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Mr. Jan Diviš
Ph.D student

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Research Keywords & Expertise

0 DEM
0 Bulk Material
0 DEM simulations
0 Discrete element method (DEM)
0 DEM-FEM coupling approach

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Short Biography

Bulk material handling, storage and processes research.

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Journal article
Published: 23 July 2021 in Sustainability
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The knowledge of a grinder structure, its performance parameters and characteristics of biomaterials breakage are crucial for this research whose aim is to determine the dependencies between performance parameters and comminution indicators. The aim of this study is to investigate the relationships between multi-disc mill performance parameters such as discs angular speed, batch dosing speed and comminution characteristics: power consumption, specific energy consumption, throughput and size reduction ratio. To achieve these goals, an experiment was conducted on a five-disc mill with a special monitoring system. The research program was established, with disc angular speed at different configurations and different batch dosing speeds. The results show that power consumption, specific energy consumption and size reduction ratio depend on the total increase in angular speed of discs SΔω in such a way that an increase in SΔω causes an increase in the abovementioned comminution indicators. In turn, an increase in batch dosing speed W causes an increase in throughput. The fitting curves of comminution indicators in dependence of selected performance parameters are also presented in this study.

ACS Style

Weronika Kruszelnicka; Jakub Hlosta; Jan Diviš; Łukasz Gierz. Study of the Relationships between Multi-Hole, Multi-Disc Mill Performance Parameters and Comminution Indicators. Sustainability 2021, 13, 8260 .

AMA Style

Weronika Kruszelnicka, Jakub Hlosta, Jan Diviš, Łukasz Gierz. Study of the Relationships between Multi-Hole, Multi-Disc Mill Performance Parameters and Comminution Indicators. Sustainability. 2021; 13 (15):8260.

Chicago/Turabian Style

Weronika Kruszelnicka; Jakub Hlosta; Jan Diviš; Łukasz Gierz. 2021. "Study of the Relationships between Multi-Hole, Multi-Disc Mill Performance Parameters and Comminution Indicators." Sustainability 13, no. 15: 8260.

Journal article
Published: 17 June 2021 in Processes
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Cooling is an important process during the production of pellets (as post-treatment). The pellet cooling process significantly impacts the quality of the pellets produced and the systematic use of energy. However, the cooling systems currently in use sometimes encounter technical problems, such as clogging of the perforated grids (sieves), the discharge hopper, or pellet degradation may occur. Therefore, a prototype of a new pellet cooling system using a vibrating feeder was tested. The aim of the study is to present a new variation of pellet cooling system using spiral vibration cooler as a possible solution next to a counterflow cooler. The presented system was tested (critically evaluated and discussed) in two design variants. The first variant consists in cooling by chaotic movement of the pellets. The second is then in combination with the chaotic movement of the pellets together with the action of intense air flow using specially placed air hoses. All tests involved pelletization of rapeseed straw. It was found that both cooling system variants could, realistically, be used. However, the variant with an intense air flow was more energy-intensive, a factor which is, however, offset by the higher quality of the pellets. No negative impact of vibrations to pellets quality was occur. Studies provide insight into new usable technologies that do not reduce the efficiency of the process as a result of grate clogging.

ACS Style

David Žurovec; Lucie Jezerská; Jan Nečas; Jakub Hlosta; Jan Diviš; Jiří Zegzulka. Spiral Vibration Cooler for Continual Cooling of Biomass Pellets. Processes 2021, 9, 1060 .

AMA Style

David Žurovec, Lucie Jezerská, Jan Nečas, Jakub Hlosta, Jan Diviš, Jiří Zegzulka. Spiral Vibration Cooler for Continual Cooling of Biomass Pellets. Processes. 2021; 9 (6):1060.

Chicago/Turabian Style

David Žurovec; Lucie Jezerská; Jan Nečas; Jakub Hlosta; Jan Diviš; Jiří Zegzulka. 2021. "Spiral Vibration Cooler for Continual Cooling of Biomass Pellets." Processes 9, no. 6: 1060.

Journal article
Published: 02 January 2021 in Chemical Engineering Research and Design
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Traditionally, chain conveyors with classic structural carriers are used to transport bulk materials. The research topic of the study was how various geometric carrier shapes could affect, for example, transportation efficiency, wear or the action of forces. For this purpose, 53 alternative geometric shapes were designed and simulated in DEM. The efficiency of the geometric shapes was calculated in terms of the material transport speed, the acting compressive forces, the particulate velocities around the carriers, the wear of the carrier surface, and the resistances in carrier movement. The input parameters of the DEM model of the bulk material and conveyor were experimentally verified by the angle of repose and the validation device of the chain conveyor. Deviations of the DEM validation of material and processes in the conveyor fell in the range 0.29–3.17%. The effect of compressive forces acting on carrier I, II and V was also investigated to determine the efficiency of the processes. Because of the large number of simulations, we designed an optimal simplified model, which was validated with a 2% difference from the original and more computationally demanding model. Based on all the (measured and simulated) values, we determined the optimal design of the carriers by examining the overall efficiency. We found four alternative carrier shapes for the effective area. The article provides a comprehensive overview of the modern methods of analysis and subsequent optimization of contact geometrical surfaces for the purpose of creating prototypes with low economic requirements.

ACS Style

Martin Žídek; Jiří Rozbroj; Lucie Jezerska; Jan Diviš; Jan Nečas; Jiří Zegzulka; Matthias Demmler. Effective use of DEM to design chain conveyor geometry. Chemical Engineering Research and Design 2021, 167, 25 -36.

AMA Style

Martin Žídek, Jiří Rozbroj, Lucie Jezerska, Jan Diviš, Jan Nečas, Jiří Zegzulka, Matthias Demmler. Effective use of DEM to design chain conveyor geometry. Chemical Engineering Research and Design. 2021; 167 ():25-36.

Chicago/Turabian Style

Martin Žídek; Jiří Rozbroj; Lucie Jezerska; Jan Diviš; Jan Nečas; Jiří Zegzulka; Matthias Demmler. 2021. "Effective use of DEM to design chain conveyor geometry." Chemical Engineering Research and Design 167, no. : 25-36.

Journal article
Published: 01 September 2018 in Advances in Science and Technology Research Journal
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This article addresses the optimization of a dosing tank using a spiral harmonic motion. The dosing tank is used for the short-term storage of cohesive sand, which is then released into a tubular mold. Originally, a solution based on the principle of wiping the material using rotary blades and...

ACS Style

David Zurovec; Jan Necas; Jan Diviš; Jakub Hlosta; Jiri Zegzulka; Katerina Urbanova. OPTIMIZATION OF DOSING TANK EMPTYING USING SPIRAL VIBRATION. Advances in Science and Technology Research Journal 2018, 12, 143 -149.

AMA Style

David Zurovec, Jan Necas, Jan Diviš, Jakub Hlosta, Jiri Zegzulka, Katerina Urbanova. OPTIMIZATION OF DOSING TANK EMPTYING USING SPIRAL VIBRATION. Advances in Science and Technology Research Journal. 2018; 12 (3):143-149.

Chicago/Turabian Style

David Zurovec; Jan Necas; Jan Diviš; Jakub Hlosta; Jiri Zegzulka; Katerina Urbanova. 2018. "OPTIMIZATION OF DOSING TANK EMPTYING USING SPIRAL VIBRATION." Advances in Science and Technology Research Journal 12, no. 3: 143-149.