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Search results for: ACOUSTIC CAVITATION
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Archives of Acoustics
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Cavitacion erosion, influence of electrochemical corrosion on cavitation - a review
PublicationZjawisko kawitacji polega na narastaniu, a następnie zapadaniu się i implozji pęcherzy wypełnionych gazem lub parami. Zachodzi ono niemalże we wszystkich układach hydrodynamicznych np. w pompach, zaworach, na śrubach okrętowych, turbinach, hydropłatach itp. na skutek lokalnej, gwałtownej zmiany ciśnienia. W większości przypadków jest to zjawisko niepożądane, ponieważ siły generowane podczas implozji pęcherzy kawitacyjnych są tak...
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ACTA ACUSTICA UNITED WITH ACUSTICA
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JOURNAL OF NAVIGATION
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Vortex cavitation as a source of high level acoustic pressure generated by ship propellers
PublicationPraca przedstawia wyniki badań teoretycznych i eksperymentalnych nad mechanizmami fizycznymi generowania wysokiego ciśnienia akustycznego przez kawitujące wiry wierzchołkowe powstające na śrubach okrętowych
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Effective method of treatment of industrial effluents under basic pH conditions using acoustic cavitation – a comprehensive comparison with hydrodynamic cavitation processes
PublicationThe use of acoustic cavitation in advanced oxidation processes (AOPs) is a promising trend in research for treatment of industrial effluents. The paper presents the results of investigations on the use of acoustic cavitation aided by additional oxidation processes (ozonation/H2O2 oxidation/Peroxone/UV-C) for the treatment of effluents from the production of bitumens. Under these conditions, the total contaminant load, expressed...
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The Caustic in the Acoustics of Historic Interiors
PublicationIn the paper, caustics are discussed as ordered forms of focus broadening occurring in concave mirrors. Presented are examples of caustics formed in natural conditions and application of the phenomenon in different fields of science and technology. Against this factual background, the possibility to observe caustics in rooms is pointed out. Special emphasis is put on large rooms of historic character, as such interiors frequently...
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APPLIED ACOUSTICS
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Journal of the Acoustical Society of America
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Analysis of a caustic formed by a spherical reflector: Impact of a caustic on architectural acoustics
PublicationFocusing sound in rooms intended for listening to music or speech is an acoustic defect. Design recommendations provide remedial steps to effectively prevent this. However, there is a category of objects of high historical or architectural value in which the sound focus correction is limited or even abandoned. This also applies to indoor or outdoor concert shells, installations for teaching and acoustic presentations, etc. The...
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Desulfurization of raw naphtha cuts using hybrid systems based on acoustic cavitation and advanced oxidation processes (AOPs)
PublicationA combination of dual-frequency acoustic cavitation (acoustic cavitation) and UV assisted advanced oxidation processes (AOPs) reaction system was developed for desulfurization of raw naphtha used to produce aviation fuels. Various types of oxidants in hybrid systems including hydrogen peroxide, acetic acid, acetone, air and ozone were compared. At optimum oxidant to sulfur compounds molar ratio (rox) of 5.0, the hybrid process...
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Air journal bearing utilizing near-field acoustic levitation: stationary shaft case
PublicationResults of a study to examine a unique idea of self-levitating journal bearing are presented in this paper. the idea represents a radical departure from the current bearing technology. it utilisesacoustic levitation, which relies on the sound energy radiated by an object supporting a load. acoustic levitation has been demonstrated to support loads of up to 10 kg. in order to support a load theacoustic wave emitted by the radiating...
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Tuning of food wastes bioavailability as feedstock for bio-conversion processes by acoustic cavitation and SPC, SPS, or H2O2 as external oxidants
PublicationThe growing amount of food wastes makes them a suitable source for the generation of bioproducts through anaerobic digestion. Appropriate hydrolysis of the feedstock can enhance the efficiency of production of desired products. In this work, acoustic cavitation (AC) was employed as a pretreatment method to enhance hydrolysis stage by the modification of model (potato-based) food waste for increase in soluble chemical oxygen demand...
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Acoustics
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The Journal of Polish Navigational Forum
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Influence of cavitation intensity on the relative cavitation resistance of laser processed C45 carbon steel
PublicationPraca przedstawia badania względnej odporności kawitacyjnej we wstępnym okresie niszczenia laserowo przetopionej 6 kW laserem CO2 stali C45. Badania odporności kawitacyjnej wykonano na stanowisku z wirującą tarczą. Na erodowanej przetopionej warstwie powierzchniowej określono trzy obszary o różnej intensywności oddziaływania obciążeń kawitacyjnych. Określano wielkość odkształceń plastycznych w analizowanych obszarach, spowodowanych...
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AVIATION
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Multi-objective optimization of the cavitation generation unit structure of an advanced rotational hydrodynamic cavitation reactor
PublicationHydrodynamic cavitation (HC) has been widely considered a promising technique for industrial-scale process intensifications. The effectiveness of HC is determined by the performance of hydrodynamic cavitation reactors (HCRs). The advanced rotational HCRs (ARHCRs) proposed recently have shown superior performance in various applications, while the research on the structural optimization is still absent. The present study, for the...
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Effect of the Cavitation Generation Unit Structure on the Performance of an Advanced Hydrodynamic Cavitation Reactor for Process Intensifications
PublicationThe advanced rotational hydrodynamic cavitation reactors (ARHCRs) that appeared recently have shown obvious advantages compared with conventional devices in process intensifications. In ARHCRs, the cavitation generation unit (CGU) located on the rotor and stator basically determines their performance. For the first time, the present study investigated the effect of the CGU structure on the performance of a representative ARHCR...
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BUILDING ACOUSTICS
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Acoustics Australia
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Acoustics Bulletin
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TransNav - The International Journal on Marine Navigation and Safety of Sea Transportation
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Hardness measurements for assessment of cavitation intensity
PublicationArtykuł opisuje możliwość zastosowania pomiarów teardości erodowanego materiału do oceny natężenia zjawiska kawitacji. Proponowana metoda zakłada, że cała energia implodujących pęcherzyków kawitacyjnych zamieniana jest na przyrost twardości warstwy wierzchniej materiału
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Difficulties with evaluating resistance of materials to cavitation.
PublicationW pracy dokonano analizy wyników Międzynarodowego Testu Erozji Kawitacyjnej (ICET), któremu koordynował Instytut Maszyn Przepływowych Polskiej Akademii Nauk (IMP PAN) w Gdańsku. Kluczowe parametry wpływające na zmianę przebiegu krzywych erozji uzyskanych na stanowiskach badawczych zostały wskazane. Wykazano konieczność przeprowadzenia badań w zakresie oceny wpływu efektu skali. Zaprezentowano wyniki uzyskane na stanowiskach magnetostrykcyjnych...
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Scale effects in cavitation erosion of materials
PublicationW pracy przedstawiono wpływ wielkości objętości erodowanego materiału na przebieg krzywych erozyjnych. Przedstawiono również niektóre wyniki Międzynarodowego Testu Kawitacyjnego.
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Estimation of cavitation erosion resistance of materials
PublicationW pracy przedstawiono ocenę odporności kawitacyjnej 17 materiałów. Do opisu odporności kawitacyjnej zaproponowano nowy wskaźnik liczbowy uwzględniający długość okresu inkubacji, maksymalną prędkość niszczenia oraz czas po którym wystąpi maksymalna prędkość niszczenia materiału. Zaproponowany wskaźnik porównano ze wskaźnikiem δcav, który reprezentuje całą krzywą erozji kawitacyjnej materiału.
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Cavitation Erosion – Phenomenon and Test Rigs
PublicationThe cavitation and cavitation erosion phenomenon have been shortly presented. The main four types of test rigs to investigate the cavitation erosion resistance have been shown. Each type of test design is described and an example of a design is shown. A special attention has been payed to the designs described in the International ASTM Standards: a vibratory design and a cavitating jet cell. There was shown that the design of a...
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The resistance of S235JR steel to cavitation erosion
PublicationThe erosion resistance of S235JR steel to flow cavitation was investigated. In order to understand an influence of steel properties and cavitation intensities on the degradation mechanisms, low-carbon S235JR steel was tested in the as-received state and after thermal treatment (annealing) under four different flow velocities. Annealing decreased steel hardness, which made S235JR steel less resistant to cavitation erosion. The performed...
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Cavitation erosion degradation of Belzona® coatings
PublicationIn hydrocarbon and maritime industry there is a constant need of materials and coatings withstanding severe conditions. One of adverse phenomena present there is cavitation erosion. The paper presents evaluation of cavitation resistance of three different steel coatings. Belzona 2141 (ACR-Fluid Elastormer), 1321 (Ceramic S-Steal) and 5831 (ST-Barrier) were deployed on P110 steel and subjected to ultrasound cavitation in distilled...
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Jacek Marszal dr hab. inż.
PeopleJacek Marszal received M.Sc., Ph.D. and D.Sc. degrees in Telecommunications Engineering at Gdansk University of Technology (GUT), Poland, in 1977, 1989 and 2014 respectively. His scientific specialty is underwater acoustics. Immediately after graduation in 1977, he started working at the Gdansk University of Technology, where since 2015 he is the Head of the Department of Marine Electronic Systems. He is the author and co-author...
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Interaction between acoustic and non-acoustic mode in bubbly liquid
PublicationThe nonlinear interaction of acoustic and entropy modes in a bubbly liquid is the subject of investigation. Thedynamic equation governing an excess density of the entropy mode is derived. Nonlinearity and dispersion are the reasons forexcitation of the entropy mode. The nonlinear interaction of modes as a reason for bubble to grow due to sound, is discovered.Some numerical examples of the modes interactions are made.
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Gyroscopy and Navigation
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Gravitation & Cosmology
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Satellite Navigation
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On the importance of volume of eroded material for cavitation erosion
PublicationW pracy przedstawiono model matematyczny opisujący wpływ objętości erodowanego materiału na przebieg krzywych erozji kawitacyjnej
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An Experimental and Numerical Study of Tip Vortex Cavitation
PublicationArtykuł przedstawia eksperymentalne i numeryczne badanie kawitujacych wirów wierzchołkowych. Eksperymenty przeprowadzono w tunelu kawitacyjnym na modelu płata nośnego, wykonując pomiary pola prędkości wokół wiru przy pomocy metody Particle Image Velocimetry (PIV). Równolegle przeprowadzono numeryczne symulacje kawitującego wiru wierzchołkowego dla różnych parametrów przepływu. Symulacje wykonano programami Fluent i CFX, stosując...
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Cavitation-Based Processes for Water and Wastewater Treatment
PublicationCavitation based on advanced oxidation processes (Cav-AOPs) is interesting alternatives for already implemented wastewater treatment technologies. Destructive and strongly undesirable phenomena in the industry, i.e., cavitation, revealed to be useful in a positive manner as a source of energy for chemical reactions. During the implosion of cavitation bubbles, focused energy and resulting high temperature and pressure allows to...
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Cavitation Erosion Resistance Influence of Material Properties
PublicationThe cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components,...
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Interaction of Acoustic and Thermal Modes in the Vibrationally Relaxing Gases. Acoustic Cooling
PublicationThe dynamic equation which governs an excess temperature associated with the thermal mode in vibrationally relaxing gas is derived. The nonlinear transfer of acoustic energy to the energy of the thermal mode in a relaxing gas causes slow variation of temperature with time. The nal dynamic equation is instantaneous. All types of sound, including aperiodic, may be considered as an acoustic source of corresponding heating or cooling....
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Acoustic streaming caused by some types of aperiodic sound. Buildup of acoustic streaming
PublicationThe analysis of streaming caused by aperiodic sound of different types (switched on at transducer sound or sound determined by initial conditions) is undertaken. The analysis bases on analytical governing equation for streaming Eulerian velocity, which is a result of decomposition of the hydrodynamic equations into acoustic and non-acoustic parts. Its driving force (of acoustic nature) represents a sum of two terms; one is the...
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Detection and localization of selected acoustic events in acoustic field for smart surveillance applications
PublicationA method for automatic determination of position of chosen sound events such as speech signals and impulse sounds in 3-dimensional space is presented. The evens are localized in the presence of sound reflections employing acoustic vector sensors. Human voice and impulsive sounds are detected using adaptive detectors based on modified peak-valley difference (PVD) parameter and sound pressure level. Localization based on signals...
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Removal of Naphthalene from Wastewater Using Hydrodynamic Cavitation
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Cavitation Erosion of Nodular Cast Iron - Microstructural Effects
PublicationThe paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features...
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Mathematical description and evaluation of cavitation erosion resistance of materials.
PublicationPrzedstawiono matematyczny opis erozji kawitacyjnej materiałów. Model opisuje wpływ własności mechanicznych materiału takich jak: względna odporność na plastyczne odkształcanie powierzchni a także współczynnika intensywności naprężeń wzmocnionej warstwy wierzchniej na przebieg erozji kawitacyjnej. Zaproponowano również nowy współczynnik opisujący ilościowo odporność kawitacyjną materiałów jako funkcję czasu inkubacji maksymalnej...
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Mathematical description and evaluation of cavitation erosion resistance of materials.
PublicationW pracy przedstawiono matematyczny model opisujący erozję kawitacyjną materiałów oparty o rozkład prawdopodobieństwa Weibulla. Model oposuje wpływ własności mechanicznych materiału na przebieg krzywych erozji kawitacyjnej.
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Scale effects in cavitation experiments with marine propeller models
PublicationPraca zawiera przegląd specyficznych efektów skali występujących w badaniach kawitacyjnych modeli śrub okrętowych oraz analizę ich wpływu na prognozowane osiągi śrub okrętowych w skali rzeczywistej.
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Cavitation behavior of the SUPERSTON alloy after laser treatment
PublicationResults of laser treatment at cryogenic conditions and its influence on microstructure, microhardness and cavitation resistance of the SUPERSTON alloy are presented in this paper. Obtained results point at possibility of the increase hardness and cavitation resistance of the parts worked in cavitation conditions.
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Cavitation Erosion of P110 Steel in Different Drilling Muds
PublicationThe P110 steel specimens were subjected to ultrasonic cavitation erosion in different compositions of drilling muds and surfactant additive. The test procedure was based on ASTM-G-32 standard recommendations. API 5CT-P110 steel is used for pipes in oil and gas industry. The harsh environment and high velocity of flows poses corrosive and erosive threat on materials used there. The composition of drilling fluid influences its rheological...
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Advances in Acoustics and Vibration
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