Improving Bed Movement Physics in Biomass Computational Fluid Dynamics Combustion Simulations

Abstract

A detailed description of the first functional new approach to simulate the bed physics in biomass boilers in a Eulerian mathematical framework is presented. In particular, the analysis of the context of the collapse due to gravitational forces, the design of an automated algorithm that is responsible for its simulation under ANSYS‐Fluent, the concrete implementation of this algorithm, and its test with experimental contrasted data are described. The proposed solution can replicate the angle of repose of different fuels in biomass combustion boilers by implementing a series of geometric mechanisms applied to the mesh. The selected approach mainly responds to a computational efficiency requirement; both memory management and execution speed are relevant.

Numerical Study on the Granular Flow and Heat Transfer of a Calcium Looping CO2 Capture System

“…Chaudhuri et al [35] employed DEM simulation to investigate the internal thermal temperature distribution of particles in a drum. Recently, the CM has also been widely applied in investigating granular flow behavior [36,37]. The gas phase is heated as a dispersed phase.…”

CFD Simulation of an Internally Cooled Biomass Fixed-Bed Combustion Plant

“…Apart from the shrinkage and compaction, the model also includes physics algorithms to simulate the effect of gravity on the solid fuel bed, which, being a granular material, will have a tendency to form piles [31,38]. In addition, the model has different fuel feeding methods, to simulate the feeding mechanisms of different combustion systems.…”

“…To discretize the domain, a polyhedral mesh is chosen, in order to reduce the number of elements needed, compared with a tetrahedral mesh. In addition, this type of mesh has already been used in biomass combustion simulations using the EBiTCoM model and has shown a better response in the bed physics algorithms, compared with other morphologies [26,31,38]. The domain includes the interior of the combustion plant, the solid walls, and the water-cooling circuits.…”

“…Eulerian models have been successfully used to simulate systems under different air/oxy-fuel conditions [28] and on different scales, from small experimental plants [27], to medium- [25] and large-scale systems [26,29]. Although these models do not treat the fuel bed as individual particles, physics algorithms can be implemented to simulate the movements and compaction of the solid fuel inside the systems [30,31]. In this work, the Eulerian biomass thermal conversion model (EBiTCoM), developed by the Energy Technology Group (GTE) of the University of Vigo, will be used.…”

Effect of Turbulence of the Freeboard on Fluidized‐Bed Biomass Combustion

“…Generally, there are two approaches for modeling a multiphase flow, namely Eulerian‐Eulerian and Eulerian‐Lagrangian. The Eulerian‐Eulerian approach, which treats all phases as continuum, has dominated the fluidized‐bed modeling due to relatively low computational cost 12. However, it can only predict the macroscopic characteristics of the particle cloud such as minimum fluidization velocity, pressure drop, bed height, and elutriation.…”