Markov-chain modelling and experimental investigation of powder-mixing kinetics in static revolving mixers

International audienceThis study aims to develop a general model that is able to describe powder flow and mixing in static mixers, regardless of the type of mixer or the mixing configurations. The process model is based oil a homogeneous Markov chain describing the flow of each component through the mixing zone by a series of interconnected cells. It accounts for the number of mixing elements and their disposition in the mixer. as well as particle segregation via different transition probabilities. Some simulations are given to emphasize this particular aspect. Other outcomes of the model include the number of passages to reach a required mixture quality. as well as the asymptotic distribution of components. A laboratory static mixer of revolving type was designed specially for this study. It comprises up to 10 mixing sections, and its high internal voidage favours free flow of the powder. Segregating and non-segregating mixtures have been used to test the model and adjust unknown parameters. The model gives very satisfying results. In particular, it is able to account for the oscillating character of mixing kinetics due to particle segregation. It is also suggested that these parameters could be linked separately to powder flowability and mixing element characterization

A 2D Markov chain for modelling powder mixing in alternately revolving static mixers of Sysmix (R) type

International audienceA two-dimensional model of the flow and mixing of particulate solids has been developed on the basis of the Markov chain theory for an alternately revolving static mixer of Sysmix (R) type. In such a system, mixing occurs in both vertical and horizontal directions. Simulations are presented here to investigate the effect of the initial loading of the components, as well as the effect of the values of the transition probabilities that constitute the main parameters of the model. It is shown that a horizontal arrangement of the components always leads to better mixture quality and improved mixing kinetics. This research is presented for non-segregating mixtures, as well as potentially segregating mixtures. for which the empirically well-known oscillations in variance are represented by the model. Results suggest that there is a rational way of approaching a static-mixing problem with regard to the initial loading of the component and the optimal number of revolutions. Comparison of model results with experimental data published previously for a Sysmix (R) apparatus contributes to validating the viability of the model

Application of the theory of Markov chains to model the process of gravity classification

National audienc

Application of the theory of markovian chains to mathematical modeling of continuous mixing of granular materials

International audienc

Application of the theory of Markov chains to model mixing of granular materials

International audienc

Influence du type d'agitateur sur le fonctionnement et l'efficacité d'un mélangeur continu de solides divisés

National audienc

Experimental study of the stirring conditions taking place in pilot plant continuous mixer of particulate solids

National audienc

Application of the theory of markovian chains to modeling mechanical processes of chemical technology

International audienc

Mathematical model of the process of continuous mixing of granular materials

International audienceA mathematical model of continuous mixing in a drum blade mixer is proposed. The model is based on the theory of Markov chains and presupposes division of the operating volume into finite cells with transition probabilities between them. One and two-dimensional presentation of the operating volume is examined. The latter allows taking into account the crosswise segregation of components to be mixed. The formulae for calculation of the RTD curve as a response to the pulse injection of a tracer and all parameters (moments) of the curve are obtained for the both cases of modeling. Some numerical examples are shown to demonstrate the logic of the model and its efficiency

Application of the theory of markovian chains to modeling mechanical processes of chemical technology

International audienc