scholarly journals Capturing heat transfer for complex-shaped multibody contact problems, a new FDEM approach

2020 ◽  
Vol 7 (5) ◽  
pp. 919-934 ◽  
Author(s):  
Clément Joulin ◽  
Jiansheng Xiang ◽  
John-Paul Latham ◽  
Christopher Pain ◽  
Pablo Salinas
Keyword(s):  
Heat Transfer ◽  
Particle System ◽  
Contact Problems ◽  
Discrete Element ◽  
Fem Model ◽  
New Approach ◽  
Inherent Feature ◽  
Solid Bodies ◽  
Multibody Contact ◽  
Element Method

Abstract This paper presents a new approach for the modelling of heat transfer in 3D discrete particle systems. Using a combined finite–discrete element (FDEM) method, the surface of contact is numerically computed when two discrete meshes of two solids experience a small overlap. Incoming heat flux and heat conduction inside and between solid bodies are linked. In traditional FEM (finite element method) or DEM (discrete element method) approaches, to model heat transfer across contacting bodies, the surface of contact is not directly reconstructed. The approach adopted here uses the number of surface elements from the penetrating boundary meshes to form a polygon of the intersection, resulting in a significant decrease in the mesh dependency of the method. Moreover, this new method is suitable for any sizes or shapes making up the particle system, and heat distribution across particles is an inherent feature of the model. This FDEM approach is validated against two models: a FEM model and a DEM pipe network model. In addition, a multi-particle heat transfer contact problem of complex-shaped particles is presented.

The Granule Mechanic Model for Numerical Simulation of Coal Stream in Coal-Fired Power Plant

2010 ◽  
Vol 34-35 ◽  
pp. 1383-1387
Author(s):  
Hui Chun Peng ◽  
Qing He
Keyword(s):  
Numerical Simulation ◽  
Power Plant ◽  
Discrete Element Method ◽  
Particle System ◽  
Discrete Element ◽  
Mechanic Model ◽  
Contact Models ◽  
Element Method

In this paper, the contact models of particle system of coal stream are analyzed; the granule mechanic models of coal stream in different imposed conditions are summarized. Using 3d-discrete element method, a particle mechanic model of clumps is constructed by the contact bonding model to simulate the cataclasm phenomena during the coal conveying of Coal-fired power plant, which plays an important role in assuring the fidelity and integrality of 3D virtual coal conveying scene.

Predicting Skin Friction and Heat Transfer for Turbulent Flow Over Real Gas-Turbine Surface Roughness Using the Discrete-Element Method

2003 ◽  
Author(s):  
Stephen T. McClain ◽  
B. Keith Hodge ◽  
Jeffrey P. Bons
Keyword(s):  
Heat Transfer ◽  
Surface Roughness ◽  
Wind Tunnel ◽  
Discrete Element Method ◽  
Skin Friction ◽  
Gas Turbine ◽  
Discrete Element ◽  
Real Gas ◽  
Roughness Elements ◽  
Element Method

The discrete-element method considers the total aerodynamic drag on a rough surface to be the sum of shear drag on the flat part of the surface and the form drag on the individual roughness elements. The total heat transfer from a rough surface is the sum of convection through the fluid on the flat part of the surface and the convection from each of the roughness elements. The discrete-element method has been widely used and validated for predicting heat transfer and skin friction for rough surfaces composed of sparse, ordered, and deterministic elements. Real gas-turbine surface roughness is different from surfaces with sparse, ordered, and deterministic roughness elements. Modifications made to the discrete-element roughness method to extend the validation to real gas-turbine surface roughness are detailed. Two rough surfaces found on high-hour gas-turbine blades were characterized using a Taylor-Hobson Form Talysurf Series 2 profilometer. Two rough surfaces and two elliptical-analog surfaces were generated for wind-tunnel testing using a three-dimensional printer. The printed surfaces were scaled to maintain similar boundary-layer thickness to roughness height ratio in the wind tunnel as found in gas-turbine operation. The results of the wind tunnel skin friction and Stanton number measurements and the discrete-element method predictions for each of the four surfaces are presented and discussed. The discrete-element predictions made considering the gas-turbine roughness modifications are within 7% of the experimentally-measured skin friction coefficients and are within 16% of the experimentally-measured Stanton numbers.

Fretting Wear Modeling of Coated and Uncoated Surfaces Using the Combined Finite-Discrete Element Method

2011 ◽  
Vol 133 (2) ◽  
Author(s):  
Benjamin D. Leonard ◽  
Pankaj Patil ◽  
Trevor S. Slack ◽  
Farshid Sadeghi ◽  
Sachin Shinde ◽  
...  
Keyword(s):  
Discrete Element Method ◽  
Normal Force ◽  
Discrete Element ◽  
Fretting Wear ◽  
Wear Loss ◽  
New Approach ◽  
Frictional Shear Stress ◽  
Algorithm Stability ◽  
Force Displacement ◽  
Element Method

A new approach for modeling fretting wear in a Hertzian line contact is presented. The combined finite-discrete element method (FDEM) in which multiple finite element bodies interact as distinct bodies is used to model a two-dimensional fretting contact with and without coatings. The normal force and sliding distance are used during each fretting cycle, and fretting wear is modeled by locally applying Archard’s wear equation to determine wear loss along the surface. The FDEM is validated by comparing the pressure and frictional shear stress results to the continuum mechanics solution for a Hertzian fretting contact. The dependence of the wear algorithm stability on the cycle increment of a fretting simulation is also investigated. The effects of friction coefficient, normal force, displacement amplitude, coating thickness, and coating modulus of elasticity on fretting wear are presented.

Towards a Model for Fresh Granular-Paste Systems Based on Discrete Element Method

2010 ◽  
Vol 452-453 ◽  
pp. 569-572 ◽  
Author(s):  
H. Hoornahad ◽  
Eddy A.B. Koenders ◽  
Klaas van Breugel
Keyword(s):  
Discrete Element Method ◽  
Particle System ◽  
Rheological Behaviour ◽  
Discrete Element ◽  
Experimental Results ◽  
Computational Techniques ◽  
Physical Parameters ◽  
Phase System ◽  
Research Approach ◽  
Element Method

Modelling the rheological behaviour of fresh granular-paste systems is the main aim of this study. The research approach is based on a conceptual idea where the paste-interaction system is explicitly modelled by an interactive two phase particle system. As a first approach the cohesive force-displacement interaction was measured for two ideally shaped glass particles bridged by water. Later on, the water was replaced by cement paste and the attraction force acting on the glass particles was measured for increasing inter-particle distances. The results gave a very good impression of the cohesive forces acting on a granular paste system employed by the cementations material in its fresh state. The Discrete Element Method (DEM) is one of the computational techniques that is applied to simulate the granular-paste system. With this method, the fresh granular-paste system is divided into two phases (aggregate/paste) and is modelled by a single-phase or a double-phase system of DEM elements. At the first step, the interaction forces of the particle-paste system are compared with the experimental results achieved from the particle-liquid measurements and expressed as an explicit function based on local geometrical and physical parameters. Modelling and experimental results show good agreement.

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