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-nonconservative 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 multidimensional 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.