CFD-DEM modelling of gas-solid reacting flow (rCFD-DEM): from new approaches to industry applications

Numerical methods such as the discrete element method (DEM), computational fluid dynamics (CFD), coupled CFD-DEM, and multiphase particle-in-cell (MP-PIC) simulations provide potentially powerful tools for the investigation and optimisation of fluidised beds and other multiphase systems. However, without rigorous calibration and validation, their outputs may be inaccurate, or even entirely unphysical. The process of calibration can, however, prove highly time- and labour-intensive, and both calibration and validation are sorely lacking a clearly-defined "Best Practice".

In this talk, we introduce novel methods for both the calibration and validation of numerical simulations of fluidised- and spouted-bed systems, both of which can be easily generalised to other particulate, fluid or multiphase systems, and to arbitrary simulation techniques.

In part 1 of the talk we introduce Autonomous Characterisation and Calibration using Evolutionary Simulation (ACCES), an open-source, AI-based tool which uses evolutionary computation and metaprogramming to autonomously determine the correct calibration parameters for a given simulation based only on data readily available from widely-available powder characterisation tools.

in part 2, we introduce Positron Emission Particle Tracking (PEPT), a nuclear imaging technique which allows the fully-three-dimensional dynamics of diverse particulate and multiphase systems to be imaged with sub-millimetre spatial resolution and sub-millisecond temporal resolution, even deep within the interior of large, dense, optically opaque systems. We show how the detailed, three-dimensional fields extracted from PEPT data may be used to provide a uniquely rigorous validation of simulation methods such as CFD, DEM and MP-PIC.

We demonstrate the application of both methodologies using a series of case studies involving both laboratory and industrial systems, including spouted-bed coffee roasters and fluidised-bed-based pyrolysis reactors for the chemical recycling of plastic waste.