Determination of the normal spring stiffness coefficient in the linear spring–dashpot contact model of discrete element method

• Published in: Powder technology Vol. 246; pp. 707 - 722
• Main Authors: Navarro, Helio A., de Souza Braun, Meire P.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.09.2013; Elsevier
• Subjects: Applied sciences; Chemical engineering; Contact force; Discrete element method (DEM); Exact sciences and technology; Fluidization; fluidized beds; Hydrodynamics of contact apparatus; linear models; Miscellaneous; Multiphase flows; nonlinear models; Solid-solid systems; Spring stiffness coefficient; Spring–dashpot models; Discrete element method (DEM); Multiphase flows; Contact force; Spring stiffness coefficient; Spring–dashpot models; Multiphase flow; Fluidization; Discrete element method; Modeling; Linear model; Bubbling; Non linear model; Spring―dashpot models; Particle interaction; Numerical simulation; Stiffness; Fluidized bed
• ISSN: 0032-5910; 1873-328X
• DOI: 10.1016/j.powtec.2013.05.049

The discrete element method is a method for simulation of a particle system. For the “soft-sphere” mechanism of particle interactions, there are several models for normal contact forces, namely linear spring–dashpot, and non-linear damped Hertzian spring–dashpot, among others. The focus of this paper is to determine the normal spring stiffness coefficient of the linear model through the numerical solution for the overlap between particles in non-linear models. The linear spring stiffness is determined using equivalence between the linear and the nonlinear models. Using the MFIX computational code, the proposed approach is applied in the numerical simulations of two problems: single freely falling particle and bubbling fluidized bed. A method based on mean dimensionless overlap is suggested as an initial estimate to determine the normal spring stiffness coefficient. Other possible methods for computing the stiffness coefficient are also discussed in this work, e.g., maximum dimensionless overlap and dimensionless contact duration. [Display omitted] •Method for determination of the spring stiffness coefficient of the linear model•Analytical derivation of the linear spring–dashpot model•Description of two non-linear damped Hertzian spring–dashpot models•Non-dimensional expressions, tables and graphics for the models•MFIX simulations of two problems