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Abstract

The main purpose of this article is to verify and validate the mathematical description of the airflow around a wind turbine with vertical axis of rotation, which could be considered as representative for this type of devices. Mathematical modeling of the airflow around wind turbines in particular those with the vertical axis is a problematic matter due to the complex nature of this highly swirled flow. Moreover, it is turbulent flow accompanied by a rotation of the rotor and the dynamic boundary layer separation. In such conditions, the key aspects of the mathematical model are accurate turbulence description, definition of circular motion as well as accompanying effects like centrifugal force or the Coriolis force and parameters of spatial and temporal discretization. The paper presents the impact of the different simulation parameters on the obtained results of the wind turbine simulation. Analysed models have been validated against experimental data published in the literature.
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Authors and Affiliations

Andrzej J. Nowak
Tomasz Krysiński
Zbigniew Buliński
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Abstract

It is commonly known that the cause of serious accidents in underground coal mining is methane. Thus, computational fluid dynamics (CFD) becomes a useful tool to simulate methane dispersion and to evaluate the performance of the ventilation system in order to prevent mine accidents related to methane. In this study, numerical and experimental studies of the methane concentration and air velocity behaviour were carried out. The experiment was conducted in an auxiliary ventilated coal heading in Turkish Hard Coal Enterprises (TTK), which is the most predominant coal producer in Turkey. The simulations were modeled using Fluent-Ansys v.12. Significant correlations were found when experimental values and modeling results were compared with statistical analysis. The CFD modeling of the methane and air velocity in the headings especially uses in auxiliary ventilation systems of places where it is hard to measure or when the measurements made are inadequate.
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Bibliography

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Authors and Affiliations

Gülnaz Daloğlu
1
Mustafa Önder
1
Teresa Parra
2

  1. Eskişehir Osmangazi Üniversitesi Müh. Mim. Fak. Maden Mühendi sliği Bölümü, 26480 Eskişehir, Turkey
  2. University of Valladolid, Department of Energy and Fluid Mechanics, Valladolid, Spain
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Abstract

The paper deals with numerical modelling of carbon dioxide capture by amine solvent from flue gases in post-combustion technology. A complex flow system including a countercurrent two-phase flow in a porous region, chemical reaction and heat transfer is considered to resolve CO2 absorption. In order to approach the hydrodynamics of the process a two-fluid Eulerian model was applied. At the present stage of model development only the first part of the cycle, i.e. CO2 absorption was included. A series of parametric simulations has shown that carbon dioxide capture efficiency is mostly influenced by the ratio of liquid (aqueous amine solution) to gas (flue gases) mass fluxes. Good consistency of numerical results with experimental data acquired at a small-scale laboratory CO2 capture installation (at the Institute for Chemical Processing of Coal, Zabrze, Poland) has proved the reliability of the model.

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Authors and Affiliations

Dariusz Dariusz Asendrych
Paweł Niegodajew
Stanisław Drobniak
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Abstract

FEM (finite element method) is an essential and powerful numerical method that can explicitly optimize the design process of electrical devices. In this paper, the employment of FEM tools such as SolidWorks, COMSOL and ANSYS is proposed in order to aid electrical apparatuses engineering and modeling – those are arc chambers of modular circuit breakers. Procured models of arc chambers have been undergoing simulations concerning heating, electric potential distribution, electric charge velocity and traverse paths. The data acquired has been juxta-positioned against experimental data procured in the Short-Circuit Laboratory, Warsaw University of Technology. The reflection of the theoretical approach was clearly noted in the experimental results. Mutual areas of the modeled element expressed the same physical properties and robustness errors when tested under specific conditions – faithfully reflecting those which were experimented with. Moreover, the physical phenomena essential for electrical engineering could be determined already at the model stage. This procedure proved highly valuable during designing/engineering work in terms of material economy.

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Authors and Affiliations

Ł. Kolimas
S. Łapczyński
M. Szulborski
M. Świetlik
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Abstract

In this paper study results of selected production methods for agricultural biogas are shown and technical and technological aspects of these methods are described for monosubstrate bioreactors. Based on the available literature, modelling of mixing in bioreactors using computational fluid dynamics (CFD) was is demonstrated. As part of the research, the numerical simulation method was used with a tool that contains CFD codes. The model k-ε is used to simulate the mean flow characteristics under turbulent flow conditions. This is a two-equation model that gives a general description of turbulence. The work presents the results of numerical studies that make it possible to understand the characteristics of fluid flow in the adhesive bed used for the production of agricultural biogas. The tests showed that in the core of the adhesive bed there is a flow of 0.19 m∙s –1, while in the outer part of the bed there is a flow in the range 0.01–0.02 m∙s –1. Taking into account the substrate inflow of 0.17 m∙s –1 (in the upper part of the fermentor), it was observed that the Klinkenberg effect for autocyclic movement (from bottom to top) takes place. The novelty in the article is the observation of the dominant flow in the core of the bed and the autocyclic flow in the opposite direction in the peripheral areas of the adhesive bed.
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Authors and Affiliations

Grzegorz Wałowski
1
ORCID: ORCID

  1. Institute of Technology and Life Sciences – National Research Institute, Falenty, al. Hrabska 3, 05-090 Raszyn, Poland

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