Application of simulation technologies in the analysis of granular material behaviour during transport and storage

Abstract

Problems in the preservation of the quality of granular material products are complex and arise from a series of sources during transport and storage. In either designing a new plant or, more likely, analysing problems that give rise to product quality degradation in existing operations, practical measurement and simulation tools and technologies are required to support the process engineer. These technologies are required to help in both identifying the source of such problems and then designing them out. As part of a major research programme on quality in particulate manufacturing computational models have been developed for segregation in silos, degradation in pneumatic conveyors, and the development of caking during storage, which use where possible, micro-mechanical relationships to characterize the behaviour of granular materials. The objective of the work presented here is to demonstrate the use of these computational models of unit processes involved in the analysis of large-scale processes involving the handling of granular materials. This paper presents a set of simulations of a complete large-scale granular materials handling operation, involving the discharge of the materials from a silo, its transport through a dilute-phase pneumatic conveyor, and the material storage in a big bag under varying environmental temperature and humidity conditions. Conclusions are drawn on the capability of the computational models to represent key granular processes, including particle size segregation, degradation, and moisture migration caking.

The development of a continuum framework for friction welding processes with the aid of micro-mechanical parameterisations

“…As has already been discussed, recent studies have shown a promising trend for the modelling of large-scale engineering processes where complex micromechanical phenomena play an important role, with the development of a continuum framework assisted by micromechanical parameterisations (see e.g. Chapelle et al, 2005). The development of a similar framework in the area of linear friction welding would be of great importance in the engineering community, as it will assist in the better understanding of material frictional behaviour and will enable the optimisation of linear friction welding processes.…”

“…This information is parametrised in the form of constitutive laws and utilised in the continuum model, thus making possible the representation of important processes, such as particle segregation, degradation and caking. The models for each process separately were first validated (Chapelle et al, 2004;Christakis et al, 2002;Wang et al, 2004) and then an integrated framework was set up (Chapelle et al, 2005), where all three models were combined in order to develop a toolkit for the simulation of full large-scale processes that involve granular material. The toolkit has been validated and is already in use by industry.…”

Analysis and modeling of heaping behavior of granular mixtures within a computational mechanics framework

“…The aim of this work is the numerical simulation of silo filling operations, including heap formation and predictions of segregation during filling. Recently, a continuum model was presented for the simulation of discharge from hoppers and good agreement was established between numerical predictions and available experimental data [7,8]. In the present work, this model is implemented with a more accurate description of particle interactions using a viscoplastic constitutive relation based on the Drucker-Prager plasticity yield function.…”

“…Despite the simplifications introduced, it has been shown that the model proposed above can reasonably reproduce the flow of granular materials discharging from a silo [7,8]. However, the model failed to describe complex features of granular materials flows, such as the heap building mechanism during filling of a silo.…”

A Hybrid Approach for the Modelling of Complex Systems: Methodologies and Applications

“…PROCESS All three models have been successfully validated using laboratory-scale equipment and benchmark tests (see e.g. [31], [48], [52]) and initial attempts have already been made for the application of the framework to the simulation of large scale processes involving granular materials ( [55][56]). In the present paper, in order to demonstrate the integrated HM strategy, a full simulation of a complete large scale handling process is presented.…”