Simulation of iron ore pellets and powder flow using smoothed particle method
Abstract (Summary)Handling of iron ore pellets is an important part in the converting process for LKAB. Knowledge about this sub process is very important for further efficiency progress and increased product quality. The existence of a simulation tool with modern modelling and simulation methods will significantly increase the possibility to predict the critical forces in product development processes and thereby decrease the amount of crushed pellets (fines). In this work, simulations of granular material flows on a global scale are performed. From the simulations, properties like flow pattern and density distribution are studied. The methodology is suitable for different applications of particle flows. The particles could be stones, ore, ore pellets, metal powder and other granular materials. Previous studies exploring flow patterns and stress fields in granular solids are analysed with experiments or with numerical methods such as discrete element (DE) method or finite element (FE) computations. In this work, the smoothed particle (SP) method is used to simulate granular material flow. It is a mesh-free continuum-based computational technique where each calculation node is associated with a specific mass, momentum and energy. Properties within the flow such as density and movements of the nodes results from summations via a kernel function of the neighbours of each node to solve the integration of the governing equations. The fact that there are no connections between the nodes in the SP method, results in a method that handles extremely large deformations and still has the advantages of a continuum-based method. This is a major advantage versus FE and DE analysis. Within the current thesis, two applications of simulating granular material with SP analysis is presented: iron ore pellets flow in a flat bottomed silo and simulation of shoe filling of metal powder into simple and stepped dies. In the first application, primarily the flow pattern, when discharging a silo with pellets, is studied and compared with experimental results. Next application focuses on the filling behaviour and density distribution in metal powder shoe filling. For trustworthy numerical simulations of iron ore pellets flow, knowledge about their mechanical properties is needed. In this work, an elastic-plastic material characterization for blast furnace pellets is evaluated from experimental data. Constitutive data in vein of two elastic parameters and a yield function for the pellets bulk material is determined. The present study is an important step towards a simulation tool to predict the critical load in different handling systems of pellets.
School:Luleå tekniska universitet
Source Type:Master's Thesis
Date of Publication:01/01/2008