Partially Premixed Combustion Composition PDF Transport CFD Simulation

Partially Premixed Combustion Composition PDF Transport

Welcome to the ninth episode of our comprehensive “Combustion: All Levels” course. In this advanced lesson, we delve into the intricate world of partially premixed combustion and Composition PDF Transport using ANSYS Fluent software. This episode offers a unique exploration of complex combustion scenarios, combining multiple inlet conditions and sophisticated modeling techniques.

Simulation Overview

Our simulation focuses on a two-dimensional combustion chamber model with three distinct inlet boundaries:

• Pure air inlet
• Fuel-air mixture inlet
• Pilot inlet (combusted flow for activation energy)

This setup allows us to investigate the intricate dynamics of partially premixed combustion in a controlled environment, mimicking advanced combustion systems found in industry.

Model Geometry and Meshing

The foundation of our simulation is a meticulously crafted model:

• Geometry designed using Design Modeler software for precision
• Meshing performed with ANSYS Meshing software
• Structured mesh type for optimal accuracy
• 2,352 elements ensuring detailed results while maintaining computational efficiency

Simulation Methodology

Our simulation process is divided into three distinct phases, each building upon the previous to achieve a comprehensive and accurate result.

Phase 1: Partially Premixed Combustion Model

In this initial stage, we:

• Utilize a Partially Premixed Combustion model
• Implement Non-Adiabatic energy treatment
• Apply a Chemical Equilibrium model for combustion processes
• Generate a PDF table for efficient data storage and retrieval
• Employ the Zimont model for turbulent flame speed calculations

Phase 2: Composition PDF Transport

Building on the initial solution, we:

• Enable Composition PDF Transport for more detailed modeling
• Incorporate a Chemkin Mechanism for comprehensive reaction modeling
• Implement ISAT (In Situ Adaptive Tabulation) along with Chemistry Agglomeration
• Balance simulation speed with acceptable error margins

Phase 3: Final Accurate Solution

In the final stage, we refine our results by:

• Disabling Chemistry Agglomeration for increased accuracy
• Continuing to utilize the ISAT table populated in Phase 2
• Achieving a high-fidelity solution that captures complex combustion dynamics

Additional Settings

Throughout all phases, we maintain:

• Enabled Energy equation for accurate temperature change calculations
• Standard k-epsilon model for turbulence modeling

Results and Analysis

Upon completion of the simulation, we analyze a range of outputs including:

• Temperature distribution contours
• Velocity profiles throughout the chamber
• Mass fractions of various species
• Streamlines revealing flow patterns and mixing zones

These results provide invaluable insights into:

• The progression of combustion in a partially premixed environment
• Temperature evolution across different chamber regions
• Species formation and consumption patterns
• The impact of the pilot inlet on overall combustion dynamics

Learning Outcomes and Applications

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

• Advanced understanding of partially premixed combustion simulation techniques
• Insights into Composition PDF Transport modeling in CFD
• Skills to interpret complex CFD results for multi-inlet combustion systems
• Knowledge of balancing computational efficiency with simulation accuracy

These skills are directly applicable to:

• Designing advanced gas turbine combustors
• Optimizing multi-fuel combustion systems
• Improving efficiency in industrial furnaces and boilers
• Advancing research in complex combustion phenomena

Join us in this cutting-edge exploration of partially premixed combustion and Composition PDF Transport simulation using ANSYS Fluent, and elevate your CFD expertise to new heights in advanced combustion modeling!