ThermoAcoustics Analysis in Combustion Chamber, CFD Simulation Tutorial

Description

This project, Non-Premixed Combustion & Acoustics, investigates a Thermoacoustic phenomenon inside a chamber using CFD simulation in ANSYS Fluent software. In thermoacoustic systems, heat is used to generate sound waves, which can then be used to perform various tasks like pumping heat or producing electricity. The process involves no moving parts, making it a reliable and low-maintenance technology.

The methane and oxygen enter the domain from different inlet boundary conditions with a mass flow rate of 0.001kg/s and 0.025 kg/s, respectively, and after mixing, the combustion occurs. In this case, the Acoustic Power Level (db) and Surface Acoustic Power Level (db) (Acoustic Power Level measures the total sound power, while Surface Acoustic Power Level measures the sound power per unit area.) are extracted using the steady-state acoustic model available in the software.

The geometry of the solution is designed in SpaceClaim software, and the elements of the meshing process are generated in ANSYS Meshing software.

Methodology of ThermoAcoustics Analysis in Combustion Chamber, CFD Simulation Tutorial

In this simulation, the Non-Adiabatic, Non-Premixed Combustion model models the combustion. The Non-Adiabatic, Non-Premixed Combustion model considers the heat loss that can occur during combustion. This means that some of the heat generated by the combustion is lost to the surroundings. This model is more realistic and is used in practical calculations where heat loss cannot be ignored.

Also, the acoustic is modeled via the Broadband Noise Source model. This model predicts the broadband noise of turbulent flows in a computational fluid dynamics (CFD) simulation.

Conclusion

The figures extracted from ANSYS Fluent software show the different contours of various parameters. The mass fraction of the material indicates its entry into the domain from the center of the inlet plate. Additionally, air with a mass fraction of 0.23 oxygen and the rest of the nitrogen enters the zone surrounding the fuel inlet. Also, the mass fraction contours of and, which are the products of the reaction, are visible.

At last, the contours of the Surface Acoustic Power Level on the chamber walls and Acoustic Power Level in the plane defined in the center of the chamber are apparent. The maximum amount for the Surface Acoustic Power Level is 73.56 db. This Surface Acoustic Power Level value is lower but is 62.93.