Abstract:
A model of turbulent-flame propagation in a boron-air mixture has been developed using the equation for the balance of the joint probability density function for temperature, boron-particle radius, and thickness of the oxide film on the boron-particle surface. The model includes the kinetic and diffusion mechanisms of component reactions, the particle-size distribution, and also the conductive and radiant heat transfer between the original cloud of boron particles and combustion products. We have studied the effect of the initial particle radius, mass particle concentration, and the turbulent-diffusion coefficient on the flame-propagation velocity and on the fluctuations of temperature, particle radius, and oxide-film thickness. The variation of the correlation coefficients for the above parameters during ignition and combustion is also shown. The calculations showed qualitative and quantitative differences in flame propagation for mono-and polydisperse systems. These differences are concerned with the flame-front velocity and macrostructure, heat and velocity states of the cloud of particles, and also its fluctuating and correlation characteristics.
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