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Fragmentation of fuel pellets during transport via a belt conveyor:A design of experiment study

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Particuology 2022年第7期20卷 29-37页

作者： Hamid Gilvari Coen H.H.van Battum Richard Farnish Yusong Pang Wiebren de Jong dingena l.schott Section of Transport Engineering and logistics Department of Maritime&Transport TechnologyFaculty of MechanicalMaritime and Materials EngineeringDelft University of TechnologyThe Netherlands Wolfson Centre for Bulk Solids Handling Technology Faculty of Engineering&ScienceUniversity of GreenwichUnited Kingdom Section of large Scale Energy Storage(lSE) Department of Process&EnergyFaculty of MechanicalMaritime and Materials EngineeringDelft University of TechnologyThe Netherlands

This work investigates the proportion of generated fines in a pilot-scale experiment using a belt conveyor and commercial fuel *** this,a belt conveyor with a length of 3.1 m was used and operated at varying conditions:speeds,percentages of material loading on the belt,two combinations of the inclination angle of the belt and the falling height,and a different number of handling *** considered a design of experiments approach based on response surface methodology to investigate the effect of different conditions on the potential of fines ***,a comparison between the results of the belt conveyor and three common benchmark experimental approaches(tumbling box,rotary impact tester,and mechanical compression test)was *** show that the number of handling steps and the combined effect of drop height and inclination angle directly affected the fines ***,the tested belt speed range and the level of loading were of lower significance.A polynomial quadratic model was derived based on the regression analysis and showed a high accuracy to predict the proportion of ***,the tumbling box method showed good potential to predict the proportion of fines in a belt conveyor when transported several times.

关键词： Fuel pellets Breakage Belt conveyor Transport Design of experiment Box–Behnken design

DEM speedup: Stiffness effects on behavior of bulk material

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Particuology 2014年第1期12卷 107-112页

作者： Stef lommen dingena schott Gabriel lodewijks Department of Maritime and Transport Technology Delft University of Technology

A number of techniques exist for minimizing the computational cost of discrete element simulations （DEMs）. One such method is a reduction of particle stiffness, which allows for bigger time steps and therefore fewer iterations in a simulation. However, the limits and drawbacks of this approach are still unclear, and may lead to invalid results. This paper investigates the effect of a stiffness reduction on bulk behavior by examining three case studies. Two cases demonstrate that particle stiffness can be reduced without affecting the bulk material behavior, whereas the third test shows that a stiffness reduction influences the bulk behavior.

关键词： Discrete element methodSpeedupStiffness reductionlimitOverlap

Modeling particle sedimentation in viscous fluids with a coupled immersed boundary method and discrete element method

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Particuology 2017年第2期15卷 191-199页

作者： Sayed M. Derakhshani dingena l. schott Gabriel lodewijks Faculty of Mechanical Maritime and Materials Engineering Delft University of Technology Delft Netherlands Department of Mechanical Engineering Faculty of Engineering University of Isfahan Isfahan Iran

Numerical techniques have increasingly been used to model fluid–particle two-phase flows. Coupling the immersed boundary method （IBM） and discrete element method （DEM） is one promising approach for modeling particulate flows. In this study, IBM was coupled with DEM to improve the reliability and accuracy of IBM for determining the positions of particles during the sedimentation process within viscous fluids. The required ratio of the particle diameter to the grid size （D/dx） was determined by comparing the simulation results with the analytical solution and experimental data. A dynamic mesh refinement model was utilised in the IBM model to refine the computational fluid dynamics grid near the particles. In addition, an optimum coupling interval between the IBM and DEM models was determined based on the experimental results of a single particle sedimentation within silicon oil at a Reynolds number of 1.5. The experimental results and the analytical solution were then utilised to validate the IBM–DEM model at Reynolds numbers of 4.1, 11.6, and 31.9. Finally, the validated model was utilised to investigate the sedimentation process for more than one particle by modeling the drafting-kissing-tumbling process and the Boycott phenomenon. Benchmark tests showed that the IBM–DEM technique preserves the advantages of DEM for tracking a group of particles, while the IBM provides a reliable and accurate approach for modeling the particle–fluid interaction.

关键词： Immersed boundary method Discrete element method Particle sedimentation Boycott phenomenon

Selection Methodology of High-Cycle Fatigue Analysis Approach for Damage Estimation in Welded Structural Joints

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Journal of Marine Science and Application 2022年第4期21卷 116-133页

作者： Skirmantas Pargalgauskas Xiaoli Jiang Marcel Edelkamp dingena schott Department of Maritime and Transport Technology Delft University of TechnologyDelft 2628CDNetherlands In Summa Inovation B.V. Raamsdonksveer 4941VVNetherlands

The main purpose of this paper is to provide a summarized general guideline to aid decision making of choosing the type of fatigue analysis approach,best suited for modelling and evaluating high-cycle fatigue damage in welded structural *** describes how addition of stress concentration and stress direction information into fatigue assessment methodology affect simulated fatigue damage accumulation results and when it is beneficial or necessary to use a particular fatigue damage estimation *** focus is on stress-life curve based approaches,particularly when deciding between variants of nominal,hot-spot or multiaxial fatigue assessment approaches for evaluating fatigue damage within welded joint *** is illustrated through application of proposed methodology to choose and perform fatigue assessment for a non-conventional load-bearing tubular joint structure within a floating lemniscate crane upper arm,which has been observed of being prone to aggressive crack propagation within its *** within the structure is estimated using two non-optimal fatigue analysis approaches to verify applicability of proposed selection *** are then summarized through comparative assessment and findings are discussed based on what leads to result changes within each fatigue damage analysis approach.

关键词： Fatigue analysis Multiaxial fatigue Hot-spot fatigue Methodology Welded joints

A Numerical Investigation of an Abnormal Phenomenon of Stress Intensity Factor(SIF)in a Cracked T-Butt Joint Accounting for Welding Effect

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Journal of Marine Science and Application 2021年第2期20卷 343-353页

作者： Matteo Schiaretti Jie Cai Xiaoli Jiang Shengming Zhang dingena schott Department of Maritime and Transport Technology Delft University of Technology2628 CD Delft The Netherlands Department of technology and innovation University of Southern DenmarkCampusvej 55DK-5230 Odense MDenmark lloyd's Register Global Technology Center SouthamptonUK

Industry design standards such as BS 7910 deployed some empirical formulas for the prediction of stress intensity factor(SIF) based on simulation results from traditional finite element method(FEM).However,such FEM simulation occasionally failed to convince people due to the large discrepancies compared with engineering *** a consequence,inaccuracy predictions via such formulas in engineering standards inevitably occur,which will compromise the safety of *** our previous research work,an abnormal phenomenon of SIF in a cracked T-butt joint accounting for welding effect has been *** with BS 7910,the calculation results of SIF at the surface points of welded specimens cannot be well predicted,with a large discrepancy *** order to explore such problem with an abnormal increase at the surface points of cracked welded specimens,a numerical investigation in terms of SIF among BS 7910,XFEM,and FEM is performed in this *** models on both a simple cracked plate without welding effect and a cracked T-butt joint with welding effect are developed through *** studies in terms of the effects of varied crack depth to thickness ratio(a/T) and the effects of crack depth to crack half-length ratio(a/c) are carried *** solutions from BS 7910 are used for *** is found that the XFEM can provide predictions of SIF at both the crack deepest point and crack surface point of a simple cracked plate as accurate as *** a T-butt joint with a transverse stiffener,a large discrepancy in terms of the weld magnification factors(Mk) occurs at the crack surface point compared with empirical *** exceptional increase of von Mises stress gradient in regions close to the weld-toe is found through the simulation of FEM,whereas a constant stress gradient is obtained through *** comparison results indicate an inappropriate prediction of SIF by the utilization of the empirical formulas in BS 7910.A more

关键词： Stress intensity factor(SIF) Crack T-butt joint BS 7910 Extended finite element method(XFEM) Finite element method(FEM)

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Preface

Particuology 2021年第6期19卷 1-1页

作者： dingena schott Harald Kruggel-Emden Kianoosh Taghizadeh Delft University of Technology The Netherlands Technical University Berlin Germany University ofTwente The Netherlands

Particle based modelling techniques have established itself as an important simulation tool within particle *** in the past,single phase solid flows have been in the focus in both academia and *** is changing towards ... 详细信息

关键词： technology. flows particle