Magnetic fluids used in the fluids engineering

Magnetické kapaliny jsou kombinací kapalin a magnetických materiálů a jsou dnes používány v mnoha různých aplikacích. Tato práce popisuje vlastnosti magnetoreologických (MR) kapalin a ferrokapalin, jejich rozdíly a možnosti praktických aplikací. Dále se práce věnuje příkladům praktických aplikací. Jsou uvedeny příklady dnes vyráběných magnetických kapalin a porovnání vybraných parametrů.Magnetic fluids are unique combination of fluids and magnetic materials and they are today used in many different applications. This thesis describes the characteristics of magnetorheological (MR) fluids and ferrofluids, their differncies and possibilities of practical uses. Examples of current magnetic fluids are given and comparison of their selected properties.

Improving of hydraulic properties of swirl turbines

Tato diplomová práce se zabývá návrhem geometrie lopatek oběžného kola vírové turbíny pro různě hustou lopatkovou mříž na dané parametry Q11 = 1,9 [m3s-1], n11 = 170 [min-1], H = 2,5 m , a  = 0,8., s cílem zjistit, jak se budou lišit kola s velkým počtem lopatek proti návrhu s méně lopatkami. Z takto získaných návrhů byly spočítány a porovnány charakteristiky pro tří, sedmi a devítilopatkové kolo.This diploma thesis describes design of blade geometry of swirl turbines with different blade row density for given parameters Q11 = 1,9 [m3s-1], n11 = 170 [min-1], H=2,5 m, and =0,8. Goal is to found out differences between designs with high count of runner blades and design with fewer blades. Comparison of computed characteristics of three, seven and nine bladed runners is given.

Influence of partial immersion on steel plate dynamic properties

Eigenfrequency of object drops when it is submerged in the water compared to an air exposition. In this article the effect of partial submersion on dynamic properties of steel plate is investigated. Changes differ by a type of particular modeshape because of relative position of nodes and antinodes to free surface. Dynamic properties are influenced mainly by position of antinodes, in which maximal displacement occurs. Comparison of experiment, FEM simulation in ANSYS and custom code analytical solution is presented. Added effects of fluid on the steel plate are discussed

Influence of partial immersion on steel plate dynamic properties

Eigenfrequency of object drops when it is submerged in the water compared to an air exposition. In this article the effect of partial submersion on dynamic properties of steel plate is investigated. Changes differ by a type of particular modeshape because of relative position of nodes and antinodes to free surface. Dynamic properties are influenced mainly by position of antinodes, in which maximal displacement occurs. Comparison of experiment, FEM simulation in ANSYS and custom code analytical solution is presented. Added effects of fluid on the steel plate are discussed

Quarter wavelength resonator in experiment and simulation

Quarter wavelength resonator provides a mean to create a pressure drop at a specified frequency. Design of hollow cylinder connected radially to a pipe was used and different lengths of this tuned resonator were measured. Correlation with computational approach using finite element method analysis (FEM) with ANSYS acoustics capabilities was achieved. Analytical formula for a length of a quarter wavelength resonator is compared to an experimental measurement data and simulation

Bulk viscosity of water in acoustic modal analysis and experiment

Bulk viscosity is an important factor in the damping properties of fluid systems and exhibits frequency dependent behaviour. A comparison between modal analysis in ANSYS Acoustics, custom code and experimental data is presented in this paper. The measured system consists of closed ended water-filled steel pipes of different lengths. The influence of a pipe wall, flanges on both ends and longitudinal waves in the structural part were included in measurement evaluation. Therefore, the obtained values of sound speed and bulk viscosity are parameters of the fluid. A numerical simulation was carried out only using fluid volume in a range of bulk viscosity. Damping characteristics in this range were compared to measured values. The results show a significant influence of sound speed and subsequently, the use of sound speed value regressed from experimental data yields a better fit between the measurement and the computation

Druhá viskozita vody v akustické modální analýze a v experimentu

Bulk viscosity is an important factor in the damping properties of fluid systems and exhibits frequency dependent behaviour. A comparison between modal analysis in ANSYS Acoustics, custom code and experimental data is presented in this paper. The measured system consists of closed ended water-filled steel pipes of different lengths. The influence of a pipe wall, flanges on both ends and longitudinal waves in the structural part were included in measurement evaluation. Therefore, the obtained values of sound speed and bulk viscosity are parameters of the fluid. A numerical simulation was carried out only using fluid volume in a range of bulk viscosity. Damping characteristics in this range were compared to measured values. The results show a significant influence of sound speed and subsequently, the use of sound speed value regressed from experimental data yields a better fit between the measurement and the computation

Additional effects of fluid on the piston

Additional effect of fluid on the solid body is often ignored phenomenon. Although it is possible to do an analytic derivation of equations describing additional effects for many various conditions, it can be difficult to solve them. The paper shows pressure pulsations in the pipe with piston solved by transfer matrix and harmonic analysis with ANSYS Acoustics, where effect of second viscosity is included

Přídavné účinky tekutiny na píst

Additional eect of uid on the solid body is often ignored phenomenon. Although it is possible to do an analytic derivation of equations describing additional eects for many various conditions, it can be dicult to solve them. The paper shows pressure pulsations in the pipe with piston solved by transfer matrix and harmonic analysis with ANSYS Acoustics, where eect of second viscosity is included.Přídavný účinek tekutiny na pevné těleso je často ignorovaný jev. Přestože je možné provést analytické odvození rovnic popisujících přídavné účinky pro mnoho různých podmínek, jejich řešení může být obtížné. Článek řešení tlakových pulsací v trubce s pístem pomocí přenosových matic a harmonickou analýzu v softwaru ANSYS Acoustic. Vliv druhé viskozity je zahrnut