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    Wyświetlanie 1-8 z 8
    Tytuł:
    The analysis of the relations between porosity and tortuosity in granular beds
    Autorzy:
    Sobieski, W.
    Lipiński, S.
    Powiązania:
    https://bibliotekanauki.pl/articles/950448.pdf
    Data publikacji:
    2017
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    porous media
    granular beds
    porosity
    tortuosity
    Opis:
    In the paper, functions describing different porosity-tortuosity relations were collected, and then the tortuosity values were calculated for a one granular bed consisting of spherical particles with normal distribution of diameters. Information about the bed porosity and particle sizes was obtained from measurements conducted for an artificial granular bed, consisting of glass marbles. The results of calculations were compared with the results of two other methods of tortuosity determination, performed for the same case (details are not described in this paper): the first of them uses the Path Tracking Method, the second one - information about the velocity components in a creeping flow (the Lattice-Boltzmann Method was applied to obtain the velocity field in the flow). The main aim of our article was to test whether the functions linking tortuosity with porosity, which are available in the literature, give similar results as the methods described above. To achieve this aim, the relative errors between results of calculations for the collected formulas and values from the both previous mentioned methods were calculated.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2017, 20(1); 75-85
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Sensitivity analysis of Kozeny-Carman and Ergun equations
    Autorzy:
    Sobieski, W.
    Zhang, Q.
    Powiązania:
    https://bibliotekanauki.pl/articles/297987.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    porous media
    Kozeny-Carman
    Ergun
    porosity
    tortuosity
    Opis:
    In the article a sensitivity analysis of linear and nonlinear terms in the Kozeny-Carman and Ergun equations was shown. In the first case the impact of the porosity, tortuosity, specific surface of the porous body and the model constant was investigated. In the second case the porosity, the particle diameter and the sphericity function were taken into account. To express the model sensitivity by numbers, an earlier developed method was used. In this way the order and the importance of the impact of individual parameters was determined. The motivations to create this article were questions, which occurred during developing a novel investigation method, linking the Discrete Element Method and the CFD techniques. The first aim was to predict what will happen, if individual parameters will be set with an error: which data should be set as accurately as possible and which data are not very important for the result value. The second intention was to state which of parameters used in porous media investigations should be expressed by functions and which by constant values. The article may be treated as set of pointers helping in using of Kozeny-Carman and Ergun laws or as an example of research methodology based on the sensitivity analysis.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(3); 235-248
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Influence of granular bed parameters on emulsion flow and elution process of oil-in-water emulsion
    Autorzy:
    Błaszczyk, M.
    Pacholski, P.
    Przybysz, Ł.
    Sęk, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/298006.pdf
    Data publikacji:
    2016
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    porous media
    oil-in-water emulsion
    elution
    Opis:
    Emulsion flow through porous structure is used in many processes in the field of chemical engineering. Good examples of practical applications are Enhanced Oil Recovery (EOR) techniques, soil remediation and treatment of oily wastewater. The emulsion transport in through porous media is not easy to describe, due to rheological behavior of emulsions and porous structure properties. In case of emulsified system flow through porous bed it is possible to observe the retention of oil on porous structure, and reduction of permeability of bed. In the presented study, we tried to investigate the influence of porous bed parameters on oil-in-water emulsion behavior during its flow and elution from porous structure. In experiments we used porous beds with varied particle size range and with different lengths. We measured pressure drop and related permeability changes in time. The turbidimetric and microscopic analysis that we conducted allowed us to check how concentration of emulsion changed during its flow and elution from porous structure.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2016, 19(4); 325-337
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Modification of the PathFinder algorithm for calculating granular beds with various particle size distributions
    Autorzy:
    Dudda, W.
    Sobieski, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/297908.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    PathFinder code
    porous media
    granular beds
    tortuosity
    Opis:
    This paper discusses a new approach to analyzing fluid flow through a granular bed. The analysis involves the determination of a set of geometric parameters characterizing a granular bed based on information about the location and diameter of all bed particles. The above task has been achieved with the use of the PathFinder numeric code developed by the authors. The study proposes a new algorithm for calculating the parameters of granular beds composed of spherical particles with various diameters in the PathFinder program. The algorithm has been verified with the use of independent tools and implemented in the new version of the PathFinder code. The modified algorithm’s effect on flow path tortuosity has been analyzed. Path length is used to determine tortuosity, a key parameter of pore geometry that is difficult to calculate. Comparative calculations were performed in a granular bed generated by the Discrete Element Method in the PFC3D program.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(2); 135-148
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Darcy’s and Forchheimer’s laws in practice. Part 1. The experiment
    Autorzy:
    Sobieski, W.
    Trykozko, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/297795.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    Darcy’s law
    Forchheimer's law
    Forchheimer Plot Method
    porous media
    permeability
    Opis:
    The aim of this study is to derive flow parameters, which are permeability and Forchheimer coefficient, based on experimentally measured flow rates and pressure drops. When flow rates used in measurements exceed the limits of linear Darcy’s flow regime we discuss what needs to be taken into account while processing the measurements. The study consists of two parts. In this part we briefly recall Darcy’s and Forchheimer’s laws and address the issue of detecting transition between ranges of their applicability. Then we describe the experiment and discuss 8 different ways to process measurement data, four for Darcy’s, and four for Forchheimer’s models. The main topic of the second part is to provide recommendations for the best ways to process data, so that the results obtained with numerical models are in the best agreement with the experimental data. The results shown in the two papers belong to a larger work devoted to modeling fluid flows through porous media, with a special interest in granular beds.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(4); 321-335
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Darcy’s and Forchheimer’s laws in practice. Part 2. The numerical model
    Autorzy:
    Sobieski, W.
    Trykozko, A.
    Powiązania:
    https://bibliotekanauki.pl/articles/297860.pdf
    Data publikacji:
    2014
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    Darcy’s law
    Forchheimer's law
    Forchheimer Plot Method
    porous media
    permeability
    Opis:
    Our study is based on a column experiment of water flow through a porous granular bed. In Part 1 we propose eight methods to derive parameters of flow models based on measurement data. These parameters are permeability and Forchheimer coefficient for Darcy’s and Forchheimer’s laws. The approach presented in this part uses two numerical models to perform simulations of flow. One model is based on the Finite Element Method implemented in the authors’ code. The second model, which is ANSYS/Fluent package, uses the Finite Volume Method. Results of numerical computations are compared with experimental data that allows determination of the best method of parameter evaluation (in which the error was less than 3% over the whole range of filtration velocities). The problem of identification of ranges of applicability of the Darcy’s and Forchheimer’s laws is also addressed. In the conclusions, a set of guidelines is given, which should facilitate planning a similar experiment and its computational processing.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2014, 17(4); 337-350
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Fuzzy logic approach in the analysis of heat transfer in a porous sorbent bed of the adsorption chiller
    Autorzy:
    Grabowska, K.
    Krzywański, J.
    Sztekler, K.
    Kalawa, W.
    Nowak, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/297943.pdf
    Data publikacji:
    2018
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    adsorption chiller
    porous media
    fuzzy logic
    thermal conductivity
    coated adsorption bed
    Opis:
    Thermal conductivity in the boundary layer of heat exchange surface is the crucial parameter of adsorption process efficiency which occurs in the adsorption bed. In order to improve heat transfer conditions in the adsorption chiller, novel constructions of adsorption beds are currently investigated. The porous structure of the sorbent layer causes low thermal conductivity in the adsorption bed. One of the methods to improve heat transfer conditions is a modification of porous media bed structure with glue which is characterized with higher thermal conductivity. The optimum parameters of sorbents and glues to build the novel coated construction, in terms of improving the chiller Coefficient of Performance (COP) were defined in (Grabowska et al. 2018a). The paper implements fuzzy logic approach for predicting thermal conductivity of modified porous media layers. The developed model allows determination of the sorbent layer thermal conductivity based on various input parameters: arithmetic average of particle distribution d, density ρ and thermal diffusivity k. The data from empirical research was used to build up the model by fuzzy logic methods.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2018, 21(4); 281-290
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Time consumption in calculations of hydraulic and geometrical tortuosity in granular beds
    Autorzy:
    Sobieski, Wojciech
    Raoof, Amir
    Zech, Alraune
    Powiązania:
    https://bibliotekanauki.pl/articles/950077.pdf
    Data publikacji:
    2020
    Wydawca:
    Uniwersytet Warmińsko-Mazurski w Olsztynie
    Tematy:
    granular porous media
    geometric tortuosity
    hydraulic tortuosity
    Path Tracking Method
    Discrete Element Method
    Lattice Boltzmann Method
    Opis:
    Tortuosity is one of the most elusive parameters of porous media due to its subjective estimation. Here, we compare two approaches for obtaining the tortuosity in granular porous media to investigate their capabilities and limitations. First, we determine the hydraulic tortuosity based on the calculated components of the velocity field obtained from flow simulations using the Lattice Boltzmann Method (LBM). Second, we directly determine the geometric tortuosity by making use of the Path Tracking Method (PTM) which only requires the geometric properties of the porous medium. In both cases, we apply the same geometrical structure which is a virtually generated 3D granular bed using the discrete element method consisting of 50 particles. Our results show that the direct PTM is much faster and more precise than the indirect approach based on the calculated velocity field. Therefore, PTM may provide a tool for calculating tortuosity for large 3D granular systems where indirect methods are limited due to the required computational power and time. While LBM considers various routes across the porous media implicitly, PTM identifies them explicitly. As a result, PTM requires a statistical post-processing. As an advantage, this can provide further information than just domain scale average values.
    Źródło:
    Technical Sciences / University of Warmia and Mazury in Olsztyn; 2020, 23(1); 25-51
    1505-4675
    2083-4527
    Pojawia się w:
    Technical Sciences / University of Warmia and Mazury in Olsztyn
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-8 z 8

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