Comparison of solid phase closure models in Eulerian-Eulerian simulations of a circulating fluidized bed riser

Abstract

In this work, computational fluid dynamics with Eulerian-Eulerian modeling approach is used in the investigation of the effect of the solid phase closure models on the hydrodynamics of a circulating fluidized bed riser. The studied models are the kinetic theory of granular flow and the powder modulus model. Computational performance and model prediction accuracy are investigated by performing transient simulations for three different cases and for different mesh sizes. The modeling results are compared with measured vertical pressure profile, external circulation mass flow rates, and particle velocity and concentration profiles obtained from a laboratory scale circulating fluidized bed unit. Additionally the computational times are compared to estimate the computational performance and to investigate if a simpler set of closures is computationally more affordable. The results indicate that both closure models can give good predictions for some quantities, while lacking in other quantities. The results indicate that the closure models for the solid phase have a noticeable effect on the model predictions, such as the vertical pressure profile and external circulation rate of the particles.

Effects of heterogeneous flow on carbon conversion in gas-solid circulating fluidized beds

“…The hydrodynamical model frame was previously validated with measurements by Nikku et al [43], and a comparison of pressure profile results in an ambient temperature case without the fuel phase is presented in Figure 1C. A good agreement was achieved between the measurements and the hydrodynamic model, similarly with the same hydrodynamical modeling approach validation on other cases for example by Nikku et al [44]. The simulations were performed in parallel processing with 16 cores.…”

Effect of software implementation on the result of computational fluid dynamics simulation of circulating fluidized bed risers

“…More details on the probe measurements are found in Daikeler et al 41 The external circulation mass flow rate of particles was measured by briefly stopping fluidization in the loopseal and measuring accumulation of particles in the return leg. The same measured cases have been previously simulated by Stroh et al 42 with coarse‐grained Eulerian–Lagrangian approach and Nikku et al 43 with Eulerian–Eulerian approach.…”

Euler‐Lagrange‐Modell zur Simulation des Carbonate‐Looping‐Prozesses

“…Es wurden drei unterschiedliche Fluidisierungsgeschwindigkeiten (2,7 m s −1 , 2,3 m s −1 und 1,9 m s −1 ) untersucht, wobei Luft als Fluidisierungsmedium verwendet wurde. Ausführliche Versuchsergebnisse wurden bereits veröffentlicht , , außerdem wurden Euler‐Euler‐Simulationen durchgeführt, die ebenfalls veröffentlicht wurden .…”

“…Es wurden drei unterschiedliche Fluidisierungsgeschwindigkeiten (2,7 m s -1 , 2,3 m s -1 und 1,9 m s -1 ) untersucht, wobei Luft als Fluidisierungsmedium verwendet wurde. Ausführliche Versuchsergebnisse wurden bereits veröffentlicht[18,19], außerdem wurden Euler-Euler-Simulationen durchgeführt, die ebenfalls veröffentlicht wurden[20].Als Bettmaterial wurden Sandpartikel mit einer Dichte von 2647 kg m -3 verwendet. Eine Partikelgrößenverteilung wurde gemessen, wobei der Durchmesser der Sandpartikel im Bereich von 50-300 mm lag.…”