A computational particle fluid dynamics （CPFD） numerical method to model gas-solid flows in a circulating fluidized bed （CFB） riser was used to assess the effects of particle size distribution （PSD） on solids di...A computational particle fluid dynamics （CPFD） numerical method to model gas-solid flows in a circulating fluidized bed （CFB） riser was used to assess the effects of particle size distribution （PSD） on solids distribution and flow. We investigated a binary PSD and a polydisperse PSD case. Our simulations were compared with measured solids concentrations and velocity profiles from experiments, as well as with a published Eulerian-Eulerian simulation. Overall flow patterns were similar for both simulation cases, as confirmed by experimental measurements. However, our fine-mesh CPFD simulations failed to predict a dense bottom region in the riser, as seen in other numerical studies. Above this bottom region, distri- butions of particle volume fraction and particle vertical velocity were consistent with our experiments, and the simulated average particle diameter decreased as a power function with riser height. Interactions between particles and wails also were successfully modeled, with accurate predictions for the lateral profiles of particle vertical velocity. It was easy to implement PSD into the CPFD numerical model, and it required fewer computational resources compared with other models, especially when particles with a polydisperse PSD were present in the heterogeneous flow.展开更多
基金provided by the National Program on Key Basic Research Project(973 Program) of China(No.2012CB214900)the financial support from Tekes,VTT Technical Research Centre of Finland,Etel-Savon Energia Oy,Fortum,Metso Power Oy and Numerola Oythe support from Saarijrven KaukolmpOy.
文摘A computational particle fluid dynamics （CPFD） numerical method to model gas-solid flows in a circulating fluidized bed （CFB） riser was used to assess the effects of particle size distribution （PSD） on solids distribution and flow. We investigated a binary PSD and a polydisperse PSD case. Our simulations were compared with measured solids concentrations and velocity profiles from experiments, as well as with a published Eulerian-Eulerian simulation. Overall flow patterns were similar for both simulation cases, as confirmed by experimental measurements. However, our fine-mesh CPFD simulations failed to predict a dense bottom region in the riser, as seen in other numerical studies. Above this bottom region, distri- butions of particle volume fraction and particle vertical velocity were consistent with our experiments, and the simulated average particle diameter decreased as a power function with riser height. Interactions between particles and wails also were successfully modeled, with accurate predictions for the lateral profiles of particle vertical velocity. It was easy to implement PSD into the CPFD numerical model, and it required fewer computational resources compared with other models, especially when particles with a polydisperse PSD were present in the heterogeneous flow.
