A Quasi-1D Three-Phase Deflagration Model with Detailed Finite-Rate Chemical Kinetics Mechanisms: Frozen Ozone (Revisited) and Plateau Burning Rates

Author(s):

Michael J. McQuaid

Abstract:

As a step toward establishing a physics-based modeling framework with the potential to reliably predict the pressure-dependent burning rates [𝑟(𝑃)] of catalyzed double-base propellants (DBPs), a quasi-1D three-phase model for simulating the deflagration of frozen (solid) ozone (𝑂_3,𝑠) was formulated and applied. To identify changes a catalyst would have to produce in the thermochemical kinetics of the system’s liquid phase (LP) to yield both “super-rate” and “plateau” burning-rate regions, the impacts of heuristic changes to the LP’s kinetics mechanism were calculated and assessed. A mechanism that produced an 𝑟(𝑃) plot with both super-rate and plateau regions was predicated on limiting chemical reactivity to a reversible one-step reaction for the decomposition of liquid ozone (𝑂_3,𝑙) to 𝑂_𝑙 and 𝑂_2,𝑙 and lowering the enthalpy of 𝑂_𝑙 from a best guess. In addition, the capacity of those predicates to produce a super-rate and plateau could be further enhanced by decreasing the liquid-to-gas volatilization rate in proportion to 𝑂_3,𝑙’s decomposition. The correspondence between this variation of the model and a chelation/complex-formation theory proposed to explain the super-rate burning of catalyzed-DBPs is apparent. Moreover, the model provides additional support for this theory by demonstrating that it can concomitantly produce a plateau region.