Simulation of Partially Premixed Combustion in a Co-axial Combustor
The purpose of this tutorial is to provide guidelines and recommendations for setting up and solving a reacting ﬂow using the partially premixed combustion model. This tutorial demonstrates how to do the following:
- Create a probability density function (PDF) ﬁle for a combustion system.
- Deﬁne ANSYS Fluent inputs for PDF chemistry modeling.
- Use the partially premixed Zimont turbulent ﬂame speed model to simulate the combustion system.
- Solve the case with appropriate solver settings.
- Postprocess the results to investigate the premixed and non-premixed properties.
The coaxial combustor considered is shown in the following ﬁgure. A swirler at the center of the combustor introduces the lean methane/air mixture (equivalence ratio=0.8) of temperature 300 K with an axial velocity of 50 m/s and swirl velocity of 30 m/s. Pure air at an axial velocity of 10 m/s and temperature 650 K is introduced from the outer tube to stabilize the ﬂame. The major species involved in the combustion process are CH4, O2, CO2, CO, H2O, and N2.
The key to the premixed combustion model is the prediction of the turbulent ﬂame speed, the turbulent ﬂame speed normal to the mean surface of the ﬂame. The turbulent ﬂame speed is inﬂuenced by the following:
- Laminar ﬂame speed, which is, in turn, determined by the fuel concentration, temperature, and molecular diﬀusion properties, as well as the detailed chemical kinetics
- Flame front wrinkling and stretching by large eddies, and ﬂame thickening by small eddies
Numerous turbulent ﬂame speed models have been derived. You will be using the Zimont Turbulent Flame Speed Model (for details refer to section 9.4.1 of the ANSYS Fluent 14.5 Theory Guide).
The partially premixed model in ANSYS Fluent can be used to simulate a combustion system, where the combustion process is neither purely premixed nor purely non-premixed. Both premixed and non-premixed properties can be investigated using the postprocessing results.
This tutorial demonstrated the application of the partially premixed model, based on both non-premixed (mixture-fraction based) and premixed (mean progress variable based) models.
Mr CFD Company services
Due to the wide range of mechanical science and the different fields of work as well as the abundance of projects, this company offers to view all the products presented in this section. In the absence of any desired project or project close to your request, you can search our portfolios in order to find your eligible project, after all, if you didn’t find any ideal project you can order your project from the services pages on the header of this website. Your order will be reviewed by our experts in the shortest possible time, and if we need more information about the proposed project, we will be in touch with you. After completing the required information to examine the proposed project, and confirming your request, the time, conditions and costs will be sent to you during the contract. This process will take place as soon as possible. If you have any questions, you can contact our online support section (the fixed blue tab below the page). If it is offline, don’t worry, you can post your message, and it will be answered as soon as possible.