The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Hubert Chanson - One of the best experts on this subject based on the ideXlab platform.
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application of optical flow methods to aerated skimming flows above triangular and trapezoidal step cavities
Journal of Hydraulic Research, 2019Co-Authors: Gangfu Zhang, Hubert ChansonAbstract:Stepped Chutes are built to provide safe flood passage in dams. The steps are associated with strong turbulence generation, which allow air to be entrained from the free surface. The present work a...
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simple design criterion for residual energy on embankment dam stepped spillways
Journal of Hydraulic Engineering, 2016Co-Authors: Stefan Felder, Hubert ChansonAbstract:AbstractThe stepped spillway design is associated with significant flow resistance and associated energy dissipation on the steps, yielding smaller, more economical downstream dissipation structures. A number of design guidelines were developed for steep stepped spillways typical of concrete gravity dams. The focus of this study is on embankment stepped spillways. A large set of air-water flow data is compared with reanalyzed data sets to provide a simple unifying design approach for the residual energy at the stepped chute’s downstream end and to highlight the uncertainties involved. The results provided some simple design criteria in terms of the dimensionless residual energy of stepped Chutes with flat steps. It is believed that a stepped design with a 1V:2.5H slope (θ=21.8°) might be optimum in terms of energy dissipation performances. The Darcy-Weisbach friction factors were close for all stepped data ranging between 0.1≤fe≤0.4.
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energy dissipation on embankment dam stepped spillways overflow stepped weirs and masonry stepped spillways
17th Congress of IAHR Asia and Pacific Division IAHR-APD, 2010Co-Authors: Hubert Chanson, Stefan FelderAbstract:Stepped spillways are designed to increase the rate of energy dissipation on the chute reducing the size of a downstream energy dissipator. The prediction of the turbulent dissipation above the steps constitutes a critical part of the design process, especially at large discharges per unit width corresponding to the skimming flow regime. Herein new measurements were conducted in a large facility with a channel slope of 26.6o and step heights of 0.10 m. The experiments were performed with large discharges corresponding to Reynolds numbers ranging from 5×10 4 to 1×10 6 . The waters were highly turbulent and they dissipated a major proportion of the flow kinetic energy. Taking into account the free-surface aeration, the present results were compared with recent results on 15.9o and 21.8o slopes; the range of slopes (1V:3.5H to 1V:2H) was typical of embankment slopes and older spillway designs. The comparative results yielded some simple design guidelines applicable to masonry stepped spillways, embankment dam stepped Chutes and overflow stepped weirs.
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turbulence and cavity recirculation in air water skimming flows
Journal of Hydraulic Research, 2008Co-Authors: Carlos A Gonzalez, Hubert ChansonAbstract:Current expertise in air–water turbulent flows on stepped Chutes is limited mostly to laboratory experiments at low to moderate Reynolds numbers on Chutes with flat horizontal steps. In this study, highly turbulent air–water flows skimming down a large-size stepped chute were investigated with a 1V:2.5H slope. For some experiments, the cavity recirculation was controlled using triangular vanes, or longitudinal ribs, to enhance the interactions between the skimming flow and cavity recirculating region. New experiments were performed with seven configurations. The results demonstrated the strong influence of the vanes on the cavity recirculation patterns and on the air–water flow properties. An increase in flow resistance was observed consistently with maximum rate of energy dissipation achieved with vanes placed in a zigzag pattern.
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Flow patterns in nappe flow regime down low gradient stepped Chutes
Journal of Hydraulic Research, 2008Co-Authors: Luke Toombes, Connell Wagner, Hubert ChansonAbstract:Although modern gravity dam spillways include often steep Chutes operating in skimming flow regime, succession of free-falling nappes (i.e. nappe flow regime) are more common on low gradient Chutes and cascades, and this flow situation received little attention to date. New experiments were conducted in nappe flows without hydraulic jump in two large-size facilities with flat slopes. The flow on the stepped cascade displayed complex, three-dimensional patterns. Detailed air–water flow measurements were performed in the jet, at nappe impact and in the downstream flow region. Key results demonstrated that the flow on each step was rapidly varied, highly three-dimensional and strongly aerated.
A W Roberts - One of the best experts on this subject based on the ideXlab platform.
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modelling bulk solid interactions in transfer Chutes accelerated flow
Chemical Engineering Science, 2019Co-Authors: Dusan Ilic, A W Roberts, Craig WheelerAbstract:Abstract The continuum method is an approach to model transfer Chutes characterised by accelerated flow conditions, with origins stemming from free flowing materials. Physical bulk solid properties obtained through laboratory tests are incorporated and the focus is to maintain a rapidly moving stream, with minimum variation in velocity across the burden depth. Due to structural elements, it is difficult to quantify flow occurring inside and as such, accurate site validation is scarce. Discrete Element Modelling (DEM) provides a solution enabling flow visualisation, and a unique means of both qualitative and quantitative analyses. This paper presents application of both methods in a real high throughput installation comprising a bifurcated chute arrangement transferring coal from one delivery conveyor to two receiving conveyors. The results show that both methods can model the type of flow exhibited and presented is a comparison between qualitative site observations and material flow profiles calculated using each method.
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modelling bulk solid flow interactions in transfer Chutes shearing flow
Powder Technology, 2019Co-Authors: Dusan Ilic, Craig Wheeler, A W Roberts, Andre KatterfeldAbstract:Abstract 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.
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abrasion wear resistance of wall lining materials in bins and Chutes during iron ore mining
International Journal of Mineral Processing, 2017Co-Authors: Wei Chen, A W Roberts, Subhankar Biswas, Jayne Oshea, Kenneth WilliamsAbstract:Abstract The wear problem on the internal lining of bins and Chutes needs to be addressed before any significant efficiency gains during iron ore mining operations. This study aims to investigate the factors determining the wear resistance of common lining materials used in iron ore mining operations. A purposely designed experimental system was utilised to quantitatively assess the wear resistance of a suite of wall lining materials against an iron ore abrading medium, from which a wear rate for each liner is determined. Results suggested that the hardness of a lining material can be utilised to indicate its abrasion wear resistance. From experimental results, prediction models of the service life of selected lining materials in bins and Chutes are also obtained.
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evaluation of dust emissions from conveyor transfer Chutes using experimental and cfd simulation
International Journal of Mineral Processing, 2012Co-Authors: X L Chen, Craig Wheeler, T J Donohue, Rachael Mclean, A W RobertsAbstract:Abstract This paper focuses on a study concerned with reducing dust emissions from belt conveyor transfer Chutes in bulk material handling plants. Several transfer chute configurations were investigated with the aim of analysing the system performance. Scale model laboratory testing was undertaken to determine the effectiveness of each design in reducing dust emission. Computational Fluid Dynamics (CFD) was used to investigate the flow pattern of the granular material and entrained air in each of the transfer chute configurations. To verify the feasibility of CFD for dust emission prediction, a two-phase three-dimensional Euler–Euler model was adopted to qualitatively predict the performance of six transfer chute configurations with respect to dust generation. The predicted dust emissions obtained from the simulations were compared with the scale model test results. The simulation predictions compared favourably with the experimental results, demonstrating that CFD can be used to qualitatively evaluate the performance of transfer chute designs with regard to dust emission.
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prediction of lining wear life of bins and Chutes in bulk solids handling operations
Tribology International, 1993Co-Authors: A W Roberts, S J WicheAbstract:Abstract This paper is concerned with the prediction of lining wear life of bins and Chutes in bulk solids handling plant. It focuses on abrasive wear and outlines the basic principles to be embodied in the development of a laboratory wear tester. Emphasis is given to a linear action wear tester developed jointly by the University of Twente, The Netherlands, and the University of Newcastle, Australia. The characteristics of abrasive wear in bins, hoppers and Chutes are described and the application of test results to the prediction of wear life of lining materials is illustrated.
Dusan Ilic - One of the best experts on this subject based on the ideXlab platform.
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modelling bulk solid interactions in transfer Chutes accelerated flow
Chemical Engineering Science, 2019Co-Authors: Dusan Ilic, A W Roberts, Craig WheelerAbstract:Abstract The continuum method is an approach to model transfer Chutes characterised by accelerated flow conditions, with origins stemming from free flowing materials. Physical bulk solid properties obtained through laboratory tests are incorporated and the focus is to maintain a rapidly moving stream, with minimum variation in velocity across the burden depth. Due to structural elements, it is difficult to quantify flow occurring inside and as such, accurate site validation is scarce. Discrete Element Modelling (DEM) provides a solution enabling flow visualisation, and a unique means of both qualitative and quantitative analyses. This paper presents application of both methods in a real high throughput installation comprising a bifurcated chute arrangement transferring coal from one delivery conveyor to two receiving conveyors. The results show that both methods can model the type of flow exhibited and presented is a comparison between qualitative site observations and material flow profiles calculated using each method.
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development of design criteria for reducing wear in iron ore transfer Chutes
Wear, 2019Co-Authors: Dusan IlicAbstract:Abstract In high throughput Australian iron ore handling operations, premature failure of conveyor belts and transfer Chutes due to wear is of great significance to the success of operations. Here, a down time in the order of a few hours may result in millions of tonnes of annual export losses. Optimisation of existing or brownfield high capacity and utilisation mine, plant and port facilities with minimial capital spend has not always reduced maintenance costs. Gauging the success of such endevours allows for the establishment of design standards that are becoming accepted by the iron ore industry. The aim of these standards is to improve functionality and maximise the service life of installed equipment without compromising flow performance. This paper outlines key criteria for design standards, with a focus on minimising conveyor transfer and belt wear, that can be integrated into an existing frawework of engineering management in iron ore operations. Research and industry experience are blended with a theoretical (continuum mechancis based) and numerical (Discrete Element Method based) modelling assessment. A qualitative modelling case study is presented investigating the sensitivities associated with transfer chute design geometry and the resulting chute and belt wear life. An outline of the elements for consideration towards design criteria specification in iron ore transfers is presented. Such specifications must result in adequacy of the designed transfer to meet both technical and functional requirements across the range of operational conditions and variation of the characteristics of the ores handled.
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modelling bulk solid flow interactions in transfer Chutes shearing flow
Powder Technology, 2019Co-Authors: Dusan Ilic, Craig Wheeler, A W Roberts, Andre KatterfeldAbstract:Abstract 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.
Craig Wheeler - One of the best experts on this subject based on the ideXlab platform.
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modelling bulk solid interactions in transfer Chutes accelerated flow
Chemical Engineering Science, 2019Co-Authors: Dusan Ilic, A W Roberts, Craig WheelerAbstract:Abstract The continuum method is an approach to model transfer Chutes characterised by accelerated flow conditions, with origins stemming from free flowing materials. Physical bulk solid properties obtained through laboratory tests are incorporated and the focus is to maintain a rapidly moving stream, with minimum variation in velocity across the burden depth. Due to structural elements, it is difficult to quantify flow occurring inside and as such, accurate site validation is scarce. Discrete Element Modelling (DEM) provides a solution enabling flow visualisation, and a unique means of both qualitative and quantitative analyses. This paper presents application of both methods in a real high throughput installation comprising a bifurcated chute arrangement transferring coal from one delivery conveyor to two receiving conveyors. The results show that both methods can model the type of flow exhibited and presented is a comparison between qualitative site observations and material flow profiles calculated using each method.
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modelling bulk solid flow interactions in transfer Chutes shearing flow
Powder Technology, 2019Co-Authors: Dusan Ilic, Craig Wheeler, A W Roberts, Andre KatterfeldAbstract:Abstract 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.
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evaluation of dust emissions from conveyor transfer Chutes using experimental and cfd simulation
International Journal of Mineral Processing, 2012Co-Authors: X L Chen, Craig Wheeler, T J Donohue, Rachael Mclean, A W RobertsAbstract:Abstract This paper focuses on a study concerned with reducing dust emissions from belt conveyor transfer Chutes in bulk material handling plants. Several transfer chute configurations were investigated with the aim of analysing the system performance. Scale model laboratory testing was undertaken to determine the effectiveness of each design in reducing dust emission. Computational Fluid Dynamics (CFD) was used to investigate the flow pattern of the granular material and entrained air in each of the transfer chute configurations. To verify the feasibility of CFD for dust emission prediction, a two-phase three-dimensional Euler–Euler model was adopted to qualitatively predict the performance of six transfer chute configurations with respect to dust generation. The predicted dust emissions obtained from the simulations were compared with the scale model test results. The simulation predictions compared favourably with the experimental results, demonstrating that CFD can be used to qualitatively evaluate the performance of transfer chute designs with regard to dust emission.
Antonio Piersanti - One of the best experts on this subject based on the ideXlab platform.
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stresses at the base of dry and dense flows of angular rock fragments in 3 d discrete element modeling scaling of basal stress fluctuations versus grain size flow volume and channel width
Journal of Volcanology and Geothermal Research, 2018Co-Authors: Bruno Cagnoli, Antonio PiersantiAbstract:Abstract We simulate granular flows of angular rock fragments by means of a three-dimensional discrete element modeling to study the basal stresses that these flows exert on the subsurface. These granular flows have different grain sizes and different flow volumes and they model dry rock avalanches and dense pyroclastic flows. These flows travel on four different concave–upward Chutes that represent channels on a mountainside or on the flank of a volcano. Each chute has a different width. The stress data demonstrate the validity of a linear relation between two scaling parameters: D and ψ . Parameter D is a scaled basal stress deviation that is equivalent to a scaled particle agitation. Particle agitation is ultimately responsible for the energy dissipation that governs the mobility of dense geophysical flows in nature. Parameter ψ contains grain size, flow volume and channel width. This second parameter is equal to the product of the reciprocal of characteristic numbers of fragments in granular flows. Since these numbers of particles are dimensionless, the linear relation is valid at any scale, either in the laboratory or in nature.