Lattice-Boltzmann code

A demonstration of this approach has been reported to evaluate the ability of a lattice-Boltzmann code to predict both spatially resolved flow fields and MR propagators characterizing flow through random packings of spheres (model fixed beds) for flows defined by Peclet (Pe) and Reynolds numbers in the range 182 < Pc <3 50 and 0.4 < Re <0.77 (85). Excellent agreement was found between the numerical predictions and experimental measurements. Current interest in this field addresses the validation and development of numerical codes predicting flows at Reynolds numbers more appropriate to real catalytic reactors. 

Van de Graff et al. [94] used a lattice Boltzmann code to predict the effect of velocity and interfacial tension on the formation of droplets in a T-shaped microchannel. Very good agreement between the simulations and experimental data was obtained and the model was used to show that a combination of the capillary number and the flow rate of the fluid to be dispersed control the droplet size. 

There is growing use of lattice Boltzmann and other partide-based codes that can circumvent many of the problems of traditional Navier-Stokes-based solvers. However, their use requires spedalist knowledge and they are not available... 

Commercial codes, e.g. PowerFLOW, which use lattice-based approaches are available, and this particular code was used in the present work. Based on discrete forms of the kinetic theory equations, this code employs an approach that is an extension of lattice gas and lattice Boltzmann methods in which particles exist at discrete locations in space, and are allowed to move in given directions at particular speeds over discrete time intervals. The particles reside on a cubic lattice composed of voxels, and move from one voxel to another at each time step. Solid surfaces are accommodated through the use of surface elements, and arbitrary surface shapes can be represented. Particle advection, and particle-particle and particle-surface interactions, are all considered at a microscopic level to simulate fluid behaviour in a way which ensures conservation of mass, momentum and energy, and which recovers solutions of the continuum flow... 

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