Validation of the similar particle assembly (SPA) model for the fluidization of Geldart's group A and D particles

Abstract

in Wiley Online Library (wileyonlinelibrary.com).The similar particle assembly (SPA) model proposed for large-scale discrete element method simulation was validated. The SPA model describes the scaling law for the motion of particles in an assembly, which is derived from the equation of motion of a particle. In the SPA model, particles with similar physical or chemical properties are represented by a single particle, which is called the representative particle. The local assembly of particles in the original bed is supposed to be maintained in the bed with the representative particles. The SPA model was validated by numerical simulations of a 2D fluidized bed of noncohesive and cohesive particles. Using the SPA model, the flow behavior of the representative particles of a certain magnification can be made similar to that of the original particles with significantly less computational load. A good approximation of bubble size distribution between the SPA bed and the original bed was obtained.

Numerical investigations of a pseudo-2D spout fluidized bed with draft plates using a scaled discrete particle model

“…This leads to dramatic reduction in the total particles retaining similar bed characteristics. In a similar way, Mokhtar et al (2012) proposed a similar particle assembly (SPA) model by considering Geldart A and D particles and reported good agreement with experimental findings.…”

Coarse-Grain DEM Modelling in Fluidized Bed Simulation: A Review

“…Kuwagi et al [19] introduced the Similar Particle Assembly (SPA) concept, according to which the solids mass and volume were kept constant upon coarse graining, and volume fraction and flow similarity of the particles and the grains was assumed, i.e., ε g = ε p and v g = v p (v p = average particle velocity), respectively. They later used the SPA model to model thermoset particles with a large coarse graining factor, f = 200 (corresponding to 8000 grains for 64 billion particles) [14] and later validated it for bubble size distribution in a 2D gas-fluidized bed of Geldart's group A and D particles [59]. Washino et al [60] also introduced scaling rules considerations by dimensionless groups in DEM simulations of fluid beds, showing attractive computational scaling properties (log CPUtime = −2.55•log f ).…”

“…In Mokhtar (2012) [59], the Similar Particle Assembly model [20] is integrated with the cohesive liquid bridge force, which is not scaled. Grains have diameter f times that of the particle, with equal density and assuming same velocities.…”

Development of Simpler Coarse-Grain Model for Analyzing Behavior of Particles in Fluid Flow

“…In the coarse-grain models, the powder behavior is generally represented by coarse-grained particles (CG particles) that is equivalent to the original particles in something physical despite having a larger diameter. There are representative models that use the concept of the coarse-grain models already, such as the similarity model by Washino et al [14], the imaginary sphere model by Sakano et al [15], and the similar particle assembly model by Kuwagi et al [16,17], to represent the particle Processes 2021, 9, 1098 2 of 13 behavior in fluidized beds. For instance, in the case of the imaginary sphere model, an imaginary sphere is the CG particle and is defined as a cluster of original particles.…”