Filtered reaction rate model incorporating intraparticle diffusion for reactive gas–solid flows

Abstract This work pursues an integrated filtered reaction rate (FRR) model that incorporates intraparticle diffusion effectiveness factor ( η I ) into a framework combining reaction kinetics regime (KR) and external mass transfer regime (EMTR) via fine‐grid two‐fluid model (TFM) simulations. Simulation results indicate that the modified Damköhler number remains a reliable criterion for distinguishing between KR and EMTR. Within the KR, the FRR model that neglects η I overestimates the mesoscale effectiveness factor ( η Δ ) when η I < 0.5, though these effects become negligible at η I >0.5. This overestimation is attributed to the increase in the Damköhler number with decreasing η I , which subsequently results in a lower η Δ . Accordingly, an integrated FRR model incorporating η I is proposed. Coarse‐grid TFM simulations demonstrate that the FRR model without intraparticle diffusion yields only modest improvements, whereas the version integrated with intraparticle diffusion achieves substantially better agreement with the filtered fine‐grid TFM results.