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چكيده انگليسي :

Accelerating Lattice Boltzmann Simulation of Multi component Gas Mixture Flow in Packed Bed Using Graphics Processors Seyed Mohammad Amin Safi sm safi@iut ac ir Date of Submission 2011 03 14 Department of Mechanical Engineering Isfahan University of Technology Isfahan 84156 83111 Iran Degree M Sc Language Farsi Supervisor Mahmud Ashrafizaadeh mahmud@cc iut ac ir Abstract The Lattice Boltzmann Method LBM is one of the fledgling approaches to tackle problems in computational fluid dynamics It has been demonstrated to have an outstanding numerical performance especially for multi scale multi component flows and flows in porous media It is originally based on modeling the fluid as distribution functions evolve and stream over a discrete lattice in time and space Due to its highly explicit nature of solution LBM is proved to be a unique candidate for parallelism In addition to the use of multicore CPUs and compute clusters recently many efforts have been made to develop parallel LBM simulations on manycore Graphics Processing Units GPU Recent researches on implementing LBM simulations on GPUs have been very successful showing impressive speedups even on single devices However the resulting computational performance strongly depends on the developers proficiency to harness the maximum efficiency of these new computing architectures One of the very interesting areas to be investigated by the Lattice Boltzmann method is to employ it for simulating gas mixture flows through packed beds Packed beds generally made up of spherical particles have noticeable significance in industrial systems They are being widely used in chromatography operations fuel rods filters containers for chemical substance catalyzors and or fuel particles in solid fuel propulsion systems Besides the complex process of binary mixture diffusion has itself several applications in fluidic systems such as chemically reacting flows gas purification pollutant dispersion and so forth Diffusion of oxygen and nitrogen discussed in the present work is of a crucial importance since these two elements are the major constituents of atmospheric air and their diffusion plays a great role in combustion systems and nitrogen oxygen purification processes Of paramount importance for industry is the flow of oxygen and nitrogen through highly packed beds of spherical particles with adsorption properties which is widely adapted for production of purified oxygen or nitrogen In a recent research by Rastegari and Ashrafizaadeh 2009 LBM was employed to simulate the flow of oxygen and nitrogen mixture in a simple packed bed of spherical particles Although the results are very promising from the physical point of view the simulations suffer from extremely long computational times leading to applying some simplifications to keep the simulation time within affordable bounds In this thesis a 3D lattice Boltzmann flow solver for the binary flow of oxygen and nitrogen mixture has been implemented on GPUs It is highly distinguished from the previous researches since it employs complex highly dense packed beds where the no slip boundary condition is treated accurately on the solid surface of the spherical particles which even doubles the computational cost of the simulations in such media As such and to exploit the maximum computational power of GPUs an optimized algorithm is used and the flow is scaled in a way that the transport equations for both species can be managed in parallel It is shown that using a wide range of modern graphics processors either single or in parallel speedups of more than two orders of magnitudes over single CPUs are achievable bringing the long expensive simulations down to reasonable costs and times Keywords Graphics processing Parallel processing Lattice Boltzmann method Packed beds Gas mixtures

صافي، محمد امين

افزايش سرعت شبيه سازي جريان مخلوط گازها در بستر ذرات فشرده به روش شبكه ي بولتزمن با استفاده از پردازشگرهاي گرافيكي

پردازش موازي , مخلوط گازها