dc.contributor	Veselý Martin, Ing. : 63727
dc.contributor.advisor	Hujer Jan, Ing. Ph.D. : 63725
dc.contributor.author	Kardava, Nugzari
dc.date.accessioned	2021-08-20T12:09:10Z
dc.date.available	2021-08-20T12:09:10Z
dc.date.committed	2022-4-30
dc.date.defense	2021-06-22
dc.date.submitted	2020-11-1
dc.date.updated	2021-6-22
dc.degree.level	Ing.
dc.description.abstract	This master thesis work is done to try and describe processes that occurred during cavitation bubble collapse near a solid boundary, to try and separate cavitation microjet and shock wave impact from the signal received by PVDF sensors. The thesis starts with the introduction of the general terms connected to the cavitation phenomenon itself. Literature related to the bubble interaction phenomena near solid wall and usage of PVDF films is also reviewed. The experimental setup, with the method of bubble generation and used equipment are also described. Two PVDF sensors were fixed to two metal plates in order to receive signals from the bubble collapse, generated by the underwater spark discharge. Calibration of the sensors was done with the ball drop method. The experiments were observed by the Nanosense MKIII CCD camera at 10000 fps. Bubbles were generated at different dimensionless stand-off distances and impacts were further analyzed and compared to different articles. A small chapter is also dedicated to describe the possible problems that can occur during the experiments using PVDF films.Inverse squares law was used to check if the theoretical and experimental shock wave propagation were the same. This law works only for spherical shock sources, results of the experimental values during specific ranges are in the acceptable level with the theoretical model. Maximum impact forces and loading stresses (pressures) are shown and discussed. The exact values of the cavitation microjet are not recorded as a significant event, but several important assumptions were made, especially when the dimensionless stand-off (proximity) parameter is in the range between 0.8 and 1. Double peak-shaped signals are received in this range and these peaks are created by the splash effect (accompanied by the shock waves) due to the microjet and by the moving flow towards the ring (as well can be interpreted as a bubble ring collapse).	cs
dc.description.abstract	This master thesis work is done to try and describe processes that occurred during cavitation bubble collapse near a solid boundary, to try and separate cavitation microjet and shock wave impact from the signal received by PVDF sensors. The thesis starts with the introduction of the general terms connected to the cavitation phenomenon itself. Literature related to the bubble interaction phenomena near solid wall and usage of PVDF films is also reviewed. The experimental setup, with the method of bubble generation and used equipment are also described. Two PVDF sensors were fixed to two metal plates in order to receive signals from the bubble collapse, generated by the underwater spark discharge. Calibration of the sensors was done with the ball drop method. The experiments were observed by the Nanosense MKIII CCD camera at 10000 fps. Bubbles were generated at different dimensionless stand-off distances and impacts were further analyzed and compared to different articles. A small chapter is also dedicated to describe the possible problems that can occur during the experiments using PVDF films.Inverse squares law was used to check if the theoretical and experimental shock wave propagation were the same. This law works only for spherical shock sources, results of the experimental values during specific ranges are in the acceptable level with the theoretical model. Maximum impact forces and loading stresses (pressures) are shown and discussed. The exact values of the cavitation microjet are not recorded as a significant event, but several important assumptions were made, especially when the dimensionless stand-off (proximity) parameter is in the range between 0.8 and 1. Double peak-shaped signals are received in this range and these peaks are created by the splash effect (accompanied by the shock waves) due to the microjet and by the moving flow towards the ring (as well can be interpreted as a bubble ring collapse).	en
dc.description.mark
dc.format	65
dc.format.extent	NO
dc.identifier.signature	V 202103227
dc.identifier.uri	https://dspace.tul.cz/handle/15240/160760
dc.language.iso	an
dc.relation.isbasedon	parKim, K. H., Chahine, G., Franc, J.-P. & Karimi, A. (2014) Advanced experimental and numerical techniques for cavitation erosion prediction. Dordrecht, Springer.par parFranc, J.-P. & Michel, J.-M. (2004) Fundamentals of cavitation. Dordrecht, Kluwer.par parFranc, J.-P., Riondet, M., Karimi, A. & Chahine, G. (2011) Impact load measurement in an Erosive Cavitating Flow. Journal of Fluids Engineering. 133, 121301-1.par parMomma, T. & Lichtarowicz, A (1995) A study of pressures and erosion produced by collapsing cavitation. Wear. 186-187, 425-436.par parWang, Y. C. & Chen, Y. W. (2007) Application of piezoelectric PVDF film to the measurement of impulsive forces generated by cavitation bubble collapse near a solid boundary. Experimental Thermal and Fluid Science. 32, 403-414.par parPiezo Film Sensors Technical Manual (1999), Norrsitown, Measurement Specialties.par
dc.rights	Vysokoškolská závěrečná práce je autorské dílo chráněné dle zákona č. 121/2000 Sb., autorský zákon, ve znění pozdějších předpisů. Je možné pořizovat z něj na své náklady a pro svoji osobní potřebu výpisy, opisy a rozmnoženiny. Jeho využití musí být v souladu s autorským zákonem https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf a citační etikou https://knihovna.tul.cz/document/26	cs
dc.rights	A university thesis is a work protected by the Copyright Act. Extracts, copies and transcripts of the thesis are allowed for personal use only and at one?s own expense. The use of thesis should be in compliance with the Copyright Act. https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf and the citation ethics https://knihovna.tul.cz/document/26	en
dc.rights.uri	https://knihovna.tul.cz/document/26
dc.rights.uri	https://www.mkcr.cz/assets/autorske-pravo/01-3982006.pdf
dc.subject	cavitation	cs
dc.subject	cavitation bubble	cs
dc.subject	bubble collapse	cs
dc.subject	shock waves	cs
dc.subject	microjet	cs
dc.subject	PVDF sensor	cs
dc.subject	cavitation	en
dc.subject	cavitation bubble	en
dc.subject	bubble collapse	en
dc.subject	shock waves	en
dc.subject	microjet	en
dc.subject	PVDF sensor	en
dc.title	Cavitation microjet and shock wave in a signal from impact load measurement	cs
dc.title	Cavitation microjet and shock wave in a signal from impact load measurement	en
dc.type	diplomová práce	cs
local.degree.abbreviation	Navazující
local.degree.discipline	KSA
local.degree.programme	Mechanical Engineering
local.degree.programmeabbreviation	N2301
local.department.abbreviation	KEZ
local.faculty	Fakulta strojní	cs
local.faculty.abbreviation	FS
local.identifier.author	S19000372
local.identifier.stag	41789
local.identifier.verbis
local.identifier.verbis	7333f81e-a900-4736-bdcc-288ef61c5221
local.note.administrators	automat
local.note.secrecy	Povoleno ZverejnitPraci Povoleno ZverejnitPosudky
local.poradovecislo	3227

Cavitation microjet and shock wave in a signal from impact load measurement

Files

Original bundle

Collections