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Preparation of magnetorheological fluids with high sedimentation stability
Oharek, Lukáš ; Kalina, Michal (referee) ; Smilek, Jiří (advisor)
The introduced bachelor thesis focuses on the current issue of stability of magnetorheological fluids in the gravitation field. To prepare stable magnetorheological fluid, influence of additives, particles modification and different carrier fluid are investigated. Regarding the increased viscosity of the carrier fluids, which negatively affect the magnetorheological effect, a magnetorheological fluid containing carbonyl iron particles, which were chemisorbed with non-ionic surfactant Tween 20 was prepared. Mineral oil and water emulsions were used as a carrier fluid, emulsifier Span 80 was used to stabilize the water-in-oil emulsion. Sedimentation stability is improved, at the same time the viscosity of the carrier fluid is increased.
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Properties of fine sediments in the water supply network
Dukát, Petr ; Sucháček, Tomáš (referee) ; Ručka, Jan (advisor)
This bachelor’s thesis deals with properties of fine sediments which occur naturally in water supply pipes. With focus on issues of fine sediments samples literature search was made and measurement methodology, which enables better understanding the behavior of sediment in the water supply network, was determined. During controlled pipes flushing, samples of fine sediments were taken from selected water pipes sections and under laboratory conditions sedimentation test, using measurement methodology, was made. Sedimentation test included the measurement of turbidity for the time necessary to meet the limit value of turibidity given by the government regulation for drinking water. Results of this thesis are important input information for simulating the spread of high turbid water in the water supply network during a turbidity event.
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Hydraulic optimization of horizontal sand catcher
Kulička, Rostislav ; Šálek,, Jan (referee) ; Kriška-Dunajský, Michal (advisor)
This work is focused on the development control system flow area in a standardized horizontal sand trap in the Czech Republic used the majority of constructed wetlands for the capture of solid mineral particles. The goal is the development and validation functions of the flow regulator, providing more uniform process of establishment of mineral particles, respectively. reduction of sedimentation of organic components. The actual design precedes the mathematical description through the HEC-RAS, the results are applied in the design of a laboratory model. Work processes theoretically the standardized sand traps, focuses on the comparison of the required residence time of wastewater in the sedimentation area of establishment with the sedimentation time of sand grain on the selected diameter of 0.8 mm. In laboratory conditions were carried out build sand trap model itself, as well as developed a regulatory element. After resolving structural measurements were taken and compared the results with the ideal state. For putting the controller into practice, when an application is planned at the constructed wetlands in Dražovice village, it will have to the most accurate setting of the regulator.
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Sedimentation of MR fluid at the start of new space lanucher
Berka, Pavel ; Strecker, Zbyněk (referee) ; Roupec, Jakub (advisor)
This bachelor thesis deals with sedimentation behavior of magnetorheological fluid exposed to acceleration 1-6 G. That simulates start of a space launcher. Main goal of this work is to bring new knowledge of MR fluids behavior. Experiment of accelera-ted sedimentation as well as the long term sedimentation is presented, including new method and measuring device developed to measure the sedimentation, in order to compare different commercial MR fluids. Results from this work will be used in development of the new semiactive dum-ping system for carrying load in ESA new space launcher.
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Operational and Technical Condition of Separation Equipment in Water Treatment Plants
Pešout, Jakub ; Roh, Robert (referee) ; Kučera, Tomáš (advisor)
The goal of this thesis was to determine the operational and technical parameters of the separation objects in water treatment. The first part is a theoretical and provides basic information on this issue. The second part contains the evaluation criteria created by the obtained information for individual objects and gained in practice by personal visits of selected treatment plants of water. In the last part we can find application of these criteria in water treatment in practice. There is also included the final evaluation of the researched condition.
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The study of MR fluids sedimentation
Berka, Pavel ; Vimmr, Jan (referee) ; Roupec, Jakub (advisor)
This diploma thesis investigates the accelerated sedimentation of the magnetorheological fuids (MRFs) using centrifuge. Experiments are carried out at room temperature as well as at higher temperatures (40°C, 60°C and 80°C). The development of the new improved measuring device for the sedimentation evaulation is described. Magnetic components of the device were designed using FEM analysis. Newly designed device is verified. To accomplish the experiments at the high temperatures the new heated chamber for experimental centrifuge is designed and constructed. In the next part of the work full experiment of the accelerated sedimentation is performed. At final the empirical model of the sedimetation velocity for various accelerations and temperatures is synthesized.
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A method for the solution of non-spherical (fiber) particles deposition by means of the Fokker-Planck equation for ODF in a laminar flow
Kopečková, Barbora ; Knotek, Stanislav (referee) ; Jícha, Miroslav (advisor)
The Bachelor's thesis deals with a deposition efficiency for a fibers by various mechanisms of a deposition. It explains deposition efficiency by diffusion, by sedimentation and by impaction. The implementation of Peterlin's analytical solution for calculation of the ODF, which is used for individual efficiencies solution, is also mentioned. Afterwards, the thesis summarizes formulas for calculation of particular efficiencies derived for spherical particles and recomputation appropriate parameters for fibers. The purpose of the thesis is to create graphs, which illustrate deposition efficiencies dependence by various mechanisms on the aspect ratio of fibers. Another goal is the graphs creation, which shows juxtaposition for various breathing modes for given deposition mechanisms. The software MATLAB is used for the whole calculation process and graphs plotting.
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Study on kinetic stability of suspension with magnetorheological properties
Vlachová, Kristýna ; Kráčalík, Milan (referee) ; Smilek, Jiří (advisor)
Sedimentation in magnetorheological (MR) fluids is undesirable for many technological applications. For this reason, several ways have been proposed to prevent sedimentation instability. This thesis deals specifically with the addition of a suitable additive. The topic was examined based on available literature and according to it was suggested a procedure for the experimental part. Two types of MR liquids with different composition and preparation method were prepared. The first suspensions included a water-in-oil emulsion as a carrier liquid and Span 80 and Tween 80 as additives. For the second MR fluids, the continuous phase was a blend of bearing oils and the suspension was stabilized with organoclay. In both cases, carbonyl iron particles with a diameter of 1,8–2,3 µm were used. The kinetic stability of the prepared MR fluids was monitored and compared using an analytical centrifuge.
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Use of EIS method for determination of sedimentation in stady liquid
Hradilová, Iva ; Vachovec, Roman (referee) ; Špano, Miroslav (advisor)
Determination of interface between sediment and liquid belongs to common tasks in various fields of industry like sewage and/or water treatment. The aim of presented work is verification of suitability of electrical impedance spectrometry (EIS) method for determination of interface between soil and water. The suitability was verified on three samples of soil. The first one was a sand while other two were loam of different grain sizes. Introduction of both the EIS method and Z-meter III instrument used for measurements is presented in this work too. Within conclusions the suitability of the method and provability in determination of water-soil interface are discussed.
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Hydrodynamic mixing of water-ask mixture in vessel
Holub, Přemysl ; Franc, Zdeněk (referee) ; Habán, Vladimír (advisor)
Master´s thesis Hydrodynamic mixing of water-ash mixture in vessel is interested in describing fluid and solid particles flow in a vessel. The mixing was conducted in cylindrical vessel by a radial nozzle. The goal of the thesis is to describe flow field and places where the most of the particles are descending according to position, depth, flow rate and nozzle orientation in the vessel. An experiment was conducted in order to investigate and document 8 different positions and orientation of the nozzle. Significant changes in flow fields and mixing time were observed. A mathematical model of the vessel with the nozzle was created in Fluent program. Places with the lowest velocities according to the model were in good agreement with places where the most of the solid particles were descending.
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