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Modelling of particle size distribution of the monodispersion silica's free jet milling product |
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Modelling of particle size distribution of the monodispersion silica's free jet milling product Authors: E. Mielczarek, D. Urbaniak
In the paper a modified model of particle size distribution of the monodispersion fragile material's free jet milling product is presented. On the basis Maxwell-Boltzmann law and thermodynamic comminution theory the algorithm of analytical evaluation of arbitrary particle-class mass fraction in the whole product of free comminution is worked out. The classic Maxwell-Boltzmann law relates to distribution kinetic energy of molecules of ideal gas. In the case of solid there is not kinetic energy of molecules. So it is assumed, that total internal energy is equal to the intermolecular bond energy with potential character. Value of this energy depends on particle size. For small particles the energy level is figher than for. big one. Summary masses mesh through i-th sieve depends on value of difference energy of i-th level and energy of basic level. The basic energy level corresponds to the smallest energy level and it characterises the intermolecular bond energy in the biggest particles. Appearing in the function size of biggest particles is constants for fed material. Value of this size depends on some mechanical properties of substance, on specific surface values of fed material, on specific comminution energy and specific border energy. Connecting of above function enebles numerical prediction particles size distribution of monodispersion fed material free jet comminution product. Coefficient improvements specific surface, because this greatness was counting for plain spherical particles. The determined relationships were verified experimentally with using monodispersion samples of material within range 400-800 um and 100-320 um. The sorted material samples were single-pass comminuted using the jet mill of the pumps opposite to each other. After tests selected samples of milling products were analysed on a sieve set and infrared particle sizer. Than on the basic of worked out model the numerical calculations of particle size distributions of monoclass sand jet comminution products were calculated. The computations were performed for the same values of kinetic energy and specific surface of fed sand as in the experiment. In this paper graphics and tables comparison between tests results and numerical simulation results are presented.
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2011