Microcombustor simulation with finite-rate chemistry

Baines, Joshua (2012). Microcombustor simulation with finite-rate chemistry B.Sc Thesis, School of Engineering, The University of Queensland.

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Author Baines, Joshua
Thesis Title Microcombustor simulation with finite-rate chemistry
School, Centre or Institute School of Engineering
Institution The University of Queensland
Publication date 2012
Thesis type B.Sc Thesis
Supervisor Peter Jacobs
Total pages 30
Language eng
Subjects 09 Engineering
Formatted abstract
This thesis investigates the CFD simulation of microcombustion devices. Microcombustors are combustors with typical dimensions on the millimetre scale. The aim of this thesis was to improve UQ's ability to perform CFD simulation of microcombustors using the Eilmer3 software.

Several failure modes must be mitigated in order to successfully operate a microcombustor. CFD simulation allows the study of the performance of various designs without requiring experimental investigation. Previous work has been undertaken at UQ to establish CFD models of microcombustors. The previous work used a constant volumetric heat addition model to simulate combustion. While this method allows for study of flow patterns within the combustor, it cannot definitively predict whether combustion will be stable for a given situation.

A finite rate chemistry model was applied to provide a more accurate simulation, and also allow for analysis of failure modes. The model used was gri-mech 3.0, a model which captures a large number of intermediate reactions and species. This model was chosen as it would provide the greatest accuracy. Due to the number of reactions and species considered in the gri-mech model, the computation time was significantly increased. Future use of this model would require greater computing resources in order to complete simulations in reasonable time frames.

The previous studies of microcombustor performance used a nozzle at the combustor exit to control flow rates through the combustor. It was proposed to replace the nozzle with a section of porous material at the entrance to the combustor. The eilmer3 software did not have the capability to model flow through porous material. A function was created to model flow through porous media, the function was based upon a modified form of Darcy's law. The porous material function showed good results, and proved effective at controlling the flow rate from a pressurised reservoir.
Keyword Microcombustion
power source
energy extraction

Document type: Thesis
Collection: UQ Theses (non-RHD) - UQ staff and students only
Citation counts: Google Scholar Search Google Scholar
Created: Thu, 25 Sep 2014, 14:40:00 EST by Jessica Minshull on behalf of Scholarly Communication and Digitisation Service