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Operating fouling of process and power equipment
Sénáši, Martin ; Pačíska, Tomáš (referee) ; Jegla, Zdeněk (advisor)
Bachelor thesis describes the issue of fouling of heat exchangers. This thesis briefly describes the fouling mechanisms and introduces the issue of consideration fouling in the design of heat exchangers. From gained information subsequently on simple calculation examples demonstrate using basic calculation methods impact of fouling on process stream. It also describes the impact of fouling on the technical and economic solutions of heat exchangers.
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Flow of coarse-grained particles-water mixture in pipes
Vlasák, Pavel ; Chára, Zdeněk ; Konfršt, Jiří ; Krupička, Jan
The advanced knowledge of coarse-grained slurry flow behavior is important for safe, reliable, and economical design and operation of the pipeline transport. The effect of the mixture velocity, solid concentration, and pipe inclination on the coarse-grained particle – water mixtures flow behavior and pressure drop in the turbulent flow regime was experimentally studied in horizontal, vertical, and inclined pipe of inner diameter D = 100 mm. The respective experimental methods, including radiometric methods for particle concentration distribution in pipe cross-section, were used. Graded basalt gravel was used as a model of solid particles. Concentration distribution in the pipe cross-section and motion of particles along the horizontal pipe invert were also studied. The study revealed that the coarse-grained particle-water mixtures in the horizontal and inclined pipes were significantly stratified. The particles moved principally in a layer close to the pipe invert. However, for higher and moderate flow velocities particle saltation becomes dominant mode of particle conveying and particles moved also in the central and upper part of the pipe cross-section.
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Effect of dense slurry composition on its flow behaviour in horizontal pipe
Vlasák, Pavel ; Chára, Zdeněk
The paper deals with experimental investigation of the dense fine-grained slurries focused on the slurry pressure drops versus average velocity relationship. The content of fine, especially colloidal solid particles evokes a complex non-Newtonian behaviour of the slurry. Flow behaviour of dense slurry depends on particle size distribution, shape, density and chemical composition of the solid phase as well as on concentration of solids and carrier liquid properties. The re-circulation pipe loop with horizontal hydraulically smooth stainless steel pipes was used for measuring the slurry flow parameters. Different slurries containing kaolin, stony dust or sand conveyed in water were measured to document effect of the size distribution and chemical composition on the slurry flow behaviour.
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Flow behaviour of highly concentrated slurries
Vlasák, Pavel ; Chára, Zdeněk
The paper describes results of experimental investigation of the highly concentrated fine-grained slurry. The flow behaviour of the slurry was experimentally investigated for the laminar and turbulent regimes with respect to the effect of solid concentration and flow velocity. The re-circulation pipe loop with smooth stainless steel pipe of the inner diameter D = 17.5 mm was used. Stony dust from Mistrovice quarry (d50 = 8 μm, ρs = 2 701 kg/m3) was used as a solid phase, water was used as a carrier liquid. Volumetric concentration and slurry velocity reached up to 44% and 6 m/s, respectively.
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Porovnání měření zádrže kapaliny ve zkrápěném reaktoru metodou vážení a metodou stopovací látky
Stavárek, Petr ; Staněk, Vladimír ; Jiřičný, Vladimír
This study compares experimental results of liquid holdup in the trickle bed reactor (TBR) measured by two different methods: The tracer method and the column weighting method. These methods were investigated in the trickle bed reactor irrigated by organic liquid. Residence time distribution in liquid phase was measured using a tracer monitored by digital refractometer. Values of the mean residence time necessary for liquid holdup evaluation were obtained from the first statistical moment of the residence time distribution curve. The evaluated liquid holdup data were compared with the liquid holdup data obtained by weighting method on the same laboratory apparatus.
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