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Abstract

The article presents a numerical model of a U-ventilated longwall, taking into account detailed elements such as arch yielding support, roof supports and shearer. What distinguishes it from previous models is the mapping of adjacent goafs. This model considers the current state of knowledge regarding spatial height distribution, porosity and permeability of goafs. Airflow calculations were carried out using the selected turbulence models to select appropriate numerical methods for the model. Obtained results show possibilities of conducting extensive numerical calculations for the flow problems in the mine environment, taking into account more complex descriptions and the interpretation of the calculation results carried out with simpler models.
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Bibliography

[1] Ansys Inc, Ansys Fluent Theory Guide. Ansys Inc (2019).
[2] M. Baścik, 3D laser scanning in underground mines – practical experience. School of Underground Mining 2013. The Mineral And Energy Economy Research Institute of Polish Academy of Sciences (2013).
[3] P.Y. Chou, On velocity correlations and the solutions of the equations of turbulent fluctuations. Quarterely of Applied Mathematics (1945).
[4] N .S. Dhamakar, G.A. Blasdell, A.S. Lyrintzis, An Overview of Turbulent Inflow Boundary Conditions for large Eddy Simulations. Proc of the 22 nr AIAA Computational Fluid Dynamics Conference AIAA Paper (2015).
[5] W. Dziurzyński, Prognozowanie procesu przewietrzania kopalni głębinowej w warunkach pożaru podziemnego. Instytut Gospodarki Surowcami Mineralnymi i Energią PAN, Kraków (1998).
[6] J. Janus, PhD thesis, Modelling of flow phenomena in mine drifts using the results of laser scanning. Strata Mechanics Research Institute of Polish Academy of Sciences (2018).
[7] J. Janus, The Application of laser scanning in the process of constructing a mine drift numerical model. 24th World Mining Congress PROCEEDINGS – Underground Mining, Brazilian Mining Association, Rio de Janeiro (2016).
[8] J. Janus, The application of laser scanning in the process of construction a mine drift numerical model. Transactions of the Strata Mechanics Research Institute 18, 3 (2016).
[9] J. Janus, Assessment of the possibilities of using laser scanning for numerical models constructions. Transactions of the Strata Mechanics Research Institute 17, (1-2) (2015).
[10] J. Janus, Wpływ zapory przeciwwybuchowej wodnej na pole prędkości i warunki przewietrzania wyrobiska kopalnianego. Archives of Mining Sciences, Seria: Monografia, Nr 19 (2019).
[11] J. Janus, J. Krawczyk, An Analysis of the Mixing of Air and Methane in the Stream Produced by the Mine Injector Station – Present Results of Measurements and Modeling. The Australian Mine Ventilation Conference 2013, The Australian Institute of Mining and Metallurgy (2013).
[12] J. Janus, J. Krawczyk, Measurement and Simulation of Flow in a Section of a Mine Gallery. Energies 14, 4894 (2021). DOI: https://doi.org/10.24425/ather.2019.128295
[13] J. Janus, J. Krawczyk, The numerical simulation of a sudden inflow of methane into the end segment of a longwall with Y – type ventilation system. Archives of Mining Sciences 59, (4) (2014).
[14] A. Kidybiński, Podstawy geotechniki kopalnianej. Wydawnictwo Śląsk, Katowice (1982).
[15] J. Krawczyk, J. Janus, An example of defining boundary conditions for a flow in a mine gallery. Abstract in the XXIII Fluid Mechanics Conference Materials, Zawiercie (2018).
[16] J. Krawczyk, J. Janus, Velocity field in the area of artificially generated barrier on the mine drift floor. Przegląd Górniczy 71, (11) (2015).
[17] J. Krawczyk, Single and multiple-dimensional models of unsteady air and gas flows in underground mines. Archives of Mining Sciences, Seria: Monografia, No 2 (2007).
[18] F. Menter, Turbulence Modeling for Engineering Flows. ANSYS 2012 Inc. (2012). [19] F. Menter, Best Practice – Scale-Resolving Simulations in ANSYS CFD – Application Brief Version 2.0 (2015).
[20] J. Pokorný, L. Brumarová, P. Kučera, J. Martinka, A. Thomitzek, P. Zapletal, The effect of Air Flow Rate on Smoke Stratification in Longitudinal Tunnel Ventilation. Acta Montanistica Slovaca 24, (3) (2019).
[21] T. Ren, R. Balusu, C. Claassen, Computational Fluid Dynamics Modelling of Gas Flow Dynamics in Large Longwall Goaf Areas. 35th APCOM Symposium (2011).
[22] P. Skotniczny, Three-Dimensional Numerical Simulation of the Mass Exchange Between Longwall Headings and Goafs, in the Presence of Methane Drainage in A U-Type Ventilated Longwall. Archives of Mining Sciences 58, (3) (2013).
[23] V. Sokoła-Szewioła, J. Wiatr, Application of laser scanning method for the elaboration of digital spatial representation of the shape of underground mining excavation. Przegląd Górniczy 8 (2013).
[24] J. Szlązak, PhD thesis, Wpływ uszczelniania chodników przyścianowych na przepływ powietrza przez zroby. AGH Kraków (1980).
[25] N. Szlązak, J. Szlązak, Wentylacja wyrobisk ścianowych w kopalniach węgla kamiennego, w warunkach zagrożenia metanowego i pożarowego. Górnictwo i Geologia (2) (2019).
[26] K. Wierzbiński, Wpływ geometrii chodnika wentylacyjnego i sposobu jego likwidacji na rozkład stężenia metanu w rejonie wylotu ze ściany przewietrzanej sposobem U w świetle obliczeń numerycznych CFD. Zeszyt Naukowy Instytutu Gospodarki Surowcami Mineralnymi i Energią Polskiej Akademii Nauk, No 94 (2016).
[27] M.A. Wala, S. Vytla, C.D. Taylor, G. Huang, Mine face ventilation: a comparison of CFD results against benchmark experiments for the CFD code validation. Mining Engineering (2007).
[28] D.M. Worrall, E.W. Wachel, U. Ozbay, D.R. Munoz, J.W. Grubb, Computational fluid dynamic modeling of sealed longwall gob in underground coal mine – A progress report. 14th United States/North American Mine Ventilation Symposium, Calizaya & Nelson (2012).
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Authors and Affiliations

Jakub Janus
1
ORCID: ORCID

  1. Strata Mechanics Research Institute, 27 Reymonta Str., 30-059 Kraków, Poland
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Abstract

The analysis of natural hazards, including gas-geodynamic phenomena, requires study of the basic physical processes that take place at each stage of an event. This paper focuses on analysing the transport of fragmented rock material during rock and gas outbursts. Our theoretical considerations and experiments have allowed us to specify and verify the significant forces acting on fragmented rock during its transport, thus determining the speed of grains of each grain class in the stream of expanding gas. The above study may serve as a preface to a wide-ranging quantitative and qualitative energy analysis of the movement of material ejected during Gas-geodynamic phenomena.
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Authors and Affiliations

Katarzyna Kozieł
1
ORCID: ORCID
Jakub Janus
1
ORCID: ORCID

  1. Strata Mechanics Research Institute of the Polish Academy of Science, 27 Reymonta Str., 30-059 Kraków, Poland
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Abstract

For underground mine workings, the shape of the computational domain may be difficult to define. Historically, the geometry models of mine drifts were not accurate representations of the object but rather a simplified approximation. To fully understand a phenomenon and save time on computations, simplification is often required. Nevertheless, in some situations, a detailed depiction of the geometry of the object may be necessary to obtain adequate simulation results. Laser Scanning enables the generation of 3D digital models with precision beyond the needs of applicable CFD models. Images composed of millions of points must be processed to obtain geometry suitable for computational mesh generation. A section of an underground mine excavation has been selected as an example of such transformation. Defining appropriate boundary conditions, especially the inlet velocity profile, is a challenging issue. Difficult environmental conditions in underground workings exclude the application of the most efficient and precise methods of velocity field measurements. Two attempts to define the inlet velocity profile have been compared. The first one used a sequence of simulations starting from a flat profile of a magnitude equal to the average velocity. The second one was based on the sixteen-point simultaneous velocity measurement, which gave consistency with measurement results within the range of applied velocity measurement method uncertainty. The article introduces a novel methodology that allows for more accurate replication of the mine excavation under study and the attainment of an appropriate inlet velocity profile, validated by a satisfactory correspondence between simulation outcomes and field measurements. The method involves analysing laser-scanned data of a mine excavation, conducting multi-point velocity measurements at specific cross-sections of the excavation that are unique to mining conditions, and utilising the k-ω SST turbulence model that has been validated for similar ventilation problems in mines.
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Authors and Affiliations

Jakub Janus
1
ORCID: ORCID
Jerzy Krawczyk
1
ORCID: ORCID

  1. Strata Mechanics Research Institutes of Polish Academy of Science, 27 Reymonta Str., 30-059 Kraków, Poland
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Abstract

Work on increasing the efficiency of heat exchangers used in car air conditioning systems may lead to a partial change in the construction of refrigeration systems. One of such changes is the use of smaller gas coolers, which directly translates into a reduction in the production costs of the entire system. The article presents the use of computational fluid dynamics methods to simulate the impact of changing the shape of an internal heat exchanger on the cooling efficiency with R744 as the refrigerant. Internal heat exchangers with different geometry of the outer channels were subjected to numerical analysis. The obtained results of calculations show temperature changes in inner and outer channels on the length of the heat exchanger.

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Authors and Affiliations

Jakub Janus
ORCID: ORCID
Przemysław Jan Skotniczy
Maria Richert

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