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Research on the Distribution of Axial Excitation of Positive Pressure Ventilators in the Aspect of Stability Safety of the Load-Bearing Frame

Wieczorek Bartosz, Kaczmarzyk Piotr, Warguła Łukasz, Giedrowicz Marcin, Bąk Damian, Gierz Łukasz, Stambolov Grigor, Kostov Boris

Advances in Science and Technology. Research Journal

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2024

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Vol. 18, no 1

142--154

EN

Positive pressure ventilators are exposed to self-shifting during their operation. The aim of the article was to perform research analysing dynamic excitations resulting from vibrations caused by the operation of the drive system. The tests included four different fans, including one with an electric drive. The tests carried out made it possible to determine the effective RMS R value of vibrations, which is a maximum of 0.970 G, and the direction of the excitation relative to the vertical and horizontal axes. In addition, the values of vibration amplitudes on individual axes of the adopted reference system were determined. In this case, the highest values were measured on the vertical axes for combustion-powered ventilators (vibration value from 20 to 35 m/s2 ) and in the axis along the fan rotor for electric-powered ventilators (vibration value from 1.1 m/s2).

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Modeling and computer heat analysis of the proposed sample for testing hardenability of steel as a simplification of Grossman methods

Gierz Łukasz, Łykowski Wiktor, Fryczyński Ksawery

Journal of KONBiN

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2023

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Vol. 53, iss. 2

17--31

EN

The article presents a calculation model of the proposed sample to test the hardenability of steel to replace a series of samples - one. Previous studies have not included this type of sample shape. The FEM simulation of the sample was also compared with that of a cylindrical cross-sectional sample. The calculations made it possible to verify the initial assumption and provided new opportunities to develop a simplification of real steel hardenability tests of steel. Test results may also allow for the simplification of the designed structure. The work also includes perspectives on the development of the method.

PL

W artykule przedstawiono model obliczeniowy proponowanej próbki do badań hartowności stali celem zastąpienia serii próbek - jedną. Dotychczasowe badania nie obejmowały tego typu kształtu próbki. Symulacja MES próbki została także porównana z próbką cylindryczną na przekroju poprzecznym. Obliczenia pozwoliły na weryfikację przyjętego założenia początkowego i dostarczyły nowych możliwości opracowania uproszczenia badań rzeczywistych hartowności stali. Wyniki badań mogą pozwolić również na uproszczenie projektowanej konstrukcji. Praca zawiera także perspektywy rozwoju metody.

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Numerical and experimental analysis of a centrifugal pump with different rotor geometries

Semkło Łukasz, Gierz Łukasz

Applied Computer Science

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2022

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Vol. 18, no 4

82--95

EN

The paper presents a comparative analysis of the operation of two variants of centrifu-gal pump rotors, a description of the main parameters, and the influence of the blade geometry on the performance characteristics obtained. Rotors have been designed using the arc and point method. Based on the developed 3D CAD models, the rotors were printed using the rapid prototyping method on a 3D printer in FFF (Fused Filament Fabrication) technology, in order to experimentally verify the performance, by placing them on the Armfield FM50 test stand. The analysis part of the CFD includes a fluid flow in Ansys Fluent. The process of creating a flow domain and generating a structural mesh was described, along with the definition of boundary conditions, the definition of physical conditions and the turbulence model. The distribution of pressures and velocities in the meridional sections is shown graphically. The chapter with the experimental analysis contains a description of the measuring stand and the methodology used. The results obtained made it possible to generate the characteristics, making it possible to compare the results received. The results allowed to note the influence of geometry on the behavior of the rotors during operation in the system and to indicate that the arc rotor gets a 7% higher head and 2% higher efficiency than the point method rotor, which gives the basis for its commercial use in industry.

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Calibration of Selected Bulk Biomaterials Parameters for DEM Simulation of Comminution Process. Case Study: Corn and Rice Grains

Kruszelnicka Weronika, Diviš Jan, Hlosta Jakub, Gierz Łukasz, Žurovec David

Advances in Science and Technology. Research Journal

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2022

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Vol. 16, no 5

64--77

EN

Computer simulation of bulk materials behavior, including comminution and fragmentation, using DEM has been growing fast, recently. One of the important tasks to get the reliable simulation results is to provide proper materials and contact parameters, which need to be determined in a series of laboratory experiments. For comminution simulation the additional parameters describing the breakage probability and breakage functions are necessary. While some simulation parameters are available in the literature for brittle materials, valid data are lacking for biomaterials such as cereal, rice or corn grains, especially for comminution parameters. The aim of this study was to present the calibration approach and determination of materials, contact, interaction and breakage parameters for grainy biomaterials. The calibration process was done for rice and corn grains. The calibration approach consists of grains size distribution and shape characterization, friction and restitution coefficient determination, and breakage probability description. Based on the results of the experiments, the models were created in the DEM software. The result was the set of calibrated parameters for rice and corn grains.

5

New Trends in Substrates and Biogas Systems in Poland

Marks Stanisław, Dach Jacek, Fernandez Morales Francisco Jesus, Mazurkiewicz Jakub, Pochwatka Patrycja, Gierz Łukasz

Journal of Ecological Engineering

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2020

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Vol. 21, nr 4

19--25

EN

The amendment to the Polish Renewable Energy Act creates great opportunities for the development of the biogas market in Poland. Years of experience in biogas production in Western Europe and the development of biogas installations in Poland indicate the requirement to look for alternative substrates to those produced from dedicated crop production (mainly maize silage). Feasible solutions include the use of biodegradable waste from agriculture or industry as well as municipal landfill sites. The usage of these substrates in the methane fermentation process offers low cost, high biogas production and the safe management of biowaste. The arguments for using them in biogas installations are persuasive. This article presents new approaches of biogas plant installation solutions which allows for the effective fermentation of biowaste from animal and vegetable production, from the agro-food industry and from municipal waste.