This doctoral thesis presents an investigation of the physical phenomenon, cavitation, in thermosensible liquids. Cavitation is a phenomenon characterized by vapor generation and condensation in liquid flows, at approximately constant temperature. Cavitation is usually initiated by a local pressure drop in the vicinity of a cavitation nucleus. As the bubble grows, latent heat is supplied from the surrounding liquid to the interface, creating a thermal boundary layer. The consequence is a local decrease of the liquid temperature, which results in a drop of the vapor pressure. This one delays the further development of the bubble, because a greater pressure drop is needed to maintain the process. This phenomenon is known as thermal delay or thermodynamic effect and has a moderation role in the development of cavitation. Thermodynamic effects can be usually neglected in liquids, which critical temperature is much higher than operating temperature, but this is not the case by liquids, which operating temperature is in the vicinity of the critical temperature, like cryogenics. In this doctoral thesis, the thermodynamic effects were experimentally investigated in water at approximate temperature 100°C, by which infrared thermography was used to measured 2D temperature fields within a cavitating flow. Experimental results will aid to better understanding of the phenomenon and to the development and validation of the advanced numerical models, which considerate the thermodynamic effects in the cavitating flow. Correct numerical simulations of the thermodynamic effects present big ground and applicative challenge. Doctoral thesis was led in collaboration with the European Space Agency (ESA) project, where we, together with researchers from LEGI Grenoble (France), develop advanced numerical models for prediction of cavitation within an inducer of the turbopump of the space engine.
D.09 Tutoring for postgraduate students
COBISS.SI-ID: 14545179The European Research Council Consolidator project 2017, with funds of approximately € 2 million for the period of 5 years, was awarded to prof. Dr. Matevž Dular. In this way, prof. Dr. Matevž Dular became the first Slovenian carrier of the ERC project for consolidation of an independent research path. In the past, only three researchers from Slovenia were promoted at the advanced level projects and one researcher was promoted at the beginner level project. Dular's success on the tender is the first success of a researcher from Slovenia at the intermediate consolidator level also. This is an exceptional achievement, as 2538 applications were received at the ERC call from excellent and promising scientists from Europe and the rest of the world. Only 329 projects were accepted for funding. Among these, there were only 9 projects awarded to scientists in the new EU Member States. Evaluation committee for Product and process engineering ranked Dular's project as 27th among 329 accepted projects. The five-year project will recruite seven researchers. The aim of the project is to explore the basic principles of cavitation from a physical, biological and engineering point of view. The research will cover three size classes: i) level of isolated cavitation bubble, ii) level arranged clouds of cavitation bubbles, iii) level of random clouds of cavitation bubbles. It is expected, that understanding of the basic cavitation principles and principles of interactions of cavitation bubbles with pollutants will enable a series of breakthroughs in various scientific fields (techniques, chemistry, biology). The knowledge needed to apply to the ERC call, originates from the projects of cavitation erosion research.
D.01 Chairing over/coordinating (international and national) projects
COBISS.SI-ID: 15909915This is a series of invited lectures given at different universities and conferences (ACCUSIM Summer School, TU-Muenchen,Georg-August-University Göttingen, German Aerospace Center, University of Colorado at Colorado Springs, TU Clausthal, 5th Workshop of ICR, Colloquium on Cavitation and Cavitation Erosion Duisburg-Essen)
B.04 Guest lecture
COBISS.SI-ID: 15777819This is a patent for a cavitation device for use in a method for the energy efficient and ecologically acceptable treatment of water by cavitation.
F.32 International patent
COBISS.SI-ID: 14615835This is a study of a problem of cavitation appearance in a regulatory valve. With different technical approaches we managed to reduce formation of bubbles, reduce noise and prevent damage occurrence on the seat of the valve.
F.07 Improvements to an existing product
COBISS.SI-ID: 15607067