A combustion model of boron particles for detailed Computational Fluid Dynamics (CFD) based simulations of ducted rocket combustion chambers is studied. It is aimed to construct a model for combustion of boron containing gas mixtures ejected from a solid propellant gas generator. This model includes all main physical processes required to define an accurate particle combustion simulation. The reaction rate modeling in similar, previous studies are improved for ramjet combustion chambers and this model provides better predictions for all particle sizes. The reactions in the ignition stage are reformulated as competing reactions for consumption of (BO)(n) polymers. Large discrepancies between the experimental and calculated ignition times for the 3 mu m diameter particles in similar studies are eliminated. The developed model is added to a commercial CFD solver and can be used along with gas phase detailed turbulent combustion simulations of ducted rocket combustion chambers. Our simulation approach has provided us an effective tool, which allows us to forecast the effects of the changes on the performance and efficiency. This detailed combustion model is validated with existing experimental results available in open literature. The model is also compared with the results of similar previous studies. (C) 2017 The Combustion Institute. Published by Elsevier Inc. All rights reserved.