A Spouted Bed CFD simulation is a computer model of a special type of reactor used in many industries. It is a key tool in CFD for Particle Technology. Unlike normal beds, a spouted bed uses a strong, central jet of fluid to mix solid particles very well. This is a type of Granular Flow CFD. This helps processes like drying grain, coating tablets, and Chemical Reactor Simulation. A Spouted Bed Fluent analysis shows us the three main zones inside: the fast central “spout,” the “fountain” at the top, and the slow-moving “annulus” on the sides. This study uses the Two Fluid Method (TFM) to accurately model this complex Multiphase Flow Simulation, and it is validated against the work of Moliner et al. [1,2].

• Reference [1]: Moliner, Cristina, et al. “CFD simulation of a spouted bed: Comparison between the Discrete Element Method (DEM) and the Two Fluid Model (TFM).” Chemical Engineering Journal377 (2019): 120466.
• [2]: Moliner, Cristina, et al. “Sensitivity analysis and validation of a Two Fluid Method (TFM) model for a spouted bed.” Chemical Engineering Science207 (2019): 39-53.

Figure 1: A schematic showing the three distinct flow regimes (spout, fountain, annulus) in a Spouted Bed Fluent simulation. [1]

Simulation Process: Fluent Setup, Eulerian-Eulerian TFM for Granular Flow Simulation

To perform this Spouted Bed CFD Simulation Using Two Fluid Method (TFM) Fluent study, we first created a simplified 3D geometry of the experimental setup using Design Modeler. We then discretized this domain by creating a structured grid made of 7500 high-quality cells to ensure an accurate solution. In the ANSYS Fluent solver, we used the Eulerian multiphase model to set up the physics. This powerful model implements the Two Fluid Method (TFM), which is perfect for this problem. It treats both the gas and the solid particles as two separate but interacting fluids. We defined one phase as the gas and the other as a granular solid phase. To make the simulation realistic, we set the properties for the solid particles and defined the crucial interaction forces between the gas and the particles, such as the drag model and lift forces. Because the spouting motion develops and changes over time, we ran the simulation using the unsteady (transient) solver.

Figure 2: The simplified 3D geometry and the structured mesh with 7500 cells used for the Eulerian-Eulerian Model Fluent analysis. [1]

Post-processing: CFD Analysis, Deconstructing the Spouted Bed Hydrodynamics

The particle velocity contour, taken at 5.6279 seconds, is a diagnostic snapshot of the reactor’s internal mechanics. From an engineering standpoint, this result is a clear success because it perfectly captures the three distinct regions that define a working spouted bed. The central spout acts as the system’s engine. It is a powerful upward jet with the highest particle speeds, reaching up to 2.61 m/s. This high-energy core is responsible for lifting the solid particles from the bottom of the bed. At the top, the spout’s energy creates the fountain, a plume of particles with speeds between 1.23 and 1.84 m/s. This zone is where the particles are thrown outwards to the top surface, ready to fall back down.

Figure 3: A contour of solid particle velocity from the Spouted Bed CFD simulation at 5.6279 seconds, clearly showing the spout, fountain, and annulus zones.

This brings us to the most important part of the cycle: the annulus. This region, which makes up most of the bed’s volume, shows particles moving very slowly downwards, with speeds near 0 to 0.46 m/s. The slow, downward drift in the annulus is the critical return path that feeds particles back to the bottom of the spout. The contour also reveals two symmetrical light-blue zones near the base, with speeds of 0.77 to 0.92 m/s. An engineer sees these not just as patterns, but as the entrainment zones—the precise locations where particles from the annulus are sucked back into the powerful spout. The most important achievement of this simulation is its ability to capture the entire dynamic, self-sustaining cycle of particle motion—from the high-speed spout, through the fountain, down the slow annulus, and back into the spout—providing clear proof that the Two-Fluid Method can successfully predict the complex hydrodynamics of a spouted bed.