magistrsko delo
Damijan Kanduti (Author), Jure Marn (Mentor), Leopold Škerget (Co-mentor)

Abstract

V magistrski nalogi smo obravnavali zmesi pepela in vode. Zmesi pepela in vode štejemo med nenewtonske dilatantne tekočine, kar pomeni, da napetostni tenzor ni linearno odvisen od tenzorja deformacijskih hitrosti. Viskoznost zmesi pepela in vode ni konstantna veličina, ampak je odvisna od deformacijske hitrosti in strižne napetosti. Pretakanje zmesi pepela in vode po cevovodih lahko proučujemo le, če poznamo njihove fizikalne lastnosti in vpliv zunanjih dejavnikov na te lastnosti. V delu je podana zasnova eksperimenta in laboratorijskih analiz za določevanje reoloških lastnosti tekočin (zmesi pepela in vode). Prikazana je zasnova cevnega (kapilarnega) viskozimetra in postopek izvajanja eksperimenta z obdelavo izmerjenih veličin. Obdelana je tudi analiza merilne negotovosti eksperimenta. Podane so laboratorijske analize vzorcev pepela ter zmesi pepela in vode, ki so prispevale k izdelavi reološkega modela tekočin. Obdelani so rezultati treh zmesi pepela in vode s trikratno ponovljivostjo, ki bazirajo na dvajsetih vzorcih pepela. Določitev reološkega obnašanja je izvedena eksperimentalno s cevnim (kapilarnim) viskozimetrom. S cevnim (kapilarnim) viskozimetrom so izvedene meritve tlaka in masnega pretoka zmesi pepela in vode. S spreminjanjem tlaka v cevnem (kapilarnem) viskozimetru smo spreminjali masni pretok. Tako smo dobili povezavo med deformacijsko hitrostjo in strižno napetostjo iz meritev tlačnega gradienta in prostorninskega toka zmesi pepela in vode skozi cev kapilarnega viskozimetra, pri ustaljenem, laminarnem in izotermnem toku. Nenewtonsko viskozno obnašanje zmesi pepela in vode smo opisali z dvema matematičnima modeloma, in sicer s potenčno enačbo (dvoparametrični reološki model - Potenčni zakon) in s kvadratno enačbo (matematičnim modelom polinoma druge stopnje).

Keywords

mehanika tekočin;nenewtonske tekočine;eksperimentalno delo;cevni (kapilarni) viskozimeter;reološki modeli;magistrske naloge;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UM FS - Faculty of Mechanical Engineering
Publisher: [D. Kanduti]
UDC: 532.135:532.542(043.2)
COBISS: 19927574 Link will open in a new window
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Other data

Secondary language: English
Secondary title: Eksperimental determination of ash suspension flow
Secondary abstract: Ash and water mixture is discussed in this master's thesis. This mixture is classified as non-Newtonian dilatant fluid, which signifies that shear stress tensor is not linearly dependent on shear rate tensor. Viscosity of ash and water mixture is no longer a constant quantity, but is dependent on shear rate and shear stress. The flow of ash and water mixture in pipelines can be analysed if we know its physical properties and the influence of external factors on these properties, respectively. The scheme of experimental set-up and laboratory analyses for determining the properties of rheological fluids (ash and water mixture) is given in this thesis. The scheme of pipe (capillary) viscometer and the implementation process of the experiment with the processing of measured quantities are also described. The analysis of measurement uncertainty has also been discussed. Laboratory analyses of ash samples and ash and water mixture samples have been given and have contributed to the implementation of rheological model for these fluids. Results of three ash and water mixtures (which are based on twenty ash samples) with three times the repeatability have been processed. The process of determining the rheological behaviour was performed through experimental work with capillary viscometer. The measurements of pressure and mass flow rate for ash and water mixture were implemented in capillary viscometer. The mass flow rate was varied by varying the pressure in the pipe (capillary) of the viscometer. Thus the relationship between shear rate and shear stress was obtained from measurements of the pressure gradient and the volumetric flow rate of the ash and water mixture through the pipe (capillary) viscometer, under steady, laminar and isothermal flow. Non-Newtonian viscous behaviour was described with two mathematical models – a power equation (two-parameter rheological model – Power Law) and a quadratic equation (the mathematical model of second degree polynomial equation).
Secondary keywords: mechanics fluid;non-newtonian fluid;experimental work;capillary viscometer;rheological models;
URN: URN:SI:UM:
Type (COBISS): Master's thesis
Thesis comment: Univ. v Mariboru, Fak. za strojništvo
Pages: XI, 112 f.
ID: 9155169