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Hidrodinamičke pojave u centrifugalno vrtložnoj pumpi
Hidrodinamičke pojave u centrifugalno vrtložnoj pumpi
Tihomir Mihalić
Konstrukcija i određivanje radnih karakteristika pumpi je i dalje složen zadatak, prvenstveno zbog velikog broja slobodnih geometrijskih parametara čiji se utjecaj ne može direktno procijeniti. Značajna cijena koštanja konstruiranja pumpi na temelju eksperimentalnih istraživanja, tj. mjerenjima na prototipovima čini računalne simulacije temeljene na računalnoj mehanici fluida (engl. Computational fluid dynamics - CFD) najprihvatljivijim alatom pri konstruiranju i analizi radnih...
Hidroelastični model dinamičkog odziva kontejnerskih brodova na valovima
Hidroelastični model dinamičkog odziva kontejnerskih brodova na valovima
Stipe Tomašević
Znatan porast broja sve većih kontejnerskih brodova u službi širom svijeta skrenuo je pozornost stručne javnosti na potrebu za pouzdanim alatom za određivanje hidroelastičnog odziva takvih brodova. U prvom se poglavlju opisuje političko-ekonomska pozadina koja je do toga dovela, a govori se i o povijesnom razvoju kontejnerskih brodova. Slijedi kraći pregled literature iz područja hidroelastičnosti iz kojeg je vidljiv golemi nesrazmjer – dok je odziv broda u vertikalnoj ravnini...
Hidroelastičnost i dinamička izdržljivost velikih kontejnerskih brodova
Hidroelastičnost i dinamička izdržljivost velikih kontejnerskih brodova
Nikola Vladimir
Hidroelastični proračunski modeli aktualizirani su gradnjom sve većih kontejnerskih brodova, koji imaju specifične konstrukcijske i eksploatacijske značajke. U odnosu na konvencionalne trgovačke brodove, karakterizira ih razmjerno manja krutost (prvenstveno torzijska), što u kombinaciji sa susretnim stanjima mora vezanim za njihovu relativno veću brzinu (oko 27 čv) uvjetuje mogućnost pojave rezonantnog odziva. U ovom doktorskom radu unaprijeĎen je hidroelastični model za...
Identification of the mechanical properties of nodular graphite cast iron via multiaxial tests
Identification of the mechanical properties of nodular graphite cast iron via multiaxial tests
Zvonimir Tomičević
The development of new engineering elements has increased the application of new technologies and materials. This trend has stimulated in the last few decades scientists to describe the material behaviour with more reliable and complex constitutive laws. The latter ones require advanced methods for the identification and validation of material parameters. Digital Image Correlation (DIC) as a full-field measurement technique coupled with Finite Element analyses is suited for identification...
Identifikacija i karakterizacija parametara rada HCCI motora pri pogonu bioplinom
Identifikacija i karakterizacija parametara rada HCCI motora pri pogonu bioplinom
Ante Vučetić
Kontinuiranim povećanjem broja motornih vozila te njihovog utjecaja na globalno zatopljenje, dopuštene vrijednosti onečišćujućih tvari iz motora s unutarnjim izgaranjem sve se više smanjuju te se potiče upotreba obnovljivih izvora energije. Kao potencijalno rješenje za smanjenje emisija štetnih tvari te korištenje obnovljivih izvora energije nameće se HCCI (engl. Homogeneous Charge Compression Ignition) motor pogonjen bioplinom koji kao prednost ima nižu emisiju dušikovih...
Implicitly coupled finite volume algorithms
Implicitly coupled finite volume algorithms
Tessa Uroić
In this thesis a comparison of pressure–velocity coupling algorithms is conducted with special emphasis on the implicit coupling of momentum and pressure equations in a single linear system as an improvement on the conventional segregated methods. The research is done in the scope of the finite volume method, and carried out in foam-extend, a community driven fork of the open source computational fluid dynamics software OpenFOAM. We focus on the equations for steady–state,...
Improvement of the energy planning process for the development of local and regional action plans
Improvement of the energy planning process for the development of local and regional action plans
Nikola Matak
Climate change caused by human activities and their successful mitigation and adaptation to consequences is one of the crucial issues of humanity in the 21st century. One of the most common ways to tackle this issue is local and regional initiatives, which create energy plans for sustainable development. Sustainable energy planning at a local level is first time seen at some level, after the 1970s as a direct consequence of the energy crisis. A serious approach to sustainable local energy...
Improvement of wave statistics for the prediction of long-term responses of marine structures
Improvement of wave statistics for the prediction of long-term responses of marine structures
Antonio Mikulić
The aim of the Thesis is to explore possibilities for improvement of the existing long-term wave statistics for the design and analysis of ships and offshore structures. Thus, the effect of spatial correlation among successive sea states along the shipping route, the effects of intra-annual climate variability and wave directionality, the usage of wave data from different sources, and the practical applicability of environmental contours are explored. The introduction of new...
Increasing the penetration of renewable energy sources by using power to heat technologies in power systems based on coal
Increasing the penetration of renewable energy sources by using power to heat technologies in power systems based on coal
Drilon Meha
The transition of the coal-based energy system is a challenge that can be solved by considering the integration of variable renewable energy sources and synergic effects between electricity, heating, cooling, transport and industrial sectors. This thesis focuses mostly on the integration of variable renewables using power-to-heat technologies in district heating systems. As 70-80% of total energy consumption in buildings takes the form of heat consumed for space heating purposes, spatial...
Indirektni nadzor istrošenosti alata i tvrdoće obratka kod bušenja kamena
Indirektni nadzor istrošenosti alata i tvrdoće obratka kod bušenja kamena
Miho Klaić
Kamen je po svojoj strukturi krhak, nehomogen i anizotropan materijal, čija mehanička svojstva u zoni obrade mogu značajno varirati. Promjenjiva mehanička svojstva, poglavito tvrdoća, imaju veliki značaj kod izbora parametara obrade. Neodgovarajući parametri obrade mogu negativno djelovati na dinamiku trošenja alata, te izazvati lom alata ili obrađivanog materijala uslijed povećanih sila rezanja. Imajući u vidu nemogućnost mjerenja istrošenosti reznog alata tijekom postupka...
Influence of design requirements on the spur gear pair parameters selection
Influence of design requirements on the spur gear pair parameters selection
Daniel Miler
The gear pair design is well-defined within the technical literature, resulting in a straightforward design process. However, transmission performance largely depends on the designer’s skill and experience. Thus, including the optimisation phase in the design process increases the transmission value. Besides the necessary strength requirements, additional characteristics can be ensured. The research was divided into six phases: literature review, the singleobjective optimisation,...

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