Browsing by Subject "particle size distribution"

Now showing 1 - 3 of 3

Access status: Open Access ,
Graphite particle size distribution in nodular cast iron
(2005) Wiencek, Kurt; Skowronek, Tadeusz; Khatemi, Belkheir
A system of non-overlapping random spheres, whose diameters have the Weibull distribution may be used as a model for the graphite in nodule cast iron. For a given material the model probability density function of the Weibull distribution may be determined (as the first approximation) by fitting the PDF of model profile diameters to the one of graphite particle sections. The Weibull distribution may be used as the basis for quantitative metallography of the graphite phase in nodular cast iron.
Access status: Open Access ,
Możliwości poprawy dokładności aproksymacji krzywych składu materiałów uziarnionych
(Wydawnictwa AGH, 2010) Foszcz, Dariusz; Saramak, Daniel; Tumidajski, Tadeusz; Niedoba, Tomasz; Gawenda, Tomasz
The approximation adequacy of particle size distribution curves for various grained materials is very significant in many industrial processing investigations. The authors propose in the paper various approaches to this issue, indicating advantages and disadvantages of classical and non-classical statistical analyzes. On the basis of selected results of particle size distributions of certain grained material, the classical forms of approximated formulas were presented, i.e. GSA, Weibull and log-norm distribution functions. It was indicated that the acceptance of proper maximum particle size is difficult to determine and leads to application of the so-called censored distribution functions. Furthermore, the non-parametrical methods of approximation were applied, such as orthogonal Fourier series and kernel methods. Their application results usually in better adequacy of approximation, but they cannot be the basis for technological interpretation. Furthermore, the approximation by the least squared method was performed with application of weights. The best approximation results were obtained for the logistic distribution function.
Access status: Open Access ,
Wpływ prędkości obrotowej wirnika klasyfikatora przepływowego na osiągi młyna strumieniowo-fluidyzacyjnego
(2006) Zbroński, Daniel; Górecka-Zbrońska, Aleksandra
The necessity of applying materials with high degree of fineness in the contemporary technologies require used to modern technology in mechanical comminution of different substances, which will assure demanded particle size distribution of grinding product. The scientific performances are mostly aimed at the search for new work conditions of industrial grinding devices, which should guarantee parameters and fineness of grinding products and should decrease energy consuming of grinding and improve environmental protection. All the above seems to be met in the researches of granular materials grinding in the high-energetic fluidized bed. The fluidized jet grinding relies on keeping up a turbulent fluidization in the grinding chamber of mill, which is a result of collisions of air counter-fluxes. They make it possible to obtain high-energetic fluidized bed, which in turn ensures an effective comminution of tested granular material. The state of pulsatory fluidization is created in the certain surroundings of an axial zone of the fluidized bed. The state of fountain fluidization is created in the axial zone of the fluidized bed, which is characterised by carryover of grains in the zone of high velocities in the centre core of grinding chamber, then by gravitational falling of coarse fraction near walls and by carrying away of the small fraction by the flowing gas into the separation system. The theoretical basis and experimental results for the fluidized jet grinding of granular materials are presented in the paper. The researches were performed on a laboratory fluidized bed opposed jet mill. The experiment contained grinding tests of selected narrow size fraction of limestone in turbulent fluidized layer conditions. The aim of researches was to explain the influence of the values of rotational speed of flow classifier rotor on the efficiency of mill and the particle size distribution of grinding product. The determined masses and particle size distribution of grinding products make it possible to estimate the quality and the efficiency of the carried out fluidized jet grinding tests.