Cavitation is a phenomenon that is commonly observed in turbines, water pumps, and other similar mechanisms which involve the high-speed and high-pressure movement of fluids, as it is the change in state of a material due to a fast pressure change, in particular from the liquid to the solid state. As a result, bubbles of water vapor form within the fluid, which interact with solid surfaces in a short span of time, particularly the creation of jets during the collapse of these bubbles. These jets inflict force on these solid "walls", and
this interaction between bubble and solid wall may cause positive or negative effects, which may be harnessed when better understood.
This project aims to develop an analysis tool, developed in C++, that will aid in the understanding of the dynamics of the cavitation bubble in the context of a dynamic flow system with water as the medium. Investigations are made with the tool on an experimental setup consisting of a spark generator for creating the cavitation bubbles, monitored by a high-speed camera and measured by a polyvinylidene fluoride (PVDF) piezoelectric sensor. The camera is used to observe the development of the bubble and determine its size through image processing of the resulting images that are taken, while the PVDF sensor is a low cost option for measuring pressure on a flat surface, as it can convert pressure into voltage.
In this study, the differences between the single- and double-bubble spark generated setups are observed and analyzed through the optical and acoustical measurement methods. From these comparisons, the project aims to set a baseline for continued study of further specialized measurement and analysis tools of cavitation behavior.
Anotace v angličtině
Cavitation is a phenomenon that is commonly observed in turbines, water pumps, and other similar mechanisms which involve the high-speed and high-pressure movement of fluids, as it is the change in state of a material due to a fast pressure change, in particular from the liquid to the solid state. As a result, bubbles of water vapor form within the fluid, which interact with solid surfaces in a short span of time, particularly the creation of jets during the collapse of these bubbles. These jets inflict force on these solid "walls", and
this interaction between bubble and solid wall may cause positive or negative effects, which may be harnessed when better understood.
This project aims to develop an analysis tool, developed in C++, that will aid in the understanding of the dynamics of the cavitation bubble in the context of a dynamic flow system with water as the medium. Investigations are made with the tool on an experimental setup consisting of a spark generator for creating the cavitation bubbles, monitored by a high-speed camera and measured by a polyvinylidene fluoride (PVDF) piezoelectric sensor. The camera is used to observe the development of the bubble and determine its size through image processing of the resulting images that are taken, while the PVDF sensor is a low cost option for measuring pressure on a flat surface, as it can convert pressure into voltage.
In this study, the differences between the single- and double-bubble spark generated setups are observed and analyzed through the optical and acoustical measurement methods. From these comparisons, the project aims to set a baseline for continued study of further specialized measurement and analysis tools of cavitation behavior.
Cavitation is a phenomenon that is commonly observed in turbines, water pumps, and other similar mechanisms which involve the high-speed and high-pressure movement of fluids, as it is the change in state of a material due to a fast pressure change, in particular from the liquid to the solid state. As a result, bubbles of water vapor form within the fluid, which interact with solid surfaces in a short span of time, particularly the creation of jets during the collapse of these bubbles. These jets inflict force on these solid "walls", and
this interaction between bubble and solid wall may cause positive or negative effects, which may be harnessed when better understood.
This project aims to develop an analysis tool, developed in C++, that will aid in the understanding of the dynamics of the cavitation bubble in the context of a dynamic flow system with water as the medium. Investigations are made with the tool on an experimental setup consisting of a spark generator for creating the cavitation bubbles, monitored by a high-speed camera and measured by a polyvinylidene fluoride (PVDF) piezoelectric sensor. The camera is used to observe the development of the bubble and determine its size through image processing of the resulting images that are taken, while the PVDF sensor is a low cost option for measuring pressure on a flat surface, as it can convert pressure into voltage.
In this study, the differences between the single- and double-bubble spark generated setups are observed and analyzed through the optical and acoustical measurement methods. From these comparisons, the project aims to set a baseline for continued study of further specialized measurement and analysis tools of cavitation behavior.
Anotace v angličtině
Cavitation is a phenomenon that is commonly observed in turbines, water pumps, and other similar mechanisms which involve the high-speed and high-pressure movement of fluids, as it is the change in state of a material due to a fast pressure change, in particular from the liquid to the solid state. As a result, bubbles of water vapor form within the fluid, which interact with solid surfaces in a short span of time, particularly the creation of jets during the collapse of these bubbles. These jets inflict force on these solid "walls", and
this interaction between bubble and solid wall may cause positive or negative effects, which may be harnessed when better understood.
This project aims to develop an analysis tool, developed in C++, that will aid in the understanding of the dynamics of the cavitation bubble in the context of a dynamic flow system with water as the medium. Investigations are made with the tool on an experimental setup consisting of a spark generator for creating the cavitation bubbles, monitored by a high-speed camera and measured by a polyvinylidene fluoride (PVDF) piezoelectric sensor. The camera is used to observe the development of the bubble and determine its size through image processing of the resulting images that are taken, while the PVDF sensor is a low cost option for measuring pressure on a flat surface, as it can convert pressure into voltage.
In this study, the differences between the single- and double-bubble spark generated setups are observed and analyzed through the optical and acoustical measurement methods. From these comparisons, the project aims to set a baseline for continued study of further specialized measurement and analysis tools of cavitation behavior.
State of art in the investigation of the behavior of the single cavitation bubble and bubble structures close to a solid wall.
Definition and preparation of the experimental setup for the measurement of the single bubble and bubbles structures dynamic using acoustical and optical methods.
Preparing the tool for the evaluation of the bubble dynamic experiments.
Realization of experiments for the comparison of the single bubble and bubbles structures dynamic.
Evaluation of the acoustical and optical measurement using the designed tool.
Detailed analysis of the single bubble and bubbles structures dynamic based on the results obtained from the acoustical and optical methods.
Zásady pro vypracování
State of art in the investigation of the behavior of the single cavitation bubble and bubble structures close to a solid wall.
Definition and preparation of the experimental setup for the measurement of the single bubble and bubbles structures dynamic using acoustical and optical methods.
Preparing the tool for the evaluation of the bubble dynamic experiments.
Realization of experiments for the comparison of the single bubble and bubbles structures dynamic.
Evaluation of the acoustical and optical measurement using the designed tool.
Detailed analysis of the single bubble and bubbles structures dynamic based on the results obtained from the acoustical and optical methods.
Seznam doporučené literatury
\matsymb{lbrack}1\matsymb{rbrack} {BRENNEN, Christopher E.} Cavitation and bubble dynamics. {New York: Oxford University Press, 1995. ISBN 0195094093.}
\matsymb{lbrack}2\matsymb{rbrack} {FRANC, Jean-Pierre a Jean-Marie MICHEL.} Fundamentals of cavitation. {Boston: Kluwer Academic Publishers, c2004. ISBN 1402022328.}
\matsymb{lbrack}3\matsymb{rbrack} {KIM, Ki-Han, Georges CHAHINE, Jean-Pierre FRANC a Ayat KARIMI.} Advanced experimental and numerical techniques for cavitation erosion prediction. {Dordrecht: Springer, [2014]. Fluid mechanics and its applications, v. 106.}
Seznam doporučené literatury
\matsymb{lbrack}1\matsymb{rbrack} {BRENNEN, Christopher E.} Cavitation and bubble dynamics. {New York: Oxford University Press, 1995. ISBN 0195094093.}
\matsymb{lbrack}2\matsymb{rbrack} {FRANC, Jean-Pierre a Jean-Marie MICHEL.} Fundamentals of cavitation. {Boston: Kluwer Academic Publishers, c2004. ISBN 1402022328.}
\matsymb{lbrack}3\matsymb{rbrack} {KIM, Ki-Han, Georges CHAHINE, Jean-Pierre FRANC a Ayat KARIMI.} Advanced experimental and numerical techniques for cavitation erosion prediction. {Dordrecht: Springer, [2014]. Fluid mechanics and its applications, v. 106.}
Přílohy volně vložené
1 CD ROM containing:
- source files and executable for CavTools Analysis Tool
- a copy of the masters thesis text
- an archive of the originally used dataset
- reference outputs for double bubble setup (5 mm and 8 mm)
Přílohy vázané v práci
grafy, tabulky
Převzato z knihovny
Ano
Plný text práce
Přílohy
Posudek(y) oponenta
Hodnocení vedoucího
Záznam průběhu obhajoby
Průběh obhajoby je zveřejněn pouze přihlášenému uživateli.