Eulerian CFD Simulation of Geldart Group A Particle Agglomerates
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Solution Overview
Problem
Existing computer-based simulation models for gas-solid fluidized beds, particularly those using Eulerian-Eulerian frameworks, face limitations when modeling Geldart group A particles due to inaccuracies related to agglomerate formation and the reliance on arbitrary empirically-determined parameters, which restricts their applicability to specific operating conditions.
Innovation Solution
A method and system that discretize fluidized beds into Eulerian cells and simulate the behavior of gas-solid mixtures over discrete time steps, performing force-balance procedures to determine agglomerate diameters and update drag relationships, allowing for more accurate determination of gas and particle velocities, pressures, and solid fractions, while accounting for forces like van der Waals, collision, and gravitational forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If prior art CFD models use Eulerian-Eulerian frameworks to simulate gas-solid fluidized beds, then large scale fluidized beds can be modeled, but inaccuracies occur when modeling Geldart group A particles due to arbitrary empirically-determined parameters
Solution Approach 1:
The patent changes the fundamental parameters used in the simulation by replacing arbitrary empirically-determined parameters with physically-based parameters including agglomerate diameter, van der Waals forces, collision forces, and drag relationships. This allows the model to accurately represent Geldart group A particle behavior across different operating conditions without relying on empirical corrections.
Solution Approach 2:
The patent introduces an intermediary agglomerate structure that mediates between individual particles and the continuous phase. By modeling particles as agglomerates with specific diameters and force relationships, the simulation can capture cohesive effects and cluster formation behavior that were previously represented only by arbitrary empirical parameters.
2Reliability
If arbitrary empirically-determined parameters are used in fluidized bed models, then specific operating conditions can be matched, but the model becomes restricted to those specific conditions
Solution Approach 1:
The patent creates a universal simulation framework that can model different fluidized bed systems and operating conditions using the same physically-based equations. The model incorporates universal force relationships (van der Waals, collision, drag) and agglomerate dynamics that apply across various particle types and operating conditions, eliminating the need for system-specific empirical parameters.
3Measurement precision
If cohesive forces like van der Waals forces are included in the model, then agglomerate formation can be simulated, but the model complexity increases
Solution Approach 1:
The patent segments the complex many-body interaction problem into manageable components by focusing on pairwise force relationships between particles and agglomerates. By calculating van der Waals forces, collision forces, and drag forces as separate components that can be summed, the model captures cohesive effects without requiring simulation of all possible particle interactions simultaneously.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach improves the accuracy of simulating fluidized beds with Geldart group A particles by reducing inaccuracies associated with agglomerate formation and enhances the model's applicability to various fluidized bed systems by eliminating the need for arbitrary parameters, providing a more robust and versatile simulation of hydrodynamic behavior.
Implementation Method 1
accounting for forces like van der Waals, collision, and gravitational forces
Implementation Method 2
accounting for forces like van der Waals, collision, and gravitational forces
Implementation Method 3
updating drag relationships
Data Source
AI summary
A computer implemented method simulates the behavior of a gas-solid mixture in a fluidized bed having a particulate comprising Geldart group A particles using a Eulerian model comprising, for each time step (a current time step) and for each cell: obtaining an initial value of an agglomerate diameter corresponding to the cell and corresponding to the beginning of the current time step; performing a force-balance procedure for the cell to determine a first agglomerate diameter corresponding to the cell and corresponding to the current time step, wherein performing the force-balance procedure comprises determining a plurality of forces for the cell based at least in part on the initial value of the agglomerate diameter; updating one or more drag relationships for the current time step based at least in part on the first agglomerate diameter; and performing a computational fluid dynamic (CFD) solve procedure to determine, for the current time, the any one or more of: one or more of: a gas velocity {right arrow over (V)}g for the cell, a particle velocity {right arrow over (V)}s for the cell, a gas pressure for the cell, a particulate pressure for the cell and a solid fraction εs for the cell. Performing the CFD solve procedure is based at least in part on the updated drag relationships.