Wet Combustion Using DPM Combusting Particle CFD Simulation

Wet Combustion Using DPM Combusting Particle CFD Simulation

Welcome to this advanced episode of our “Combustion: All Levels” course. In this lesson, we delve into the intricate world of wet combustion simulation using the Discrete Phase Model (DPM) with combusting particles. This episode, which is the fourth chapter of our DPM training course, offers a unique exploration of complex combustion scenarios involving anthracite volatile in a combustion chamber.

Project Overview

Our simulation focuses on tracking fuel particles through the entire combustion process, from devolatilization to oxidation, resulting in the production of carbon dioxide and water vapor. This advanced model incorporates:

• A 2% liquid fraction in the fuel
• A 0.5-second injection duration
• Hot air introduction to the combustion chamber

This setup allows us to investigate the intricate dynamics of wet combustion, mimicking real-world scenarios in advanced combustion systems.

Simulation Methodology

Our simulation employs a sophisticated approach to model the complex processes involved in wet combustion.

Model Components

We utilize a combination of advanced modeling techniques:

• Species Transport Model: For accurate tracking of chemical species
• Discrete Phase Model (DPM): To simulate anthracite particles
• Combusting Particle Type: With a 2% liquid fraction

Particle Characteristics

The anthracite particles are modeled with specific properties:

• Initial temperature: 325K
• Non-spherical shape
• Rosin-Rammler diameter distribution

Geometry and Meshing

The simulation environment is carefully crafted:

• Geometry designed using ANSYS Design Modeler software
• Unstructured mesh grid generated with ANSYS Meshing software
• Conversion to polyhedron cells for reduced computational costs
• Final mesh count: 810,000 cells

Combustion Process and Reactions

The wet combustion process in our simulation follows a specific sequence:

1. Evaporation of the wet fraction of anthracite
2. Release of the volatile fraction
3. Oxidation of the volatile fraction

The key reaction modeled is:

1An-vol + 2.207 O2 → 0.1 CO2 + 4.408 H2O

This reaction leads to a significant temperature increase in the chamber, reaching up to 2400K.

Results and Analysis

Our simulation provides comprehensive insights into the wet combustion process:

• Temperature distribution throughout the combustion chamber
• Particle tracking from injection to complete combustion
• Species concentration profiles for O2, CO2, and H2O
• Energy release patterns during the combustion process

To enhance understanding, we’ve extracted animations that visually demonstrate these processes.

Learning Outcomes and Applications

By the end of this episode, you’ll have gained:

• Advanced understanding of wet combustion simulation techniques
• Insights into DPM and combusting particle modeling in CFD
• Skills to interpret complex CFD results for multi-phase combustion systems
• Knowledge of how particle properties affect combustion dynamics

These skills are directly applicable to:

• Designing efficient coal-fired power plants
• Optimizing biomass combustion systems
• Improving efficiency in industrial furnaces and boilers
• Advancing research in multi-phase combustion phenomena

Join us in this cutting-edge exploration of wet combustion simulation using DPM and combusting particles in ANSYS Fluent. Elevate your CFD expertise to new heights in advanced combustion modeling and gain valuable insights into complex industrial processes!