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Wyniki wyszukiwania dla: HYDRODYNAMIC CAVITATION (HC)
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Multi-objective optimization of the cavitation generation unit structure of an advanced rotational hydrodynamic cavitation reactor
PublikacjaHydrodynamic 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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Removal of Naphthalene from Wastewater Using Hydrodynamic Cavitation
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Effect of the Cavitation Generation Unit Structure on the Performance of an Advanced Hydrodynamic Cavitation Reactor for Process Intensifications
PublikacjaThe 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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Recent advances in hydrodynamic cavitation-based pretreatments of lignocellulosic biomass for valorization
PublikacjaRecently, the hydrodynamic cavitation (HC)-based pretreatment has shown high effectiveness in laboratories and even in industrial productions for conversion of lignocellulosic biomass (LCB) into value-added products. The pretreatment capability derives from the extraordinary conditions of pressures at ∼500 bar, local hotspots with ∼5000 K, and oxidation (hydroxyl radicals) created by HC at room conditions. To promote this emerging...
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Combination of hydrodynamic cavitation and SR-AOPs for simultaneous degradation of BTEX in water
PublikacjaHydrodynamic cavitation (HC) is an emerging technology gaining interest in water treatment for use in elimination of a wide range of organic pollutants. The energy released during cavitation phenomenon has number of applications and, particularly, it can be utilized for activation of persulfate (PS) and peroxymonosulfate (PMS). In the present study, hybrid techniques: HC combined with persulfates – HC-PS and HC-PMS were tested...
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Disinfection characteristics of an advanced rotational hydrodynamic cavitation reactor in pilot scale
PublikacjaHydrodynamic cavitation is a promising technique for water disinfection. In the present paper, the disinfection characteristics of an advanced hydrodynamic cavitation reactor (ARHCR) in pilot scale were studied. The effects of various flow rates (1.4–2.6 m3/h) and rotational speeds (2600–4200 rpm) on the removal of Escherichia coli (E. coli) were revealed and analyzed. The variation regularities of the log reduction and reaction...
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Decolorization of Congo red via hydrodynamic cavitation in combination with Fenton’s reagent
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The role of hydrodynamic cavitation in tuning physicochemical properties of food items: A comprehensive review
PublikacjaBackground: Today, food processing industries are looking for alternative technologies with an eco-friendly character for the processing of food, beverages and agricultural crops. Ideally, such technologies may preserve the original properties of the food products while reaching their primary target of application. Scope and approach: At this point, hydrodynamic cavitation (HC) is recognized as one of the potential technologies...
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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
PublikacjaThe 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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Novel strategies to enhance hydrodynamic cavitation in a circular venturi using RANS numerical simulations
PublikacjaHydrodynamic cavitation is a popular advanced oxidation technique and it has received wide range of applications from waste water treatment to the nanoparticles synthesis in recent years. The enhancement of the intensity of the hydrodynamic cavitation is always been an emerging field of research. Within this framework, we have proposed and investigated three distinct strategies to enhance the intensity of cavitation in a circular...
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Hybrid systems using hydrodynamic cavitation/ultrasound/Fenton processes for effective treatment of wastewater
PublikacjaThe present situation of rapid growth in industrialization generates complex recalcitrant pollutants that are challenging to degrade by conventional wastewater treatment processes. The new generation pollutants such as non-metals in cosmetics or household cleaning chemicals and radioactive compounds which are recalcitrant are the emerging threat to the ecosystem. The headstrong micro and macro pollutants present in wastewater are...
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Synergistic effects of hybrid advanced oxidation processes (AOPs) based on hydrodynamic cavitation phenomenon – A review
PublikacjaHigh-performance water treatment systems based on cavitational processes have received an increasing interest of scientific community in the past few decades. Numerous studies indicated the advantageous application of hydrodynamic cavitation as an alternative, reagent-free treatment method of various pollutants in water. Both approaches were proved as an effective method to achieve mineralization of many organic contaminants as...
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Ultrafast degradation of brilliant cresyl blue under hydrodynamic cavitation based advanced oxidation processes (AOPs)
PublikacjaThe study highlights effectiveness of hydrodynamic cavitation (HC) in the degradation of effluents polluted by Brilliant Cresyl Blue (BCB) dye. Optimal process parameters were cavitation number 0.27, inlet pressure 1.70 bar, temperature 20 °C and pH 7. The efficiency of HC was investigated in combination with other advanced oxidation processes, including the addition of external oxidants (hydrogen peroxide, ozone, and sodium persulfate)...
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Hydrodynamic cavitation based advanced oxidation processes: Studies on specific effects of inorganic acids on the degradation effectiveness of organic pollutants
PublikacjaThe use of cavitation in advanced oxidation processes (AOPs) to treat acidic effluents and process water has become a promising trend in the area of environmental protection. The pH value of effluents – often acidified using an inorganic acid, is one of the key parameters of optimization process. However, in the majority of cases the effect of kind of inorganic acid on the effectiveness of degradation is not studied. The present...
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Activated sodium percarbonate-ozone (SPC/O3) hybrid hydrodynamic cavitation system for advanced oxidation processes (AOPs) of 1,4-dioxane in water
PublikacjaHydrodynamic cavitation (HC) was employed to activate sodium percarbonate (SPC) and ozone (O3) to degrade recalcitrant 1,4-dioxane. The degradation efficiency > 99 % with a rate constant of 4.04 × 10−2 min−1 was achieved in 120 min under the optimal conditions of cavitation number (Cv) 0.27, pH 5, molar ratio of oxidant to pollutant (rox) 8, ozone dose of 0.86 g h−1 under 25 ± 2 °C with initial concentration of 1,4-dioxane 100...
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Effective method of treatment of effluents from production of bitumens under basic pH conditions using hydrodynamic cavitation aided by external oxidants
PublikacjaUtilization of cavitation in advanced oxidation processes (AOPs) is a promising trend in research on treatment of industrial effluents. The paper presents the results of investigations on the use of hydrodynamic cavitation aided by additional oxidation processes (O3/H2O2/Peroxone) to reduce the total pollution load in the effluent from the production of bitumens. A detailed analysis of changes in content of volatile organic compounds...
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A comparative study on the decolorization of Tartrazine, Ponceau 4R, and Coomassie Brilliant Blue using persulfate and hydrogen peroxide based Advanced Oxidation Processes combined with Hydrodynamic Cavitation
PublikacjaDecolorization of Ponceau 4R, Tartrazine, and Coomassie Brilliant Blue (CBB) was studied using hybrid processes of hydrodynamic cavitation (HC) with potassium persulfate (KPS) and hydrogen peroxide (H2O2). The different properties of these dyes such as hydrophobicity, molecular structures, and molecular weights provided this opportunity to investigate the effects of these factors by comparing the decolorization values of the dyes....
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Cavitation based cleaner technologies for biodiesel production and processing of hydrocarbon streams: A perspective on key fundamentals, missing process data and economic feasibility – A review
PublikacjaThe present review emphasizes the role of hydrodynamic cavitation (HC) and acoustic cavitation in clean and green technologies for selected fuels (of hydrocarbon origins such as gasoline, naphtha, diesel, heavy oil, and crude oil) processing applications including biodiesel production. Herein, the role of cavitation reactors, their geometrical parameters, physicochemical properties of liquid media, liquid oxidants, catalyst loading,...
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Wastewater treatment by means of advanced oxidation processes based on cavitation – A review
PublikacjaHydrodynamic and acoustic cavitation combined with advanced oxidation processes (AOPs), including, among others, the Fenton process, is a promising alternative to the technologies of wastewater treatment technologies in use today. The present review discusses processes based on cavitation combined with AOPs and evaluates their effectiveness in oxidation of organic contaminants. Complete degradation of, among others, p-nitrotoluene,...
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Highly effective degradation of selected groups of organic compounds by cavitation based AOPs under basic pH conditions
PublikacjaCavitation has become on the most often applied methods in a number of industrial technologies. In the case of oxidation of organic pollutants occurring in the aqueous medium, cavitation forms the basis of numerous advanced oxidation processes (AOPs). This paper presents the results of investigations on the efficiency of oxidation of the following groups of organic compounds: organosulfur, nitro derivatives of benzene, BTEX, and...
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Cavitation Erosion Resistance Influence of Material Properties
PublikacjaThe 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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Cavitation-Based Processes for Water and Wastewater Treatment
PublikacjaCavitation 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-based technologies for pretreatment and processing of food wastes: Major applications and mechanisms – A review
PublikacjaConversion of food wastes to valuable products is an important topic for sustainable development. Feedstock hydrolysis is a stage strongly affecting the anaerobic digestion process, and resistance of food waste towards hydrolysis causes a decrease in product yield. Such as biomethane, biohydrogen, biohythane, VFAs, and lactic acids. Moreover, mass transfer is a serious limitation of transesterification for the production of biodiesel....
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Effective degradation of sulfide ions and organic sulfides in cavitation-based Advanced Oxidation Processes (AOPs)
PublikacjaThe paper presents the results of investigations on the effectiveness and reaction rate constants of the oxidation of sulfide ions and organic sulfides in real industrial effluents from the production of bitumens (2000 mg S2- L-1) using hydrodynamic and acoustic cavitation. The content of the effluents was analysed in terms carbon disulfide, dimethyl sulfide, and di-tert-butyl disulfide concentration. A possibility of complete...
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Design of horizontal axis wind and water turbines
PublikacjaThe basic hydrodynamic principles of horizontal axis turbines are presented. Computational methods based on vortex theory for design of such turbines and for calculation of their hydro or aerodynamic characteristics are described in detail. These methods are applicable both to wind and water turbines. The influence of detailed turbine geometry on its characteristics is presented. Several practical computational examples of different...
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Studies on Treatment of Bitumen Effluents by Means of Advanced Oxidation Processes (AOPs) in Basic pH Conditions
PublikacjaThe paper presents the results of studies on chemical treatment of effluents from production of bitumen of petroleum origin. Due to the presence of sulfide ions, the pH of these effluents is strongly alkaline. Several Advanced Oxidation Processes (AOPs) were studied, including the use of hydroxyl and sulfate radicals oxidants, the hydrodynamic cavitation as well as sonocavitation. The best processes allow to obtain 45% reduction...
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Studies on treatment of bitumen effluents by means of Advanced Oxidation Processes (AOPs) in basic pH conditions
PublikacjaThe paper presents the results of studies on chemical treatment of effluents from production of bitumen of petroleum origin. Due to the presence of sulfide ions, the pH of these effluents is strongly alkaline. Several Advanced Oxidation Processes (AOPs) were studied, including the use of hydroxyl and sulfate radicals oxidants, the hydrodynamic cavitation as well as sonocavitation. The best processes allow to obtain 45% reduction...
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Sample preparation procedure using extraction and derivatization of carboxylic acids from aqueous samples by means of deep eutectic solvents for gas chromatographic-mass spectrometric analysis
PublikacjaThe paper presents a new procedure for the determination of organic acids in a complex aqueous matrixusing ultrasound-assisted dispersive liquid–liquid microextraction followed by injection port derivati-zation and GC–MS analysis. A deep eutectic solvent (choline chloride: 4-methylphenol in a 1:2 mol ratio)was used both as an extracting solvent and as a derivatizing agent to yield ion pairs which were next con-verted to methyl...
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Ring thruster - a preliminary optimisation study
PublikacjaThe ring thruster is a new type of propeller, for which there is no experimental data to verify analytical design calculations. A significant feature of the ring thruster is the absence of a shaft. Propeller blades are mounted to the ring rotating inside the housing, which has the shape of a nozzle. For this reason the ring thruster is closest, with respect to both the construction and principle of operation, to the Kort nozzle...
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Bibliometric analysis and literature review of ultrasound-assisted degradation of organic pollutants
PublikacjaUltrasound as a clean, efficient, and cheap technique gains special attention in wastewater treatment. Ultrasound alone or coupled with hybrid processes have been widely studied for the treatment of pollutants in wastewater. Thus, it is essential to conduct a review about the research development and trends on this emerging technique. This work presents a bibliometric analysis of the topic associated with multiple tools such as...
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Towards Knowledge Formalization and Sharing in a Cognitive Vision Platform for Hazard Control (CVP-HC)
PublikacjaHazards are present in all workplaces and can result in serious injuries, short and long-term illnesses, or death. In this context, management of safety is essential to ensure the occupational health of workers. Aiming to assist the safety manage-ment process, especially in industrial environments, a Cognitive Vision Platform for Hazard Control (CVP-HC) has been proposed. The CVP-HC is a scalable yet adaptable system capable of...
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Cavitation Erosion – Phenomenon and Test Rigs
PublikacjaThe 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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Visual Content Learning in a Cognitive Vision Platform for Hazard Control (CVP-HC)
PublikacjaThis work is part of an effort for the development of a Cognitive Vision Platform for Hazard Control (CVP-HC) for applications in industrial workplaces, adaptable to a wide range of environments. The paper focuses on hazards resulted from the nonuse of personal protective equipment (PPE). Given the results of previous analysis of supervised techniques for the problem of classification of a few PPE (boots, hard hats, and gloves...
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Cavitation erosion degradation of Belzona® coatings
PublikacjaIn 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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Cavitation behavior of the SUPERSTON alloy after laser treatment
PublikacjaResults 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 Nodular Cast Iron - Microstructural Effects
PublikacjaThe 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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The resistance of S235JR steel to cavitation erosion
PublikacjaThe 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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Ruting w sieciach sensorowych typu ad hc
PublikacjaW artykule przedstawiono zagadnienia dotyczące rutingu w nowoczesnych sieciach sensorowych typu ad hoc.Omówiono tematykę rutingu w mobilnych sieciach komputerowych typu ad hoc (podział i opis najbardziej popularnych protokołów rutingu). Scharakteryzowano cechy sieci sensorowych ad hoc i wymagania jakie stawiają procesom rutingu. Przedstawiono czynniki wpływające na wydajność rutingu w nowoczesnej sieci czujników i oceniono przydatność...
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Cavitation wearing of the SUPERSTON alloy after laser treatment at cryogenic conditions
PublikacjaThe purpose of this paper is to demonstrate the method of laser remelting at cryogenic conditions of the SUPERSTON alloy and its influence on microstructure and cavitation wearing. The cavitation test was performed using the rotating disc facility in IPM PAN Gdansk. During the cavitation test, the mass loss of the material with different parameters of laser remelting was determined. Surface and cross-section microstructure of the...
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Cavitation Erosion of P110 Steel in Different Drilling Muds
PublikacjaThe 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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HYDRODYNAMIC THRUST BEARINGS WITH POLYMER LINING
PublikacjaPolymeric linings of sliding surfaces of the hydrodynamic bearings have been used successfully for over 50 years. Despite of their long history of operation and research, they have not become wide spread in industrial applications. This fact may be surprising, considering th e conclusions that have been published concerning bearing operation and design. This paper summarizes the current...
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Large Hydrodynamic Thrust Bearings and Their Application in Hydrogenerators
PublikacjaLarge hydrodynamic thrust bearings are the bearings which, due to hydrodynamic lubrication, allow large axial load to be transferred from a moving part (shaft) to the stationary part via a thin layer of the lubricant (usually oil), thus providing extremely low friction and practically no wear. Hydrogenerators with vertical shafts are the most important application of large thrust bearings. Main design and scientific problems of...
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Hydrodynamic Pressure Field of a Ship on Shallow Water
PublikacjaResults of calculations of the hydrodynamic pressure field around the ship were obtained by application of the boundary element method. Hydrodynamic field was calculated for a Polish Navy’s tugboat and transport ship using a program called SHiPP and compared with measurements of the field taken on river near Swinoujscie for two identical tugs H-4 and H-10. Next, a series of HPF calculations was carried out on planes situated at...
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Influence of Spatial Structures of 316L Stainless Steel on Its Cavitation Erosion Resistance
PublikacjaCavitation erosion performance of modified macroscopic internal structure 316L stainless steel was investigated. The samples processed by means of SLM method were subjected to cavitation erosion test. The scanning electron microscope Philips 30/ESEM was used to examine morphology of eroded surface.
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Large hydrodynamic thrust bearing: Comparison of the calculations and measurements
PublikacjaHydrodynamic thrust bearings, used to carry axial loads in heavily loaded shafts of water power plants hydro turbines, can reach outer diameters even exceeding 5 m. In such large objects scale effect could be observed. According to this, allowable bearing specific load assuring safe operation of the bearings has to be decreased, which increases thrust bearing dimensions. This effect is caused by excessive thermal deflections of...
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Cavitation Erosion Resistance of Austenitic Stainless Steel after Glow-Discharge Nitriding Process
PublikacjaThis paper presents investigation of cavitation erosion resistance of nitrided austenitic stainless steel X5CrNi18-10. The diffusion layers were produced by using different parameters of atmosphere (N2:H2). The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, glow-discharge optical emission spectrometer and X-ray diffractometry, respectively. Cavitation...
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Effect of Thermal Treatment and Erosion Aggressiveness on Resistance of S235JR Steel to Cavitation and Slurry
PublikacjaS235JR steel is used in many applications, but its resistance to the erosion processes has been poorly studied. To investigate this resistance, cavitation, and slurry erosion tests were conducted. These tests were carried out at different erosion intensities, i.e., different flow rates in the cavitation tunnel with a system of barricades and different rotational speeds in the slurry pot. The steel was tested as-received and after...
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Instantaneous impedance monitoring of synergistic effect between cavitation erosion and corrosion processes
PublikacjaThe most common method of determination of cavitation erosion resistance as well as the magnitude of erosion-corrosion synergistic interaction is based on the weight loss measurements. Nondestructive characterization of installations elements is in most cases impossible to perform. Also, such a measurement does not include local types of failure or alteration of operating conditions. There is an urge to elaborate a method for monitoring...
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DEVELOPMENT OF A COUPLED NUMERICAL AND EXPERIMENTAL APPROACH TO HYDRODYNAMIC NOISE ESTIMATION
PublikacjaThe hydroacoustic signature of ships' propellers can be estimated experimentally through measurements of cavitation-induced pressure fluctuations and the corresponding noise distributions at model scale. These measurements need to be performed in a cavitation tunnel under the propellers operating conditions and are quite sensitive and challenging to perform with sufficient accuracy. In comparison, the numerical approach can be...
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Effect of MAO coatings on cavitation erosion and tribological properties of 5056 and 7075 aluminum alloys
PublikacjaTwo ceramic coatings have been applied on 5056 and 7075 aluminum alloy by microarc oxidation (MAO) technology. The mass losses, surface morphologies and the phase constituents of the MAO coatings before and after cavitation tests were examined by means of digital scales, scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. In order to assess the impact of the mechanical properties of the surface layer on...