Development of a filtered reaction rate model for reactive gas–solid flows based on fine‐grid simulations

Abstract

AbstractThe filtered reaction rate for the coarse‐grid simulations of reactive gas–solid flows can be obtained via a correction to its microscopic reaction rate. The correction term is defined as the mesoscale effectiveness factor ηΔ, which is the ratio of the reaction rate obtained from the fine‐grid simulations to that obtained from the coarse‐grid simulations. The considered reaction is an isothermal, solid‐catalyzed surface reaction with a power law reaction rate model. The simulation results show that the mean ηΔ is almost invariant with the reaction orders at the same Damköhler number. A closure correlation for the mean ηΔ is formulated. However, the standard deviation of ηΔ is found to be quite large. A presumed probability density function model is proposed to capture the fluctuating properties of ηΔ. The predictability of the closure correlations are evaluated via performing the filtered two fluid model simulations in circulating fluidized beds of ozone decomposition.