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Predictive Milling of a spiral jet mill using CFD-DEM

Researcher: Lewis Scott

Principal Investigator: Prof. Mojtaba Ghadiri

Co-Investigator(s): Dr Antonia Borissova, Dr Alan Burns

Industrial Supervisor(s): Dr Ian Gabbott, Dr Catherine Hallam

Project Sponsor(s): AstraZeneca

Status: 2017 – ongoing

Abstract

This project focuses on the numerical simulations of a spiral jet mill using CFD-DEM. The gas-solids interactions in the milling chamber are modelled. The history of individual particle movement and collisions are recorded. The project aims to develop a model capable of predicting the milled product particle size distribution. The scaling up of the mill is also of interest. The main issue with this technique is the computational overhead and time required when simulating a large number of very small particles. Hence, one section of the project considers how the particles may be scaled effectively to speed up the computations. Specific objectives within the project are as follows:

  • To what extent does the instantaneous amount of material (hold-up) in the main chamber affects its operation.
  • How to effectively scale the particles in the mill, so that their behaviour and the operation of the mill are not adversely affected.
  • Identify a method for applying a breakage model in the simulation for particle size reduction. Investigate the influence of particle properties during co-grinding; i.e. particle density and size.