Combustion Chamber: Radiation Heat Transfer

Radiation Heat Transfer in Combustion Chamber, ANSYS Fluent Training

Description

This project investigates the steady combustion of methane and air within a simple extended cubical combustion chamber using ANSYS Fluent, with particular attention to radiation heat transfer — a critical consideration given the extremely high temperatures involved in combustion chambers. The 3D geometry was designed in Design Modeler and meshed in ANSYS Meshing, totaling 384,112 elements.

Methodology

The simulation captures a mixture static temperature reaching a maximum of 3500 K within the chamber. Methane and air enter the domain through separate inlets — methane through a single inlet, while airflow enters through two inlets to promote a more uniform fuel-air mixture. Air and fuel enter at mass flow rates of 0.00468 kg/s and 0.000205 kg/s, respectively.

The chemical reaction between methane and air produces CO₂ and H₂O; since the combustion is air-rich, oxygen and nitrogen remain unconsumed at the end of the reaction. The Species Transport model was activated to simulate combustion, with volumetric reactions enabled.

Given the high temperatures generated within the chamber, radiation heat transfer required explicit modeling, so the Discrete Ordinates (DO) model was also enabled. Turbulence was resolved using the RNG k-epsilon model, chosen for its ability to more accurately capture intense heat flux generation within the domain compared to other k-epsilon variants.

Conclusion

Results include 2D contours of temperature, velocity, species mass fraction, streamlines, and velocity vectors throughout the combustion chamber, with an outlet mixture mass flow rate of 0.004885042 kg/s. The primary combustion process occurs within the chamber itself, clearly visible in the temperature and reaction heat contours, which show the maximum temperature gradient and peak reaction heat concentrated in this region. The combustion process is similarly evident in the species mass fraction contours — the CO₂ mass fraction, for instance, shows a sharp increase corresponding directly to the combustion reaction taking place.