20.500.12556/DKUM-19504 VPLIV TRDNO-KAPLJEVITIH ZMESI NA OBRATOVALNE KARAKTERISTIKE HIDRAVLIČNIH STROJEV IMPACT OF SOLID-LIQUID MIXTURES ON THE OPERATING CHARACTERISTICS OF HYDRAULIC MACHINES Doktorska disertacija obravnava vpliv delcev na obratovalne karakteristike hidravličnih strojev. Zastavljen problem je določiti vpliv delcev na razvoj kavitacije in hrupa, ter zapisati matematično fizikalni model vključitve disperzne faze delcev na razvoj kavitacije v programskem okolju CFD. V delu je izdelana podrobnejša analiza disperznih delcev v rečni vodi, ter njihov vpliv na obratovanje treh različnih hidroelektrarn. V eksperimentalnih raziskavah je bila največja pozornost namenjena določitvi odvisnosti masne koncentracije delcev na razvoj kavitacije in hrupa. Poglobljene raziskave so potekale na določitvi vpliva delcev na začetno kavitacijsko število. Eksperimentalne meritve so nam bile vodilo za potrditev rezultatov numeričnega modeliranja. V CFD smo kapljevito in parno fazo zajeli kot zvezdno fazo. Delce v večfaznem toku smo opredelili kot disperzno fazo. Numerično modeliranje kapljevite, parne in disperzne faze je potekalo z Euler-Euler pristopom, na osnovi Navier Stokesovih enačb. Uporabili smo kavitacijski model zasnovan na podlagi Rayleigh-Plessetove enačbe. Zapisali smo fizikalno matematični model vpliva delcev na razvoj kavitacije, v katerega smo vključili disperzno fazo. Posebej smo se osredotočili na strižno viskoznost trdnine. S parametričnim pristopom smo definirali in zapisali empirični nastavek, v odvisnosti od masne koncentracije delcev. Rezultate numeričnega modeliranja večfaznega toka, smo primerjali z eksperimentalnimi rezultati. This doctoral dissertation examines the impact of particles on the operating characteristics of hydraulic machines. The main goal was to determine the impact of particles on the development of cavitation and noise, and to establish a mathematical physical model integrating the effect of disperse phase particles on the development of cavitation within the CFD software environment. In this work a more detailed analysis of dispersed particles in the river water and their impact on the operation of three different hydroelectric power plants was made. In the experimental studies the focus was made on determining the dependence the development of cavitation and noise on mass concentration of particles in the fluid. More detailed research was conducted on determining the impact of particles on the initial cavitation number. Experimental measurements served to confirm results of numerical modelling. In CFD, we used liquid and vapour phase as continuous phases. The particles in a multiphase flow were defined as the dispersed phase. Numerical modelling of liquid, vapour and dispersed phase was conducted with the Euler-Euler approach, based on the Navier Stokes equations. We used a cavitation model based on Rayleigh-Plesset equation. We developed mathematical physical model of particles’ impact on the development of cavitation, in which the dispersed phase was included. We particularly focused on modelling the shear viscosity of the solids. With the parametric approach we described and developed an empirical formula implementing the mass concentration of particles. The results of the numerical modelling of multiphase flow were compared with the experimental results. hidravlični stroji večfazni tok kavitacija hrup delci numerično modeliranje hydraulic machines multi-phase flow cavitation noise particles numerical modelling true true false B. Gregorc] Slovenski jezik Angleški jezik Doktorska disertacija 2011-07-26 21:40:18 2011-07-28 07:18:32 2022-04-13 15:26:04 2023-12-25 03:15:53 2011 0 [Maribor 0 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 621.224:620.193.16(043.3) 257084672 URN:SI:UM:DK:828MR2R8 DR_Gregorc_Bostjan_2011.pdf DR_Gregorc_Bostjan_2011.pdf 1 6A3BEF67B5AE2F84BB92BA1395401AB2 68c778d34cce82df358b08e9906562e2bf9162c81f9cbcd1c0cd8eccca729c87 6b05c7ff-7c05-11eb-bb7a-00155d0001ca 20.500.12556/dkum/47fbcd44-975e-412f-a578-8d4f6840bb13 https://dk.um.si/Dokument.php?lang=slv&id=23816 Fakulteta za strojništvo 0 0 0