's theoretical advantages, the standard model demonstrated better accuracy and computational efficiency under the given conditions.

Velocity Field – k-epsilon Turbulence Model in Spray Dryer

Spray Drying: Turbulence Model Comparison

Using OpenFOAM’s sprayFoam solver, this study modeled a scaled spray dryer to evaluate the impact of turbulence closures on atomized jet behavior. The k-epsilon and k-omega models were compared in terms of velocity decay, jet spreading, and near-wall accuracy, validated against experimental PIV data.

While both models provided reasonable predictions, the k-omega model consistently outperformed in capturing near-wall effects and core penetration, exhibiting lower numerical error and better alignment with experimental velocity profiles. Recommendations were made for future LES-based refinement.

Droplet Impact Simulation – Inclined Surface

Droplet Impact on Inclined Surfaces

This simulation investigates the spreading behavior of a water droplet impacting a 64.25° inclined hydrophilic surface using the Volume of Fluid (VOF) method in OpenFOAM. Two models were implemented to handle wetting dynamics: constant and dynamic contact angle boundary conditions.

The dynamic model more closely matched experimental observations, providing smoother spreading. The study highlights the importance of capturing contact line dynamics in impact simulations.