Abstract
Cavitation is physical phenomenon of crucial impact on the operation range and service lifetime of the hydraulic machines (pumps, turbines, valves etc.). Experimental measurement of cavitation is expensive and time consuming process, while some important characteristic of the flow are difficult to measure due to the nature of the phenomenon. Current possibilities of computational fluid dynamics provide a way for deeper understanding of cavitation which is important for many applications in the hydraulic machines industry such as expanding operation range or extending lifetime of the hydraulic machines. Simplified model consists of NACA 2412 hydrofoil with 8 degrees angle of attack fixed in between the walls of cavitation tunnel. Present investigation focuses on comparison of vapor volume fractions obtained by 3D CFD simulations and high speed visualization of the real cavitation phenomena. Several operating regimes corresponding to different cavitation numbers are studied with aim to assess the dynamics of the separated cavitating sheets/clouds
Highlights
Cavitation is physical phenomenon of vapor phase creation in liquid flow caused by pressure reduction at constant ambient temperature
The interaction of the separated flow and cavitation leads to a complex flow, which is still quite challenging to be simulated correctly due to its physical complexity and dynamic behaviour
The results described in the present contribution confirmed that it could be still quite challenging to simulate dynamics of complex multiphase flow properly
Summary
Cavitation is physical phenomenon of vapor phase creation in liquid flow caused by pressure reduction at constant ambient temperature. Since the cavity filled with vapor is still part of the flow it is convected downstream to a region of higher pressure, where cavity collapses. Specific volume of vapor is higher than specific volume liquid, the inception and collapse of cavity is accompanied by emission of pressure shocks and acoustic waves. In case of wall presence in the area of collapsing cavities the rapid wear of surfaces called erosion occurs, while the wear of the surfaces of the hydrofoil is highly influenced by the unsteady cloud shedding. Cavitation phenomenon could be characterized by the dimensionless cavitation number σ. It should be mentioned that computation of cavitation number was based on the characteristics of the flow in the inlet section of the test part of cavitation tunnel (rectangular shape). The interaction of the separated flow and cavitation leads to a complex flow, which is still quite challenging to be simulated correctly due to its physical complexity and dynamic behaviour
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
