Modelling bulk solid flow interactions in transfer chutes: shearing flow

In the field of handling, storage and transportation, chutes are used to transfer bulk solids between conveyors. In these systems, traditional analysis methods based on the principle of continuum mechanics approximate an accelerated stream that incorporates physical bulk solid properties obtained from standardised tests. Due to difficulties in physically observing the flow within the transfer structure, verification of the method at full scale is scarcely reported. In contrast, Discrete Element Modelling (DEM) allows flow visualization through a transfer chute and enables qualitative and quantitative analysis provided accurate simulation parameters are selected. This paper presents application of the two methods in a real life high throughput installation using a case study comprising of a stacker chute system transferring coal from one incoming conveyor to one outgoing (boom) conveyor. The flow analysed is representative of transfer configurations characterised by a re-directed fast moving, high volume stream in restricted space, where the mode of flow is governed by internal (shear) properties of the bulk solid material. For the study, the velocity of the coal stream on the outgoing conveyor at loading is significantly lower compared to both the incoming and outgoing conveyor belt speeds. In the study presented, application of the traditional and a modified continuum method approach is compared to DEM simulations and site observations. A sensitivity analysis of modelling parameters is also provided.