Bontch-Osmolovskaia, Daria (2018) Improved Mixing Closure for Multiple Mapping Conditioning Turbulent Combustion Model. [USQ Project]
Abstract
This project contributes to the development of the hybrid binomial-Langevin Multiple Mapping Conditioning (bL‐MMC) closure modelling framework, used for simulating turbulent combustion in methane‐air open jets.
Currently, much of the world’s energy supply is dependent on burning fuels. Despite rapid developments in the renewable energy sector, our fuel supply must be improved by a simultaneous development of better combustion technologies. Turbulent combustion computational models allow engineers to simulate the behaviour of jet flames and their output pollutants, thus greatly reducing the need for physical tests. This significantly saves on the costs of building and testing expensive equipment.
One of the computational methods – the Reynolds‐Averaged Navier Stokes (RANS) transport equations for turbulent combustion – is effective but requires the use of complex mathematical closure models. One of such models is known as the ‘binomial‐Langevin Multiple Mapping Conditioning model’ (bl‐MMC), and this is the model used in this project.
The binomial‐Langevin equation simulates the amount of mixing of the fuel and air in the turbulent combustive field. This data is used in the Conditional Moment Closure (CMC) equation to calculate the chemical source input, conditioned by mixture fraction, and turbulent scalar dissipation and molecular diffusion. The resulting values are used to close the Probability Density Function (PDF) equation, which, in turn, closes certain unclosed terms within the RANS transport equations.
The RANS equations are then resolved to simulate the behaviour of a flame jet, including its turbulence, velocity of the flame front, molecular diffusion, chemical reactions and pollutant output. Finally, these data values can be used to assess the efficiency of the combustion process and its pollutant output.
The foundations of the model were originally encoded into Fortran in the mid‐1990s. The computational code has been continually developed and added to by multiple researchers over the years. The mathematical bL‐MMC model was developed in the 21st century by Dr. Andrew Wandel (the student’s supervisor) and encoded into Fortran.
This project contributes to the further development of the model and code, by introducing updated mixing equations and parameter values into the system, and by exploring the effect of the computational hardware and compilers on the performance of the code.
The results of the project were very positive, presenting new results and stronger validation against experimental data than has been previously obtained by Dr. Wandel. The project shows that this closure model is offering a positive option for continuing advanced turbulent combustion modelling using RANS framework and the bL‐MMC closure model.
The key recommendation for future work is to continue developing the model and code further, with an outlook to simulating diesel combustion –starting with pure diesels, and then lean and bio‐diesels.
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Statistics for this ePrint Item |
| Item Type: | USQ Project |
|---|---|
| Item Status: | Live Archive |
| Faculty/School / Institute/Centre: | Historic - Faculty of Health, Engineering and Sciences - School of Mechanical and Electrical Engineering (1 Jul 2013 - 31 Dec 2021) |
| Supervisors: | Wandel, Andrew |
| Qualification: | Bachelor of Engineering (Mechanical) |
| Date Deposited: | 02 Sep 2022 00:22 |
| Last Modified: | 27 Jun 2023 04:49 |
| Uncontrolled Keywords: | binomial-Langevin Multiple Mapping Conditioning (bL‐MMC); methane‐air open jets |
| URI: | https://sear.unisq.edu.au/id/eprint/40745 |
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