Diffusion and hydrodynamic instabilities in gaseous detonations

摘要: Abstract To clarify the role played by diffusion in detonation structure, two-dimensional numerical simulations are performed solving Navier–Stokes equations and considering single step Arrhenius kinetic as reaction model. The effect of on generation vortices produced hydrodynamic instabilities (Richtmyer–Meshkov (RM) Kelvin Helmholtz (KH) instabilities) is investigated. Mixtures with both low high activation energies, characterized their regular irregular structures, considered. computations resolutions ranging from 25 to 10 3 cells per half length ZND structure. Resolution studies solution for detonations moderate energy mixtures shows that capture a proper be at least qualitative agreement experimental observations, resolution more 300 required. However, gives reasonable physical structure detonation. Results provided very reveal major occurs shear layers unburned pockets boundaries. Diffusion suppresses small-scale KH decreases turbulent mixing rate burned partly gases layers. behind shock front, where less concentration exist, heat mass neighboring hot regions material unreacted increases burning un-reacted pockets. Comparison obtained Euler that, strength front higher than solution. Due absence main detonations, results similar even simulations.