An anisotropic Reynolds mass flux model for the simulation of chemical reaction in gas-particle CFB risers. (2nd October 2015)

• Record Type: Journal Article
• Authors: Li, Wenbin; Yu, Kuotsung; Yuan, Xigang; Zhu, Jesse; Liu, Botan; Shao, Yuanyuan
• Is Part Of: Chemical engineering science. Volume 135(2015)
• Page Start: 117
• Page End: 127
• Publication Date: 2015-10-02
• Subjects: Circulating fluidized bed riser -- Mathematical model -- Computational fluid dynamics -- Two-fluid model -- Drag coefficient -- Anisotropic turbulent mass diffusion; Chemical engineering -- Periodicals; Génie chimique -- Périodiques; Chemical engineering; Periodicals; Electronic journals; 660
• DOI: 10.1016/j.ces.2015.05.047
• Languages: English
• ISSNs: 0009-2509

Abstract

Abstract: A model is proposed for numerical simulation of the multiphase flow coupled with chemical reaction in gas-particle circulating fluidized bed (CFB) risers. The proposed model is based on the newly developed computational mass transfer (CMT) methodology (Yu and Yuan, 2014 ) featuring the use of Reynolds mass flux equation to close the turbulent mass transfer equation, so that the anisotropic turbulent mass diffusion in CFB riser can be realized in the simulation. The proposed model consists of the turbulent mass transfer equation for the species with its Reynolds mass flux closure and the relevant formulations of computational fluid dynamics (CFD). With the proposed model, the species concentration and solid volume fraction as well as the velocity distributions along the CFB riser can be predicted. To validate the proposed model, simulation is carried out for the catalytic ozone decomposition in a gas-particle CFB riser. The simulated results are compared with the experimental data and satisfactory agreement is found in both axial/radial distributions of ozone concentration and solid volume fraction. Furthermore, the anisotropic turbulent mass diffusivities are also predicted and validated by the experimental data reported in literature. Highlights: An anisotropic model is proposed for simulating mass transfer process in CFB riser. Concentration distribution is obtained without relying on empirical Sc t number. Simulated results are in good agreement with experimental data in literatures. Anisotropic character of transport in the riser of CFB is revealed.