Numerical Modeling of Shockwave Initiated Combustion of a Hydrogen-Oxygen Mixture Within a Shock Tube

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Bibliographic Details
Title: Numerical Modeling of Shockwave Initiated Combustion of a Hydrogen-Oxygen Mixture Within a Shock Tube
Authors: Forehand, Reed
Committee Members: Kinzel, Michael
Summary: Shock tubes are as close to an ideal reactor as most modern experiments can attain to examine chemical kinetics. As reaction temperatures drop, homogeneous combustion within a shock tube begins to exhibit inhomogeneous modes, which in a typical Hydrogen-Oxygen system are ex- pressed as deflagration to detonation transition. Experimental results of such a system in the Uni- versity of Central Florida's low-pressure shock tube have been collected through end and side-wall imaging to analyze flame structure and chemical kinetics. The purpose of this work is to con- duct a baselining of these results using both chemical and computational fluid dynamics modeling. The model will use the Siemens STAR-CCM+ computational fluid dynamics software in order to accurately simulate the system. A seven-step reaction mechanism will be used to accurately capture initialization, propagation, and termination of the combustion within an implicit unsteady, three-dimensional, direct eddy simulation solution on a well-conditioned mesh. The end goal of this study is to create a lightweight model of hydrogen-oxygen combustion with a shock tube for baselining purposes. Both a two- and three- dimensional model were applied in this effort. The simulation results indicate good conditioning and agreement with the experimental results, although some combustion phenomena are not captured as well as a higher fidelity, significantly more computationally expensive model would.
URL: https://stars.library.ucf.edu/etd2020/678
Database: OpenDissertations
Description
Abstract:Shock tubes are as close to an ideal reactor as most modern experiments can attain to examine chemical kinetics. As reaction temperatures drop, homogeneous combustion within a shock tube begins to exhibit inhomogeneous modes, which in a typical Hydrogen-Oxygen system are ex- pressed as deflagration to detonation transition. Experimental results of such a system in the Uni- versity of Central Florida's low-pressure shock tube have been collected through end and side-wall imaging to analyze flame structure and chemical kinetics. The purpose of this work is to con- duct a baselining of these results using both chemical and computational fluid dynamics modeling. The model will use the Siemens STAR-CCM+ computational fluid dynamics software in order to accurately simulate the system. A seven-step reaction mechanism will be used to accurately capture initialization, propagation, and termination of the combustion within an implicit unsteady, three-dimensional, direct eddy simulation solution on a well-conditioned mesh. The end goal of this study is to create a lightweight model of hydrogen-oxygen combustion with a shock tube for baselining purposes. Both a two- and three- dimensional model were applied in this effort. The simulation results indicate good conditioning and agreement with the experimental results, although some combustion phenomena are not captured as well as a higher fidelity, significantly more computationally expensive model would.