The influence of chemical kinetics on detonation structure and propagation
Abstract/Contents
- Abstract
- Society's need to reduce anthropogenic CO2 emissions motivates engine efficiency research in the growing natural gas power generation and aviation sectors. One promising technology for these sectors is the detonation engine, which offers thermodynamic efficiency advantages over the conventional approaches to energy conversion. The detonation engine, however, suffers from difficulty stabilizing a detonation wave within engine geometries. This dissertation focuses on understanding, predicting, and extending the stable limits of detonation to alleviate this challenge. The effect of dopant concentrations of ozone (up to 3000 PPMv) added to detonable mixtures was evaluated through both experiments and numerical simulations. Ozone is predicted to act as an ignition promoter, reducing the time to ignition in detonation structure. Results show that ozone can reduce the size of detonation cellular structure proportionally to the associated reduction of the induction length (upwards of 70% in conditions evaluated in this dissertation). Experiments validate that ozone can then extend the detonation stable limits. This suggests that ozone can be used in engines to extend the operating space. Ozone is also a unique scientific tool to control the ignition delay time, and therefore cell size, in isolation from any other detonation property (i.e. CJ speed, post-shock and equilibrium states). The principles developed by studying ozonated detonation were used to study the differences in detonation properties between methane and natural gas (whose main component is methane). Experiments and simulations show that natural gas has a wider range of detonable conditions as compared to methane, indicating that, for an engine, it is a better fuel choice. This is true in spite of the composition variability inherent to natural gas, which is predicted to have a relatively minor impact on propagation behavior. These results further suggest that in safety studies, using methane, which is sometimes chosen as a surrogate for natural gas, is a highly-non-conservative choice. A theory was developed to predict detonation cellular stability. The theory is capable of predicting cell size without empirical correlations, and explains the difference in cell structure associated with different mixtures, including why ozone is so effective in reducing cell size. The theory is based on a negative feedback control on the size of blast kernels, which are the root of detonation cells. We developed the theory using 1D transient simulations, and tested it using 2D transient simulations. The cell stabilization theory is extended to produce a model which can predict multi-dimensional detonation cellular propagation with arbitrary boundary conditions and mixtures. The resulting model is computationally efficient, allowing rapid parametric studies of engineering-relevant geometries and thermodynamic conditions.
Description
| Type of resource | text |
|---|---|
| Form | electronic resource; remote; computer; online resource |
| Extent | 1 online resource. |
| Place | California |
| Place | [Stanford, California] |
| Publisher | [Stanford University] |
| Copyright date | 2021; ©2021 |
| Publication date | 2021; 2021 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Author | Crane, Jackson Thomas |
|---|---|
| Degree supervisor | Wang, Hai, 1962- |
| Thesis advisor | Wang, Hai, 1962- |
| Thesis advisor | Bowman, Craig T. (Craig Thomas), 1939- |
| Thesis advisor | Mani, Ali, (Professor of mechanical engineering) |
| Degree committee member | Bowman, Craig T. (Craig Thomas), 1939- |
| Degree committee member | Mani, Ali, (Professor of mechanical engineering) |
| Associated with | Stanford University, Department of Mechanical Engineering |
Subjects
| Genre | Theses |
|---|---|
| Genre | Text |
Bibliographic information
| Statement of responsibility | Jackson Crane. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis Ph.D. Stanford University 2021. |
| Location | https://purl.stanford.edu/nr577pc5759 |
Access conditions
- Copyright
- © 2021 by Jackson Thomas Crane
- License
- This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).
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