Analysis of gas phase detonation wave structure at elevated initial pressures

The characteristic "structure" of gaseous detonation waves, defined as the spatial variation of the pressure, temperature, density, and velocity within the detonation wave, was examined theoretically at elevated initial pressures. Gaseous detonations at elevated initial pressures lie in a regime that bridges the gap in knowledge between ideal gas and condensed-phase detonations. The approach taken in this thesis is to extend the Zel'dovich-von Neumann-Doering (ZND) theory of gas-phase detonation to use real-gas equations of state. This hybrid approach combines the theoretical tools used for analysis of gas- and condensed-phase detonations.; Chemkin Real Gas, a computer program capable of calculating real-gas thermodynamic properties and chemical kinetic reaction rates, was expanded to utilize the ideal gas, van der Waals, Redlich-Kwong, Soave, and Peng-Robinson equations of state to describe the P-V-T behavior of the gaseous mixtures used in this investigation. The Chapman-Jouguet (CJ) theory of detonation was used to examine the variation of the detonation state properties as a function of the initial pressure, temperature, and composition. The CJ numerical calculations are shown to be relatively insensitive to estimated equation of state dependent constants. The real-gas equations of state are shown to predict accurately the variation of the experimentally measured detonation velocities with initial pressure.; The mathematical model for the ZND detonation wave is presented in an equation of state independent form. The governing equations are integrated numerically for a hydrogen-oxygen system to determine the structure of the detonation wave. The ZND model was used to characterize the thermodynamic states and reaction zone length scales present in the detonation wave. The variation of the reaction zone length parameters was examined as a function of the initial pressure, temperature, and composition. The distance from the shock front to the maximum temperature derivative was shown to be a reproducible point of interest in the detonation wave structure and was used to estimate the lean detonation limit as a function of initial pressure. The numerical calculations exhibit sensitivity to equation of state dependent constants and pre-exponential rate coefficients in the elementary reaction mechanism.