The Experts below are selected from a list of 57207 Experts worldwide ranked by ideXlab platform
Wenyi Yan - One of the best experts on this subject based on the ideXlab platform.
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Shape optimization of conical Hoppers to increase mass discharging rate
Powder Technology, 2020Co-Authors: Xingjian Huang, Qijun Zheng, Wenyi YanAbstract:Abstract Mass discharging rate (MDR) is a critical aspect of Hopper’s performance in bulk solids handling. A shape optimization method is established in this study to increase the MDR of cohesionless granular materials from Hoppers. This method is based on a continuum model of granular matter and the Eulerian Finite Element Method (FEM) which can efficiently simulate the discharging process and predict the MDR. In this work with the focus on conical Hoppers, the widths of silo and Hopper outlet as well as the vertical height of Hopper are fixed. The meridian of the Hopper, however, evolves from a straight line to some optimal curve, guided by a combined genetic algorithm (GA) and gradient descent method (GDM). Cubic spline function is employed to parametrize the Hopper shape. The effectiveness of the shape optimization is examined by comparing the MDRs of the optimal Hopper and conventional conical Hopper, obtained by both FEM and discrete element method (DEM) respectively. It is shown that this shape optimization method can automatically search the optimal shape of the Hopper in a given range of constraints, and increase the MDR substantially. In a typical Hopper with an initial half angle of 45°, the MDR is increased by over 130% after the shape optimization. Notably, the optimal shape depends mainly on the geometrical factors, i.e. the allowed width and height for the Hopper, whilst insensitive to the material properties, which favors its general use for different particles. Such curved Hoppers are particularly useful for increasing the discharge rate of Hoppers ranging from 30° to 50°, which, facilitated with advanced manufacturing technology, will find wide potential applications in bulk solids handling.
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Optimised curved Hoppers with maximum mass discharge rate – an experimental study
Powder Technology, 1Co-Authors: Xingjian Huang, Qijun Zheng, Wenyi YanAbstract:Abstract This research experimentally studied the granular flow in the optimised curved Hoppers obtained from our recently published optimisation method. A series of optimised Hoppers were manufactured by CNC machining and an experimental apparatus was constructed to measure the MDR of various granular materials in the Hoppers. Our experiment confirmed that the MDR of the optimised curved Hoppers has increased more than 100% from that of those conventional conical Hoppers. The critical prefill level for reaching a steady discharge rate in the curved Hoppers is related to a fixed ratio to the diameter of the Hopper orifice, which increases with the initial half-angle of a curved Hopper. Three types of granular materials, i.e. rice, urea powders and sands, differing in shape, density and surface roughness, all gained improved MDR in the same curved Hoppers, which demonstrates the flexibility of the optimised curved Hoppers to maximize MDR for different granular materials.
Qijun Zheng - One of the best experts on this subject based on the ideXlab platform.
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Shape optimization of conical Hoppers to increase mass discharging rate
Powder Technology, 2020Co-Authors: Xingjian Huang, Qijun Zheng, Wenyi YanAbstract:Abstract Mass discharging rate (MDR) is a critical aspect of Hopper’s performance in bulk solids handling. A shape optimization method is established in this study to increase the MDR of cohesionless granular materials from Hoppers. This method is based on a continuum model of granular matter and the Eulerian Finite Element Method (FEM) which can efficiently simulate the discharging process and predict the MDR. In this work with the focus on conical Hoppers, the widths of silo and Hopper outlet as well as the vertical height of Hopper are fixed. The meridian of the Hopper, however, evolves from a straight line to some optimal curve, guided by a combined genetic algorithm (GA) and gradient descent method (GDM). Cubic spline function is employed to parametrize the Hopper shape. The effectiveness of the shape optimization is examined by comparing the MDRs of the optimal Hopper and conventional conical Hopper, obtained by both FEM and discrete element method (DEM) respectively. It is shown that this shape optimization method can automatically search the optimal shape of the Hopper in a given range of constraints, and increase the MDR substantially. In a typical Hopper with an initial half angle of 45°, the MDR is increased by over 130% after the shape optimization. Notably, the optimal shape depends mainly on the geometrical factors, i.e. the allowed width and height for the Hopper, whilst insensitive to the material properties, which favors its general use for different particles. Such curved Hoppers are particularly useful for increasing the discharge rate of Hoppers ranging from 30° to 50°, which, facilitated with advanced manufacturing technology, will find wide potential applications in bulk solids handling.
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prediction of mass discharge rate in conical Hoppers using elastoplastic model
Powder Technology, 2017Co-Authors: Qijun Zheng, Aibing YuAbstract:Abstract Precise evaluation of mass discharge rate (MDR) in Hoppers is an important topic in many industries. Facilitated by an Eulerian-formulation finite element method (FEM), this paper uses an elastoplastic model to investigate the MDR in conical Hoppers and evaluates its applicability in various cases of Hopper geometries and material properties. The obtained flow field complies with the scaling of outlet velocity V y ~ gD 0 and that of the discharge rate MDR ~ g D 0 5 / 2 universally. The MDR is basically independent of the fill height and silo width, but a strong height dependency may emerge for very small internal friction angle of granular material, similar to the fluid-like discharging observed in previous DEM simulation. As for the material properties, the MDR is mainly controlled by the plastic parameters such as internal friction angle and dilation but is insensitive to the elastic modulus. The quantitative accuracy of the model is verified by comparing experimental measurements and discrete simulation over a wide range of Hopper half angles. The existing correlations are often conditionally applicable in describing MDR – some for steep Hoppers while others mainly suitable for shallow ones. An empirical correlation is formulated based on the FEM results to achieve a general applicability, which may help to improve the Hopper design in practical applications. The needs for future research are also discussed.
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Optimised curved Hoppers with maximum mass discharge rate – an experimental study
Powder Technology, 1Co-Authors: Xingjian Huang, Qijun Zheng, Wenyi YanAbstract:Abstract This research experimentally studied the granular flow in the optimised curved Hoppers obtained from our recently published optimisation method. A series of optimised Hoppers were manufactured by CNC machining and an experimental apparatus was constructed to measure the MDR of various granular materials in the Hoppers. Our experiment confirmed that the MDR of the optimised curved Hoppers has increased more than 100% from that of those conventional conical Hoppers. The critical prefill level for reaching a steady discharge rate in the curved Hoppers is related to a fixed ratio to the diameter of the Hopper orifice, which increases with the initial half-angle of a curved Hopper. Three types of granular materials, i.e. rice, urea powders and sands, differing in shape, density and surface roughness, all gained improved MDR in the same curved Hoppers, which demonstrates the flexibility of the optimised curved Hoppers to maximize MDR for different granular materials.
Aibing Yu - One of the best experts on this subject based on the ideXlab platform.
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prediction of mass discharge rate in conical Hoppers using elastoplastic model
Powder Technology, 2017Co-Authors: Qijun Zheng, Aibing YuAbstract:Abstract Precise evaluation of mass discharge rate (MDR) in Hoppers is an important topic in many industries. Facilitated by an Eulerian-formulation finite element method (FEM), this paper uses an elastoplastic model to investigate the MDR in conical Hoppers and evaluates its applicability in various cases of Hopper geometries and material properties. The obtained flow field complies with the scaling of outlet velocity V y ~ gD 0 and that of the discharge rate MDR ~ g D 0 5 / 2 universally. The MDR is basically independent of the fill height and silo width, but a strong height dependency may emerge for very small internal friction angle of granular material, similar to the fluid-like discharging observed in previous DEM simulation. As for the material properties, the MDR is mainly controlled by the plastic parameters such as internal friction angle and dilation but is insensitive to the elastic modulus. The quantitative accuracy of the model is verified by comparing experimental measurements and discrete simulation over a wide range of Hopper half angles. The existing correlations are often conditionally applicable in describing MDR – some for steep Hoppers while others mainly suitable for shallow ones. An empirical correlation is formulated based on the FEM results to achieve a general applicability, which may help to improve the Hopper design in practical applications. The needs for future research are also discussed.
William R Ketterhagen - One of the best experts on this subject based on the ideXlab platform.
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predicting discharge dynamics of wet cohesive particles from a rectangular Hopper using the discrete element method dem
Chemical Engineering Science, 2009Co-Authors: Anshu Anand, Jennifer S Curtis, Carl Wassgren, Bruno C Hancock, William R KetterhagenAbstract:Accurate prediction of the discharge rate from Hoppers is important in many industrial processes involving the handling of granular materials. The present work investigates the parameters affecting the discharge rate of a wet cohesive system from a quasi-3-D, rectangular Hopper using the discrete element method (DEM). The cohesion between the particles is described by a pendular liquid bridge force model and the strength of the cohesive bond is characterized by a Bond number. The Beverloo correlation is applied to cohesive systems by modifying the Beverloo constant as a function of Bond number. The predictions obtained from this modified correlation fit the simulation data reasonably well. In addition, the effect of Hopper angle in cohesive systems is shown to follow a trend similar to cohesionless systems, where the discharge rate is insensitive to changes in Hopper angle except below a critical angle (with respect to the vertical) where the discharge rate increases rapidly. This critical angle of flow decreases with increasing cohesion.
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predicting discharge dynamics from a rectangular Hopper using the discrete element method dem
Chemical Engineering Science, 2008Co-Authors: Anshu Anand, Jennifer S Curtis, Carl Wassgren, Bruno C Hancock, William R KetterhagenAbstract:Accurate prediction of the discharge rate from Hoppers is important in many industrial processes involving the handling of granular materials. The present work investigates the parameters affecting the discharge rate using the discrete element method (DEM). The effects of particle properties (particle size and size distribution) and Hopper geometry (Hopper width, outlet width, angle and fill height) are studied and compared to previously published experimental correlations. The results indicate that DEM simulations are fully capable of reproducing trends in the discharge rate that are well-known experimentally. For example, particle size and Hopper width are shown to have a minimal influence on the discharge rate. In addition, for rectangular Hoppers, the discharge rate is shown to vary with the outlet width raised to the 32 power as given by the modified Beverloo correlation. The DEM simulations are also used to explore a wider range of parameters that have not been or are not easily explored experimentally. For example, the effects of Hopper friction, particle friction, coefficient of restitution are investigated, and particle friction is shown to have a significant influence on the Hopper discharge behavior.
E C Synnott - One of the best experts on this subject based on the ideXlab platform.
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characterisation of food powder flowability
Journal of Food Engineering, 1999Co-Authors: E Teunou, John J Fitzpatrick, E C SynnottAbstract:This paper presents a characterisation of the flow properties of four food powders (flour, skim-milk, tea and whey-permeate). Physical property measurements, including particle size, bulk and particle densities, water sorption isotherms and DSC thermograms, are presented. Powder flowability was measured using an annular shear cell. The flowability of the 4 food powders are compared and discussed with reference to their physical properties and the relative humidity of the surrounding atmosphere. One application of powder flowability data is in the design of Hoppers. Different failure properties from shear tests are calculated for each of the food powders. They are then applied to estimating and comparing the critical Hopper dimensions for mass flow for each powder.
