National Repository of Grey Literature 97 records found  beginprevious88 - 97  jump to record: Search took 0.00 seconds. 
Sedimentation of heterogeneous ash slurry : fly and bottom ash Porici
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří ; Hoření, Bohumír ; Mutl, Silvestr
Settling velocities of heterogeneous ash-water mixture with fly/bottom ash ratio 10:0; 95:5;9:1;8:2 and 7:3 were measured using the batch sedimentation method. The effect of bottom ash content is significant, settling velocity increases with growing of coarse particle ratio up to total concentration about cv = 20%, then for higher cv and coarse particle ratio higher than 2:8 the settling velocity decreases with growing total concentration.
Investigation of flow behaviour of homogeneous and heterogeneous ash slurries: fly and bottom ash Porici
Chára, Zdeněk ; Vlasák, Pavel ; Konfršt, Jiří
The flow behaviour of fly ash and bottom ash from fluidic combustion slurries was experimentally investigated for laminar, transitional and turbulent regimes with respect to the effect of solid concentration, particle size distribution and time and intensity of shearing in smooth stainless steel pipes of inner diameter of 26.8 and 36 mm. Volumetric concentration ranges from 20 to 32 %, slurry velocity reach value up to 5 m/s. It was demonstrated that turbulent shearing or addition of bottom ash results in the significant decrease of the apparent viscosity; also laminar/turbulent transition region was reached for lower flow velocity.
Vliv velikosti částic a průměru potrubí na tokový odpor při proudění hydrosměsí
Matoušek, V. ; Chára, Zdeněk ; Vlasák, Pavel
The sizes of pipe and particle are factors that have great influence on the distribution of particles within the mixture flow and thus on the pressure drops over the length of the pipeline transporting the mixture. The paper evaluates the effects of the sizes on the basis of laboratory measurements of various sorts of sand in pipes of two very different diameters: 26.8 mm and 150 mm
Turbulentní tokové charakteristiky nenewtonovských jemnozrnných suspenzí při proudění v potrubí
El-Nahhas, K. ; Vlasák, Pavel
The prediction of the turbulent flow pressure losses for non-Newtonian suspensions is still one of the difficult theoretical and practical problems. The difficulty results from the fact that the turbulent flow behaviour could be found independent on the rheological characteristics determined experimentally form laminar data. The aim of the paper is experimentally investigate the turbulent flow behaviour of non-Newtonian fine-grained suspensions flowing in pipes
Vliv zrnitostního rozdělení na tokové chování koncentrovaných hydrosměsí obsahujících fluidní popely
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří
Most knowledge on the flow behaviour of highly concentrated slurries has been concerned with the slurries containing either fine-grained particles creating homogeneous, often non-Newtonian slurry or coarse-grained particles creating heterogeneous slurry with settling tendencies. The paper deals with the effect of slurry composition and volumetric concentration on flow behaviour of slurries containing colloidal, clay, dust and also coarse-grained particles
Numerický 3D model kolize pevné částice s drsným dnem kanálu
Lukerchenko, Nikolay ; Chára, Zdeněk ; Vlasák, Pavel
The paper deals with 3D numerical model of the random process of rotating spherical particle-bed impact and rebound for saltation movement of a particle in channels with rough bed. The collision height and the contact point are defined as random variables of the collision process. The collision height depends on bed roughness. The contact point position depends on the irection of the particle velocity vector before the collision
Použití "rovnic mělké vody" na proudění nenewtonských suspenzí
Hoření, Bohumír ; Chára, Zdeněk ; Vlasák, Pavel
The paper presents an attempt to use shallow water equations to solve a flow of non-Newtonian suspensions. Saint-Vennant set of equations of incompressible free surface flow in thin layers (frequently referred as "shallow water equations") forms a baseline for theoretical solution. The original set of equations established for Newtonian fluids is modified to solve also flow of non-Newtonian fluids with arbitrary rheological behaviour
Transport hrubých částic v nenewtonovských suspenzích
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří
The paper deals with flow behaviour of slurries containing colloidal, clay, dust and also coarse-grained particles. The slurry flow behaviour changes form Newtonian to non-Newtonian in dependence on the solid phase concentration and composition, especially on the contents of colloidal particles. Flow behaviour of fluidic fly and bottom ash slurries, clay and sand slurries was experimentally investigated with respect to the solids composition, volumetric concentrationa and slurry velocity. The re-circulation pipe loop with smooth stainless steel pipes of the inner diameters D = 17.5, 26.8 and 36 mm was used for measuring the slurry flow parameters. Also the effect of time and intensity of shearing was studied for time dependent fluidic ash slurries
Experimentální výzkum odporu rotačně se pohybující kulové částice
Lukerchenko, Nikolay ; Kvurt, Y. ; Chára, Zdeněk ; Vlasák, Pavel
Saltatory solid particles conveyed by fluid impact a channel bed from time to time. As a result of the collision the particles receive angular velocity, which gradually decreases with time. For numerical simulation of saltation it is necessary to know values of the drag rotation coefficient. In this paper experimental results of the rotating spherical particles moving in water are described. The rubber spherical balls with density near that of water were used; each of them was speeded up in a special chute that ensured that the particle rotated in a given plane. Values of the drag coefficient of the rotating spherical particle were determined in a dependence on rotation particle Reynolds number
Vývoj irského hospodářství od vstupu do EHS po současnost
Vlasák, Pavel ; Štěrbová, Ludmila (advisor) ; Černá, Iveta (referee)
Práce popisuje vývoj irské ekonomiky od vstupu do EHS po současnost. První část zahrnuje stručný popis země a její historie, zmíněn je taktéž i politický systém. Makroekonomický vývoj, včetně fiskální a monetární politiky od roku 1973 po současnost je analyzován v druhé části. Poslední část se zabývá některými aspekty irské ekonomiky, zejména přímými zahraničními investicemi a dotacemi ze strany EU.

National Repository of Grey Literature : 97 records found   beginprevious88 - 97  jump to record:
See also: similar author names
3 Vlasák, Patrik
14 Vlasák, Petr
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