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Binary Nucleation H2SO4 in a Laminar Co-Flow Tube, Binary Nucleation H2SO4 in a Laminar Co-Flow Tube
Trávníčková, Tereza ; Havlica, Jaromír ; Škrabalová, Lenka ; Hrubý, Jan ; Ždímal, Vladimír
Nucleation of sulfuric acid with water is one of key processes during new particle formation in the atmosphere. Despite the fact that first experiments dealing with binary nucleation of H2SO4-H2O appeared in the seventies of the 20th century, its mechanism is still not fully understood. This is largely due to difficulties in specifying atmospheric conditions under which nucleation occurs and complexity of laboratory experiments. In studies on binary nucleation using flow chambers with turbulent mixing of components (most often used technique), the experimentalists face two major problems. They have to determine the position of the nucleation zone as accurately as possible, and, at the same time, define acid vapor concentration in the nucleation zone. In this paper we present a Laminar Co-Flow Tube a device for measuring of binary nucleation which overcomes both of these problems. First results on nucleaction rates obtained on this type of device show that it is a useful tool for studying binary nucleation.
Fulltext: content.csg -  PDF
Plný tet: SKMBT_C22015102910280 - PDF
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The Effects of Agitated Beds Homogenization on Stirrer Geometry and Bed Depth via DEM
Kohout, M. ; Trávníčková, Tereza ; Havlica, Jaromír
In this contribution open source DEM particle simulation software LIGGGHTS was studied and tested. Collision forces are there modelled by the softsphere approach with the Hertzian collision model. As an application we studied agitated particle beds (packed from glass spherical particles of two colours – packed vertically and horizontally) mixed by different types of agitators. Dependence of degree of homogenization on particle diameter, particle properties (Young’s modulus), and on geometrical aspects (bed depth, agitator position, etc.) will be also discussed.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014090110404 - PDF
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Granular Dynamics of the Mixing Processes for Different RPM Using DEM
Jirounková, K. ; Havlica, Jaromír ; Kohout, M.
This paper emphasizes on the computer simulations of the granular materials via Discrete Element Method (DEM) by using open-source software LIGGGHTS. The examined process was mixing of two granular materials distinct by colour. The different initial conditions have led to finding the best way of homogenization, but it also shows the new perspective of noticing the process as a system of inseparable processes linked to each other.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014090110403 - PDF
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Mathematical Modeling of the Movement of the Solid Phase using Software LIGGGHTS
Jirounková, K. ; Havlica, Jaromír ; Kohout, M.
The main aim of this work was using the open-source software LIGGGHTS for desribing the solid phase behaviour. This software package is based on the discrete element method (DEM), where every particle consists of an asseblies of spheric particles. Each of these particles is linked to the others and their move is characterised by their ceter of gravity. There were described the basic examples by using softwarepackage LIGGGHTS; such as creating the granular layer and its mixing by using different types of the stirrer.
Fulltext: content.csg - PDF
Plný tet: SKMBT_C22014022814090 - PDF
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