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Centre Capabilities

Material Handling: An integrated computational framework for materials handling

Centre staff have collaborated in developing CFD modelling techniques for particulate based manufacturing and handling processes to predict segregation (particle size and blend components), caking (lump formation preventing free flow) and degradation (particle breakage) in the handling of particulate material. While primarily a collaboration between Wolfson and CSEG, CFD technology and concepts developed in this project are being utilised by FSEG and CMRG.

Project Optimisation Diagram

Particulate based manufacturing and handling technology is an integral element of a substantial proportion of the UK process industry and includes foods, pharmaceuticals, chemicals, minerals, and energy related products of all kinds. More than a third of all UK process plants involve the handling and /or processing of polydisperse particulate solids. Despite their huge importance, each of these sectors manages its particulate technology in a largely empirical manner. As such, process control, efficiency and resulting product quality are frequently compromised; a fact identified by the Foresight Manufacturing 2020 Panel.

Despite significant past efforts to research aspects of particulate based manufacturing and handling processes, numerous industrial problems still exist, arising from a lack of operational reliability coupled with variable product quality. These problems typically arise from one or more of the following: segregation (particle size and bled components), caking (lump formation preventing free flow) and degradation (particle breakage). The prime objective of the "Quality in Particulate Manufacturing" (QPM) project was to integrate a range of analytical and process modelling tools with laboratory based experiments in order to design out, or minimise, the key problems which compromise the operation of granular materials based operation and the quality of the resulting products.

The distinctive focus of the project has been to take a holistic view and employ phenomenological tools, rather than empirical based methods, as the basis for process engineering design and optimisation strategies. This has resulted in a CFD modelling framework which includes the behaviour of granular materials, where the particle micro-mechanical behaviour in a multi-component granular mixture is parametrised, via a series of controlled experiments performed by the Wolfson Centre, which are employed in the form of constitutive models. CSEG, in collaboration with the Wolfson Centre, has incorporated these constitutive relationships within a CFD framework providing a means to predict bulk material behaviour.

These CFD based models are used to predict key transport processes in granular materials, namely particle size segregation, degradation due to impact, and caking due to moisture migration. The underlying characterizations and parameterizations procedures, together with the developed models, were integrated within a modelling framework, which resulted in three Toolkits. The Toolkits have been applied to a series of single component processes through to complete large scale processes that handle granular materials. The Toolkits can be used to understand the "key" points within the handling process as to what could be compromising "Quality" of the material; for example the modelling of segregation effects during the discharge of a hopper, degradation due to impact of particles on pipe bends during dilute phase pneumatic conveying, and moisture migration caking phenomena in storage/transportation.

CSEG is coupling the constitutive models in the multi-physics micro-mechanical modelling framework provided by the PHYSICA software. CFD modelling techniques developed in this area, such as the handling of multiphase materials, can also prove useful in fire simulation where particle tracking procedures are used for the simulation of water mist and sprinkler suppression systems. This expertise is being utilised by FSEG in the development of the SMARTFIRE software. CMRG is benefiting from this technology as a number of materials used in packaging of electronic components are pastes with a high particle content. The flow and packing of these materials into small apertures can be modelled using PHYSICA with some of the techniques developed within the QPM project.