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Title:KAVITACIJSKA EROZIJA V VBRIZGALNIH KOMPONENTAH Z UPORABO POLIDISPERZNEGA KAVITACIJSKEGA MODELA
Authors:ID Greif, David (Author)
ID Kegl, Breda (Mentor) More about this mentor... New window
ID Škerget, Leopold (Comentor)
Files:.pdf DR_Greif_David_2012.pdf (4,97 MB)
MD5: 4A900597F7455A8A46E01E581E51872C
PID: 20.500.12556/dkum/76093764-b67a-4cfb-b810-004cb5687f4b
 
Language:Slovenian
Work type:Dissertation
Typology:2.08 - Doctoral Dissertation
Organization:FS - Faculty of Mechanical Engineering
Abstract:Predložena doktorska disertacija se ukvarja z numeričnim modeliranjem erozijskih efektov kot posledico kavitacijskega toka. Tovrstni tokovi se pojavljajo v različnih industrijskih procesih in so še posebej pomembni v industriji, ki proizvaja ali uporablja komponente za dovod in vbrizg goriva pod visokimi tlaki. Zmožnost numeričnih simulacij tovrstnih notranjih tokov s pomočjo računalniške dinamike tekočin (CFD) omogoča učinkovito oblikovanje vbrizgalnih šob in drugih komponent za dovod goriva, kot so tlačilke, skupni vodi, različni ventili. Ustrezno fizikalno modeliranje samega kavitacijskega toka je predpogoj za določitev agresivnosti obravnavanih pogojev in erozijskih posledic kavitacije. Gonilna sila za nastanek erozijske škode so implozije parnih mehurčkov v kavitacijskem toku. Ponavljajoče se implozije parne faze na površini izpostavljenega materiala sčasoma povzročijo površinske poškodbe. Pravilna ocena nastanka in transporta parne faze v obliki mehurčkov je ključnega pomena. Polidisperzni kavitacijski model v komercialnem CFD programu AVL FIRE je bil uporabljen kot osnova predstavljene disertacije. Materialni erozijski model je bil modificiran in prilagojen v okvirje dinamike tekočin ter implementiran v CFD program. Predvideva, da material ne prenese obremenitev nad mejo plastičnosti materiala in ocenjuje agresivnost kavitacijskega toka kot funkcijo števila implozij mehurčkov na enoto površine in velikosti le-teh ob imploziji na površini. Model omogoča numerične simulacije erozijskih efektov, kar ima izredno vrednost pri oblikovanju komponent za dovod in vbrizg goriva. Kombinacija materialnega erozijskega modela z večfaznim modelom za dinamiko tekočin je unikatna in predstavlja jedro disertacije. Prikazanih je več rezultatov, ki kažejo na zmožnost modela za kvantitativno in kvalitativno oceno verjetnosti nastanka erozijskih poškodb materiala. Prikazane so tudi posledice erodirane površine izvrtin vbrizgalne šobe na širjenje curka goriva. To nakazuje na vpliv erozije na pripravo mešanice goriva in samo zgorevanje.
Keywords:kavitacija, erozija, erozijska škoda, injektor, vbrizgalna šoba, vbrizgalne komponente, pretok skozi šobo
Place of publishing:[Maribor
Publisher:D. Greif]
Year of publishing:2012
PID:20.500.12556/DKUM-36746 New window
UDC:621.436:532.528(043.3)
COBISS.SI-ID:16158230 New window
NUK URN:URN:SI:UM:DK:AK2PVIVK
Publication date in DKUM:01.08.2012
Views:2612
Downloads:233
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FS
:
GREIF, David, 2012, KAVITACIJSKA EROZIJA V VBRIZGALNIH KOMPONENTAH Z UPORABO POLIDISPERZNEGA KAVITACIJSKEGA MODELA [online]. Doctoral dissertation. Maribor : D. Greif. [Accessed 4 April 2025]. Retrieved from: https://dk.um.si/IzpisGradiva.php?lang=eng&id=36746
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Secondary language

Language:English
Title:CAVITATION EROSION IN INJECTION COMPONENTS WITH POLIDISPERSED CAVITATION MODEL
Abstract:This disertation deals with numerical prediction of erosive effects due to cavitation. Such flows appear in many industrial applications and are of special interest within industries producing and using fuel injection components. Ability to predict such internal flows by means of Computational Fluid Dynamics (CFD) allows for efficient design of injectors and other fuel delivery components, such as pumps, common rails, throttles. Accurate modeling of cavitating flows is a prerequisite for the prediction of flow aggressiveness and finally its erosive effects. Driving force for the onset of erosion damage are bubble collapses during vapor condensation. Repetitive implosions on the same surface of the exposed material will eventually result in material damage. Prediction of vapor generation and accurate transport of the bubbles is therefore crucial. Polidispersed cavitation model of AVL FIRE was taken as the basis of the disertation work. Material based erosion model was modified to fit into the fluid dynamics framework and implemented into the CFD code. The model assumes that the material cannot withstand hydrodynamic loads above the yield strength and estimates the aggressiveness of the cavitating flow as function of bubble collapses per unit area and the size of the collapses on the surface. It allows for prediction of erosion effects, which has extreme value in the design process of injection components. Combination of material based erosion model with the multiphase two fluid model is unique and it represents the core of the disertation. Several results are presented to demonstrate model's capability to quantitatively and qualitatively predict probability for erosion existence. Finally, the effects of eroded injector surface on spray propagation are outlined, hinting that erosion inside an injector will affect the combustion process.
Keywords:cavitation, erosion, erosion damage, injectors, injection equipment, injector flow


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