Electrolysis Stack CFD Simulation

Electrolysis Stack CFD Simulation in ANSYS Fluent: Advanced Modeling Guide

Welcome to the fifth chapter of our Electrolysis Training Course, focusing on Electrolysis Stack simulation using ANSYS Fluent. This advanced module explores the complexities of modeling multiple electrolyzer units, providing cutting-edge CFD simulation techniques for large-scale hydrogen production systems.

Understanding Electrolysis Stacks

Before diving into the simulation process, let’s establish a clear understanding of electrolysis stacks:

Electrolysis vs. Fuel Cells

• Fuel Cells: Convert chemical energy to electrical energy
• Electrolysis: Reverse process, consuming electricity to produce hydrogen fuel

Electrolyzer Stack Components

Key components in each unit include:

• Anode and cathode
• Electrolyte membrane layer
• Current collectors
• Gas diffusion layers (porous electrodes)
• Catalyst layers
• Flow channels

An electrolysis stack combines multiple electrolyzer units for increased hydrogen production capacity.

Electrolysis Stack Simulation Methodology

Our simulation approach utilizes ANSYS Fluent’s advanced CFD capabilities:

Geometry and Meshing

• 3D model created using Design Modeler software
• Structured meshing with ANSYS Meshing software
• 279,868 cells generated for precise simulation

Simulation Setup in ANSYS Fluent

• Utilization of the fuel cell and electrolysis model (add-on module)
• Implementation of the electrolysis sub-model
• Configuration of electrolyzer layers
• Use of stack management option for multiple units

Key Simulation Models and Parameters

Species Transport Model

• Modeling of H2, O2, and H2O for electrochemical reactions

Electrolyzer Layer Configuration

Detailed setup of:

• Current collectors
• Gas diffusion layers
• Catalyst layers
• Gas flow channels

Simulation Results and Analysis

Our comprehensive simulation yields valuable insights:

Contour Analysis

Examination of contours for:

• Electric potential
• Protonic potential
• Current flux density magnitude
• Transfer current
• Mass fractions of H2, O2, and H2O

Electrochemical Behavior Insights

• Water vapor entry from the anode side
• Hydrogen production on the anode side
• Oxygen production on the cathode side

These results align with the expected functional mechanism of the electrolysis system, confirming the accuracy of our stack simulation.

Advanced Analysis Features

User-Defined Scalars (UDS)

• Electric potential (scalar 0)
• Protonic potential (scalar 1)

These scalars provide insights into electron and proton behavior within electrolyzer layers.

User-Defined Memories (UDM)

• Current flux density magnitude (UDM 3)
• Transfer current (UDM 13)

These UDMs confirm the presence and distribution of electric current in the electrolyzer stack.

Why This Electrolysis Stack Simulation is Crucial

This simulation module offers:

• Practical application of advanced CFD techniques for large-scale electrolysis systems
• Deep understanding of stack behavior and interactions between units
• Insights into optimizing performance and efficiency of electrolysis stacks

Target Audience

This module is ideal for:

• CFD specialists focusing on industrial-scale electrochemical processes
• Researchers in renewable energy and large-scale hydrogen production
• Engineers developing and optimizing electrolysis stack systems

Learning Outcomes

Upon completing this module, you will be able to:

• Set up and run complex electrolysis stack simulations in ANSYS Fluent
• Interpret advanced CFD results related to multi-unit electrochemical processes
• Apply sophisticated modeling techniques to optimize electrolysis stack designs

Elevate your electrolysis simulation skills to the industrial scale with this comprehensive guide to electrolysis stack modeling in ANSYS Fluent. Master the intricacies of large-scale hydrogen production and contribute to the advancement of sustainable energy technologies!