Reacting Flow: Diesel Fuel in a Gas Turbine Combustion Chamber

Diesel Fuel Combustion in a Gas Turbine Combustion Chamber — ANSYS Fluent CFD Simulation Training

This project simulates the combustion of diesel fuel inside the combustion chamber of a gas turbine system using ANSYS Fluent, with the full case analyzed through CFD post-processing.

The combustion chamber works as follows: air enters from the space surrounding the chamber, passes through a bladed diffuser duct where it becomes turbulent, and then enters the dedicated combustion space to mix more effectively with the fuel. The fuel, meanwhile, is injected into the chamber through a nozzle and mixes with the incoming air, allowing combustion to take place. The fuel used is diesel (C₁₆H₂₉), which reacts with the airflow.

The combustion reaction involves four species — diesel, hydrogen, oxygen, and carbon — so the Species Transport model is used to define the gaseous species, together with the volumetric reaction model to govern the reaction between them. Air enters the chamber at a velocity of 3 m/s and a temperature of 300 K, while diesel is sprayed into the chamber interior at 4 m/s and 300 K. The aim of the study is to investigate the mass fractions of the reactants and the combustion products.

The 3D geometry was created in Design Modeler and meshed in ANSYS Meshing using an unstructured grid, for a total of 3,488,057 cells.

Methodology

The Species Transport model is used to analyze the combustion process, and the energy equation is activated to compute the temperature changes throughout the domain.

Results

Once the solution is complete, 2D and 3D contours of pressure, temperature, velocity, and the mass fractions of diesel, oxygen, carbon dioxide, and water vapor are obtained.

The contours show that the fuel mixes well with the oxidizer and that combustion takes place, with its products clearly visible. The temperature is very high in parts of the combustion chamber, and the results show that the combustion flame is well formed.