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Journal articles on the topic 'Cavitation facility'

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Published: 30 May 2022
Last updated: 31 May 2022

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1

Cervone, Angelo, Cristina Bramanti, Emilio Rapposelli, and Luca d’Agostino. "Thermal Cavitation Experiments on a NACA 0015 Hydrofoil." Journal of Fluids Engineering 128, no. 2 (September 13, 2005): 326–31. http://dx.doi.org/10.1115/1.2169808.

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The present paper illustrates the main results of an experimental campaign conducted in the Thermal Cavitation Tunnel of the Cavitating Pump Rotordynamic Test Facility (CPRTF) at Centrospazio/Alta S.p.A. Experiments were carried out on a NACA 0015 hydrofoil at various incidence angles, cavitation numbers, and freestream temperatures, in order to investigate the characteristics of cavitation instabilities and the impact of thermal cavitation effects. Measured cavity length, surface pressure coefficients, and unsteady pressure spectra are in good agreement with the data available in the open literature and suggest the existence of a strong correlation between the onset of the various forms of cavitation and instabilities, the thermal cavitation effects, and the effects induced by the presence of the walls of the tunnel. Further analytical investigations are planned in order to provide a better interpretation of the above results.
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2

Cervone, Angelo, Cristina Bramanti, Lucio Torre, Domenico Fotino, and Luca d’Agostino. "Setup of a High-Speed Optical System for the Characterization of Flow Instabilities Generated by Cavitation." Journal of Fluids Engineering 129, no. 7 (January 15, 2007): 877–85. http://dx.doi.org/10.1115/1.2742738.

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The present paper illustrates the setup and the preliminary results of an experimental investigation of cavitation flow instabilities carried out by means of a high-speed camera on a three-bladed inducer in the cavitating pump rotordynamic test facility (CPRTF) at Alta S.p.A. The brightness thresholding technique adopted for cavitation recognition is described and implemented in a semi-automatic algorithm. In order to test the capabilities of the algorithm, the mean frontal cavitating area has been computed under different operating conditions. The tip cavity length has also been evaluated as a function of time. Inlet pressure signal and video acquisitions have been synchronized in order to analyze possible cavitation fluid-dynamic instabilities both optically and by means of pressure fluctuation analysis. Fourier analysis showed the occurrence of a cavity length oscillation at a frequency of 14.7Hz, which corresponds to the frequency of the rotating stall instability detected by means of pressure oscillation analysis.
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3

DUTTWEILER, M. E., and C. E. BRENNEN. "Surge instability on a cavitating propeller." Journal of Fluid Mechanics 458 (May 10, 2002): 133–52. http://dx.doi.org/10.1017/s0022112002007784.

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This study details experiments investigating a previously unrecognized surge instability on a cavitating propeller in a water tunnel. The surge instability is explored through visual observation of the cavitation on the propeller blades and in the tip vortices. Similarities between the instability and previously documented cavitation phenomena are noted. Measurements of the radiated pressure are obtained, and the acoustic signature of the instability is identified. The magnitudes of the fluctuating pressures are very large, presumably capable of producing severe hull vibration on a ship.The origins of this instability are explored through separate investigation of the cavitation dynamics and the response of the water tunnel to volumetric displacement in the working section. Experiments are conducted to quantify the dynamics of the propeller cavitation. Finally, a model is developed for the complete system, incorporating both the cavitation and facility dynamics. The model predicts active system dynamics (linked to the mass flow gain factor familiar in the context of pump dynamics) and therefore potentially unstable behaviour for two distinct frequency ranges, one of which appears to be responsible for the instability.
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4

OKADA, Tsunenori, Yoshiro IWAI, and Hiroyuki MORl. "Cavitation bubble collapse pressures in a venturi facility." Transactions of the Japan Society of Mechanical Engineers Series B 55, no. 511 (1989): 579–84. http://dx.doi.org/10.1299/kikaib.55.579.

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5

Wan, Tao, Takashi Naoe, Hiroyuki Kogawa, Masatoshi Futakawa, Hironari Obayashi, and Toshinobu Sasa. "Numerical Study on the Potential of Cavitation Damage in a Lead–Bismuth Eutectic Spallation Target." Materials 12, no. 4 (February 25, 2019): 681. http://dx.doi.org/10.3390/ma12040681.

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To perform basic Research and Development for future Accelerator-driven Systems (ADSs), Japan Proton Accelerator Research Complex (J-PARC) will construct an ADS target test facility. A Lead–Bismuth Eutectic (LBE) spallation target will be installed in the target test facility and bombarded by pulsed proton beams (250 kW, 400 MeV, 25 Hz, and 0.5 ms pulse duration). To realize the LBE spallation target, cavitation damage due to pressure changes in the liquid metal should be determined, preliminarily, because such damage is considered to be very critical, from the viewpoint of target safety and lifetime. In this study, cavitation damage due to pressure waves caused by pulsed proton beam injection and turbulent liquid metal flow, were studied, numerically, from the viewpoint of single cavitation bubble dynamics. Specifically, the threshold of cavitation and effects of flow speed fluctuation on cavitation bubble dynamics, in an orifice structure, were investigated in the present work. The results showed that the LBE spallation target did not undergo cavitation damage, under normal nominal operation conditions, mainly because of the long pulse duration of the pulsed proton beam and the low liquid metal flow velocity. Nevertheless, the possibility of cavitation damage in the orifice structure, under certain extreme transient LBE flow conditions, cannot be neglected.
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6

Majkowska, Beata, and Waldemar Serbiński. "Cavitation Wearing of the SUPERSTON Alloy after Laser Treatment at Cryogenic Conditions." Solid State Phenomena 165 (June 2010): 306–9. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.306.

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The 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 SUPERSTON alloy after laser treatment and cavitation test were observed by scanning electron microscope. The cavitation resistance of the remelted SUPERSTON alloy was approximately 40% higher in comparison to the base material.
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7

Wetzel, J. M., and R. E. A. Arndt. "Hydrodynamic Design Considerations for Hydroacoustic Facilities: Part II—Pump Design Factors." Journal of Fluids Engineering 116, no. 2 (June 1, 1994): 332–37. http://dx.doi.org/10.1115/1.2910276.

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The St. Anthony Falls Hydraulic Laboratory has been involved in the hydrodynamic design of large cavitation facilities, which require a high performance axial flow pump that is cavitation free to meet stringent design conditions. As cavitation has been shown to be the largest noise source in an otherwise well designed facility, it must be eliminated for the design range of flow conditions. To reduce the possibility of blade cavitation it is desirable to have a near uniform, or at least, a near symmetrical approach velocity distribution at the pump inlet. The design of flow facilities to achieve such an inflow was the subject of extensive investigations. These investigations consisted of both numerical and physical modeling of critical components in the test loop. The influence of these components, which included the contraction, diffuser, and turning vanes was carefully documented. The combination of the two modeling techniques will be demonstrated as an effective design tool for a high performance, hydrodynamic test facility.
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8

Szkodo, Marek. "Influence of Cavitation Intensity on the Relative Cavitation Resistance of Laser Processed C45 Carbon Steel." Solid State Phenomena 165 (June 2010): 189–94. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.189.

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This work presents investigations of relative cavitation resistance of carbon steel (C45) at the initial stage of erosion, after melting its surface by 6 kW CO2 laser beam. The research work was carried out on the rotating disk facility. Three areas were determined on the surface of investigated sample. Each area was eroded with different intensity. The procedures were elaborated for calculation of resistance of processed surface to plastic deformation under cavitation loading and of relative intensity of cavitation using image analysis of monochromatic picture of eroded surface. The results indicate that increase of cavitation loading intensity results in decrease of relative cavitation resistance.
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9

Manzana, Madalina Elena, Brandusa Ghiban, Ilare Bordeaşu, Nicolae Ghiban, Mihai Marin, and Florin Miculescu. "Structural Analysis of Steels by Cavitation Erosion." Key Engineering Materials 583 (September 2013): 28–31. http://dx.doi.org/10.4028/www.scientific.net/kem.583.28.

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Cavitation is an important factor in many areas of science and engineering, including acoustics, chemistry and hydraulics. In this paper the authors analyze the structural analysis of cavitation damages in two steel. The cavitation erosion tests were carried out in a magnetostrictive facility, in Timisoara Hydraulic Machinery Laboratory, in according with ASTM G32-85, using as cavitant liquid drink water at 20 10C. After quantitative and qualitative investigations structural features were put in evidence on experimental steel
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10

Coutier-Delgosha, O., A. Dazin, G. Caignaert, and G. Bois. "Analysis of Cavitation Instabilities in a Four-Blade Inducer." International Journal of Rotating Machinery 2012 (2012): 1–11. http://dx.doi.org/10.1155/2012/213907.

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The cavitating behavior of a four-blade inducer tested in the LML laboratory large test facility is considered in the present paper. Experimental investigations based on unsteady pressure measurements and records from a six-component balance mounted on the inducer shaft are performed. Spectral analysis of the signals enables to detect several characteristic frequencies related to unbalanced two-phase flow patterns. The objective of the present paper is the understanding of the physical phenomena associated to these frequencies. Therefore, wavelet decomposition, flow visualizations, and direct analysis of the high-frequency force, moment, and pressure signals are applied. Results at nominal flow rate only are considered. Not only classical unbalanced cavitation patterns, but also unexpected flow organizations are discussed.
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11

Szkodo, Marek, Artur Sitko, and Maria Gazda. "Cavitation Erosion Resistance of Austenitic Stainless Steel after Glow-Discharge Nitriding Process." Solid State Phenomena 183 (December 2011): 201–6. http://dx.doi.org/10.4028/www.scientific.net/ssp.183.201.

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This paper presents investigation of cavitation erosion resistance of nitrided austenitic stainless steel X5CrNi18-10. The diffusion layers were produced by using different parameters of reactive 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 erosion resistance of produced surface layers was investigated in a rotating disc facility. As a property characterizing the cavitation erosion resistance of manufactured surface layers were proposed incubation period and mass loss after 330 min of cavitation test. It was found that cavitation erosion resistance of modified surface layers is lower than reference material (not treated X5CrNi18-10 stainless steel).
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12

Chmiel, Jarosław, and Ellina Łunarska. "Role of Hydrogen in Cavitation Degradation of Iron in Water Solutions." Solid State Phenomena 225 (December 2014): 59–64. http://dx.doi.org/10.4028/www.scientific.net/ssp.225.59.

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Hydrogen ingress into a metal has been observed at cavitation in distilled water and in 3% NaCl solution at open circuit potential. The measurements of hydrogen permeation rate have been made using an ultrasonic cavitation facility with an attached Devanathan-Stachurski double cell. Increase in vibration amplitude has been associated with the increase in amplitude of electrochemical voltage and current pulses and with the modification of hydrogen permeation rate. Hydrogen behavior within the metal has been affected by the cavitation induced dynamic stresses and metal deformation hardening, ascertained on the basis of the appearance of hydrogen permeation transients at cavitation in comparison with those recorded for the unstressed state. Metal damage has been a resultof associated effects of cavitation and hydrogen.
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13

Chmiel, Jarosław, and Ellina Lunarska. "Effect of Cavitation on Absorption and Transport of Hydrogen in Iron." Solid State Phenomena 183 (December 2011): 25–30. http://dx.doi.org/10.4028/www.scientific.net/ssp.183.25.

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Using the specially designed ultrasonic cavitation facility enabling to measure the hydrogen permeation, the experimental evidence have been provided for hydrogen to ingress in the metal subjected to cavitation in the 3% NaCl solution under the open circuit conditions. Increase in the vibration amplitude resulted in the increase in amplitude of the electrochemical voltage and current pulses and in the hydrogen permeation rate, as well. The cavitation induced modification of hydrogen transport through the membrane has been stated on the base of different appearance of the hydrogen permeation transients at cavitation in comparison with those recorded for the unstressed membrane. The hydrogen behavior has been affected by the cavitation induced dynamic stresses, metal hardening and stress relaxation due to microcracking of the metal.
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14

Somia Alfatih, M. S., M. Salman Leong, and L. M. Hee. "Experimental Investigation on the Use of Bispectral Analysis in Detecting Nonlinear Faults in Hydraulic Machines." Applied Mechanics and Materials 606 (August 2014): 147–51. http://dx.doi.org/10.4028/www.scientific.net/amm.606.147.

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Bispectral analysis is one of the relatively more recent tools in signal processing used for detection and identification of higher harmonics in a signal. It is also acknowledged to be one of Higher Order Spectral Analysis (HOSA) effective tools for detecting nonlinear behavior in mechanical systems. In this study, vibration sources in a hydraulic machine which may have features of nonlinear behavior were investigated. An experimental study was undertaken to formulate a more sensitive and effective method using Bispectral analysis to diagnose cavitation in a centrifugal pump facility. Cavitation was induced on the suction side of the pump. The cavitation signal was analyzed with and without induced cavitation conditions at different locations on the pump, and analyzed using FFT and bispectrum methods. It was observed that bispectral analysis could be used as an early indicator of cavitation with changes for severity of cavitation.
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15

Szkodo, Marek. "Cavitation Erosion Resistance of Austenitic Microstructure Created by Laser Beam." Solid State Phenomena 165 (June 2010): 195–200. http://dx.doi.org/10.4028/www.scientific.net/ssp.165.195.

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This work presents investigations of cavitation properties of different austenitic microstructures formed by laser beam machining of X5CrNi18-10 and C45 steels. X5CrNi18-10 steel was alloyed with TiC and Mn powders and surface layer of C45 steel was enriched with Ni, Mn, Cr and Nb. For alloying the cw CO2 laser beam was used as a power source. Cavitation behaviour of produced layers was investigated in a rotating disc facility. The results reveal different susceptibility to plastic deformation and strain hardening degree of surface in the early stage of cavitation erosion.
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16

Zhang, Chun Hua, Ning Yan, Yu Xi Hao, Chao Wang, Xu Bian, and Song Zhang. "Study on Cavitation Erosion Behavior of Monel Alloys in the Simulated Seawater Solution." Advanced Materials Research 631-632 (January 2013): 40–43. http://dx.doi.org/10.4028/www.scientific.net/amr.631-632.40.

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Cavitation erosion test of Monel-400 and MonelK-500 alloys was carried out in 3.5% NaCl solution using an ultrasonic induced cavitation facility. The microstructure, composition and mechanism of cavitation erosion were analyzed by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and induction balance, respectively. The results showed that Monel-400 alloy was single austenitic phase while MonelK-500 alloy contained Ni3Al intermetallics and its improvement in cavitation erosion resistance could be attributed to the higher hardness and density of the grain and twinning boundaries. In a series of 5h cavitation tests, the cumulative mass loss of Monel-400 alloy was 44.5 mg, which was 1.66 times than that of MonelK-500(26.8mg). No apparent incubation period was observed and the damage mechanism was plastic deformation and rupture.
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17

Szkodo, Marek. "Cavitation Erosion Behavior of 18/8 Stainless Steel after Its Laser Alloying of Manganese." Solid State Phenomena 113 (June 2006): 513–16. http://dx.doi.org/10.4028/www.scientific.net/ssp.113.513.

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The laser surface alloying of 18/8 stainless steel with Mn, was carried out by 6 kW cw CO2 laser. The microstructure, chemical composition and phase identification of the modified layer were examined using scanning electron microscopy, energy dispersive X-ray spectroscopy and Xray diffractometry, respectively. Cavitation behavior of produced layers was investigated in a rotating disc facility. Cavitation properties of laser-processed steel were calculated in the initial stage of erosion, on the surface of about 4 mm2, on which cavitation intensity was constant. As a property characterizing the cavitation erosion resistance of materials was proposed for the depth of strain hardening. It was found that presence of manganese in the amount of 7.31% causes the highest increase hardness after alloying and the lowest depth of strain hardening due to cavitation loading.
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18

Xing, Wen Jing. "Microstructure of Copper Alloy Effects on Cavitation Damage." Advanced Materials Research 239-242 (May 2011): 575–79. http://dx.doi.org/10.4028/www.scientific.net/amr.239-242.575.

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The cavitation erosion behavior of ZQAl9-4-4-2 nickel-alum inium bronze in 2.4%NaCl solution was investigated by using a magnetostrictive – induced cavitation facility. The micrographs of damaged surface were observed by scanning electron microscope (SEM) and transmission electron microscopy(TEM). The results showed that the cavitation microcrack in the a phase adjacent to the k phase. They propagated and connected with each other in the a phases, resulted in the removal of a phases and detachment of the kphase from the matrix in the following test period followed. The microcracks tended to propagate parallelly to the eroded surfaces.
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19

OKADA, Tsunenori, Yoshiro IWAI, and Hiroyuki MORI. "An approach to studying cavitation erosion in the venturi facility." Transactions of the Japan Society of Mechanical Engineers Series A 56, no. 523 (1990): 431–36. http://dx.doi.org/10.1299/kikaia.56.431.

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20

Wang, Xiaoyu, Haofeng Wang, Jingchao Zhao, Shenghao Zhou, Zhong Luo, and Qingkai Han. "Evaluation of Liner Cavitation Potential through Piston Slap and BEM Acoustics Coupled Analysis." Mathematics 10, no. 6 (March 8, 2022): 853. http://dx.doi.org/10.3390/math10060853.

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Internal combustion engines take up the major position in the power facility market and still encounter some challenges; one key issue is liner cavitation erosion. The impact vibration between piston and cylinder generates pressure fluctuation on the wet liner surface and leads to the occurrence of cavitation in the case that coolant pressure falls below its vapor pressure. Piston slap methodology has been improved by considering the dynamic characteristics of the piston. Water coolant passage acoustic features were investigated and the Helmholtz effect between cylinders was confirmed. In order to address the cavitation erosion potential of the engine cylinder, acoustic pressure in the cooling water passage was investigated by boundary element method analysis with the acceleration of the cylinder liner which was obtained from the piston slap program. This study revealed that a certain acoustic mode of the cooling water passage had a dominant effect on the amplitude of water coolant dynamic pressure induced by liner vibration. Measures of eliminating the acoustic mode are believed to be able to suspend pressure fluctuation and furthermore the potential of cavitation.
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21

Kosty, M. P., P. Kumar, A. Wozniak, M. Jahanzeb, C. Chung, L. Wang, A. Sing, and T. Lynch. "Development of cavitation while on bevacizumab (BV) therapy in patients (pts) with non-small cell lung cancer (NSCLC): Results from ARIES—A bevacizumab (BV) treatment observational cohort study (OCS)." Journal of Clinical Oncology 27, no. 15_suppl (May 20, 2009): e19045-e19045. http://dx.doi.org/10.1200/jco.2009.27.15_suppl.e19045.

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e19045 Background: BV (Avastin), an anti-VEGF monoclonal antibody, prolongs progression-free and overall survival in advanced NSCLC pts. Severe (≥grade 3) pulmonary hemorrhage (sPH) is a rare but serious event that has been associated with BV-based therapy in phase 3 trials (rate of 2–4%). Potential risk factors include squamous histology, prior history of hemoptysis, and presence of tumor cavitation. Rates of baseline (BL) cavitation in NSCLC pts and development of cavitation on BV therapy are unknown. Pts in ARIES, an OCS of approximately 2,000 pts with NSCLC, had BL scans assessed for tumor cavitation. A substudy of approximately 250 pts also had follow-up scans to analyze the likelihood of developing cavitation on BV therapy. For the entire ARIES population, any pt developing sPH is assessed for tumor cavitation. Methods: Pts at specified ARIES sites submitted on-treatment CT scans to an independent review facility (IRF), in addition to BL scans. Evaluable pts had measurable disease at BL and at least one-post-BL scan. Correlations between cavitation (pre-existing or developing on-study) and clinical, tumor and treatment characteristics are evaluated using a chi-squared test or t-test. Incidence of sPH based on cavitation status will be assessed using Fisher's exact test. Results: As of 9/15/08, 210 pts had a post-BL CT scan reviewed by the IRF. Of these pts, 171 had measurable tumors at BL. For the 171 pt cohort: median F/U is 9.2 m; 99% have ≥1 quarterly update. Key BL characteristics for the substudy and overall cohorts, respectively, include: 44% vs 51% ≥65 yrs; 67% vs 67% adenocarcinoma; 6% vs 5% therapeutic AC. BL radiographic features: 41% vs 39% presence of central tumor; 13% vs 15% presence of cavitation. In substudy pts, there is 1 sPH to date in a pt without baseline cavitation. Conclusions: sPH is a rare, potentially serious event in pts with NSCLC receiving BV. Whether cavitation (BL or developing on-treatment) is associated with an increased risk of sPH has not been defined. The final analysis of an ARIES Lung substudy assessing on-study development of cavitation and association with sPH will be presented at the meeting. [Table: see text]
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22

Yonezawa, Koichi, Daisuke Konishi, Kazuyoshi Miyagawa, Francois Avellan, Peter Doerfler, and Yoshinobu Tsujimoto. "Cavitation Surge in a Small Model Test Facility simulating a Hydraulic Power Plant." International Journal of Fluid Machinery and Systems 5, no. 4 (December 31, 2012): 152–60. http://dx.doi.org/10.5293/ijfms.2012.5.4.152.

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23

Kondo, Hiroo, Takuji Kanemura, Tomohiro Furukawa, Yasushi Hirakawa, and Eiichi Wakai. "ICONE23-1110 MEASUREMENT OF CAVITATION IN A DOWNSTREAM CONDUIT OF THE LIQUID LITHIUM TARGET FOR INTERNATIONAL FUSION MATERIALS IRRADIATION FACILITY." Proceedings of the International Conference on Nuclear Engineering (ICONE) 2015.23 (2015): _ICONE23–1—_ICONE23–1. http://dx.doi.org/10.1299/jsmeicone.2015.23._icone23-1_59.

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24

Futakawa, Masatoshi. "Proton Bombardment in Mercury Target for Neutron Production - Impact Dynamics on Interface between Liquid and Solid Metals." Applied Mechanics and Materials 566 (June 2014): 26–33. http://dx.doi.org/10.4028/www.scientific.net/amm.566.26.

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Innovative researches using neutrons are being performed at the Materials & Life Science Experimental Facility (MLF) in the Japan Proton Accelerator Research Complex (J-PARC), in which a mercury target system is installed as MW-class pulse spallation neutron sources. In order to produce neutrons by the spallation reaction, proton beams are injected into the mercury target. At the moment when the intense proton beam hits the target, pressure waves are generated in mercury because of abrupt heat deposition. The pressure waves interact with the target vessel leading to negative pressure that may cause cavitation along the vessel wall, i.e. the interface between liquid and solid metals. Localized impacts by microjets and/or shock waves that are caused by cavitation bubble collapse impose pitting damage on the vessel wall. The pitting damage that degrades the structural integrity of the target vessel is a crucial issue for the high power mercury targets. Therefore, the mitigation techniques for the pitting damages and cavitation are needed to reach the MW-class pulsed spallation neutron sources.
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Poussou, Stephane, and Michael W. Plesniak. "Near-Field Flow Measurements of a Cavitating Jet Emanating From a Crown-Shaped Nozzle." Journal of Fluids Engineering 129, no. 5 (October 30, 2006): 605–12. http://dx.doi.org/10.1115/1.2717615.

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The effect of a crown-shaped nozzle on cavitation is studied experimentally in the near-field of a 25 mm diameter (D) water jet at ReD=2×105 using particle image velocimetry (PIV) and high speed shadowgraphy recorded with a 5000 fps digital camera. The objectives are to passively control the jet flow structure and to examine its consequences on the physical appearance of cavitating bubbles. The experiments are performed in a closed-loop facility that enables complete optical access to the near-nozzle region. The cavitating and noncavitating mean velocity fields are obtained up to three nozzle diameters downstream and compared to those of a companion round nozzle. PIV measurements are taken in two distinct azimuthal planes passing through the tip and bottom points of the crown nozzle edge. The data include shear layer momentum thickness and vorticity thickness, spanwise vorticity distribution and streamwise normal Reynolds stress. Significant deviation from an axisymmetric shear layer is observed in the noncavitating flow consistently up to one diameter downstream, after which identical asymptotic conditions are achieved in both round and crown-shaped nozzles. Maximum magnitudes of spanwise vorticity and streamwise normal Reynolds stress are the highest downstream of the nozzle tip edges under noncavitating conditions. Significant modifications in trends and magnitudes are observed for the shear layer momentum thickness under cavitating conditions up to one diameter downstream. Qualitative flow visualization reveals that bubble growth occurs at different conditions depending on azimuthal location. Bubbles, in the form of elongated filaments, are the dominant structures produced downstream of the valley edges of the nozzle with an inclination of 45 deg with respect to the direction of the flow, and are observed to persist with significant strength up to two diameters downstream. These filaments are stretched between periodic larger-scale, spanwise bubbly clusters distorted in the shape of the nozzle outlet. The tip edges produce cavitating bubbles under conditions similar to that of a classical round nozzle. In summary, it was demonstrated that passive control of turbulent structures in the jet does impact the cavitation process.
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Wang, Chuangnan, Thomas Connolley, Iakovos Tzanakis, Dmitry Eskin, and Jiawei Mi. "Characterization of Ultrasonic Bubble Clouds in A Liquid Metal by Synchrotron X-ray High Speed Imaging and Statistical Analysis." Materials 13, no. 1 (December 20, 2019): 44. http://dx.doi.org/10.3390/ma13010044.

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Quantitative understanding of the interactions of ultrasonic waves with liquid and solidifying metals is essential for developing optimal processing strategies for ultrasound processing of metal alloys in the solidification processes. In this research, we used the synchrotron X-ray high-speed imaging facility at Beamline I12 of the Diamond Light Source, UK to study the dynamics of ultrasonic bubbles in a liquid Sn-30wt%Cu alloy. A new method based on the X-ray attenuation for a white X-ray beam was developed to extract quantitative information about the bubble clouds in the chaotic and quasi-static cavitation regions. Statistical analyses were made on the bubble size distribution, and velocity distribution. Such rich statistical data provide more quantitative information about the characteristics of ultrasonic bubble clouds and cavitation in opaque, high-temperature liquid metals.
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27

Zheng, Xueyu, Luchen Zhang, Shiqiang Wu, and Kai Song. "Study on the Shape of the Aerator of High-Head Discharge Tunnel with Mild Bottom Slope." Water 13, no. 15 (August 2, 2021): 2128. http://dx.doi.org/10.3390/w13152128.

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Due to the high flow velocity and easy cavitation of high-head drainage tunnels, it is usually necessary to set up aeration facilities. In particular, when the bottom slope of the tunnel is mild, the aeration facilities often have problems such as difficulty with air intake, short cavity, and serious water accumulation, which aggravate the risk of cavitation damage. In this paper, based on the Rumei hydropower station and the Gushui hydropower station, a method combining theoretical analysis and model testing is used to solve the connection problem between the aeration facility and the 3% mild bottom slope of a tunnel body, and the aeration facility shape of “lifting ridge + flat (mild) slope + steep slope” is put forward. The research shows that the steep slope section can smoothly connect the water flow over the cantilever, reduce the jet impact angle, prevent the water from backtracking, and produce a long and stable cavity in the flat (mild) slope section. The aeration concentration along the bottom of the tunnel is higher than 3% at 140 m over the top of the dam. The aeration effect of this type is better, and it can provide effective long-distance protection for a drainage tunnel with high head and a mild bottom slope.
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28

Bordeasu, I., M. O. Popoviciu, V. Balasoiu, A. D. Jurchela, and A. Karabenciov. "Influence of the vibratory test facility type and parameters upon the cavitation erosion evolution." IOP Conference Series: Earth and Environmental Science 12 (August 1, 2010): 012037. http://dx.doi.org/10.1088/1755-1315/12/1/012037.

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Sakai, Kento, Bungo Iwase, Keisuke Matsumoto, Kazuyoshi Miyagawa, and Satoshi Kawasaki. "Investigation on axial thrust behavior of balance piston system for a rocket pump." Journal of Physics: Conference Series 2217, no. 1 (April 1, 2022): 012029. http://dx.doi.org/10.1088/1742-6596/2217/1/012029.

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Abstract High stability in axial direction is required for rocket pumps operated under extremely low-temperature and high-pressure conditions, turbopumps therefore uses balance piston (BP) system for balancing their axial thrust. The BP system is stable under quasi-static conditions. However, BP system might become dynamically unstable under some condition. Thus it is fundamental for stability evaluation of turbopumps to predict static/dynamic characteristics in axial direction of BP system. Furthermore, we focus on characteristic change by cavitation which often occurs in the pump inlet. In this paper, an experimental study of a model turbopump which had an unshrouded impeller equipped with BP system was carried out. We experimented it with an active magnetic bearing (AMB) test facility in order forcibly to oscillate it with an optional amplitude and frequency. In addition, we examined characteristics of BP system by three-dimensional computational fluid dynamics (3D-CFD) simulations. The results of 3D-CFD simulations were in good agreement with these tendency of BP system, and were effective in predicting its static/dynamic characteristics. Some cases showed that dynamic characteristic of BP system became unstable by growth of cavitation, therefore we suggest that the influence of cavitation must also be considered in the design of turbopump.
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30

NANRI, Hideaki, Hiroki KANNAN, Naoki TANI, and Yoshiki YOSHIDA. "199 One-dimensional Analysis of Cavitation Surge on Rocket Engine Turbopump Test Facility Considering the Acoustic Effect : 2nd report : Effect of Accumulator on Cavitation Surge." Proceedings of Conference of Tohoku Branch 2010.45 (2010): 198–99. http://dx.doi.org/10.1299/jsmeth.2010.45.198.

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31

Kikuchi, Kinya, and Frederick G. Hammitt. "Effect of separation distance on cavitation erosion of vibratory and stationary specimens in a vibratory facility." Wear 102, no. 3 (April 1985): 211–25. http://dx.doi.org/10.1016/0043-1648(85)90219-4.

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32

NANRI, Hideaki, Hiroki KANNAN, Naoki NAGAO, and Yoshiki YOSHIDA. "1116 One-dimensional Analysis of Cavitation Surge on Rocket Engine Turbopump Test Facility Considering the Acoustic Effect." Proceedings of the Fluids engineering conference 2009 (2009): 373–74. http://dx.doi.org/10.1299/jsmefed.2009.373.

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33

Iwai, Y., T. Okada, and H. Mori. "A study of cavitation bubble collapse pressures and erosion part 3: the results in a venturi facility." Wear 150, no. 1-2 (October 1991): 367–78. http://dx.doi.org/10.1016/0043-1648(91)90330-w.

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34

Mimouni, Stephane, William Benguigui, Solène Fleau, Arnaud Foissac, Mathieu Guingo, Mickael Hassanaly, Jérôme Lavieville, et al. "Dispersed Two-Phase Flow Modelling for Nuclear Safety in the NEPTUNE_CFD Code." Science and Technology of Nuclear Installations 2017 (2017): 1–41. http://dx.doi.org/10.1155/2017/3238545.

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The objective of this paper is to give an overview of the capabilities of Eulerian bifluid approach to meet the needs of studies for nuclear safety regarding hydrogen risk, boiling crisis, and pipes and valves maintenance. The Eulerian bifluid approach has been implemented in a CFD code named NEPTUNE_CFD. NEPTUNE_CFD is a three-dimensional multifluid code developed especially for nuclear reactor applications by EDF, CEA, AREVA, and IRSN. The first set of models is dedicated to wall vapor condensation and spray modelling. Moreover, boiling crisis remains a major limiting phenomenon for the analysis of operation and safety of both nuclear reactors and conventional thermal power systems. The paper aims at presenting the generalization of the previous DNB model and its validation against 1500 validation cases. The modelling and the numerical simulation of cavitation phenomena are of relevant interest in many industrial applications, especially regarding pipes and valves maintenance where cavitating flows are responsible for harmful acoustics effects. In the last section, models are validated against experimental data of pressure profiles and void fraction visualisations obtained downstream of an orifice with the EPOCA facility (EDF R&D). Finally, a multifield approach is presented as an efficient tool to run all models together.
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35

Cui, Kai Bo, Jun Qi Qin, Chang Chun Di, and Yu Liang Yang. "The Wear Mechanism Analysis for the Surface of Aluminum Brass in Recoil Brake." Advanced Materials Research 773 (September 2013): 402–5. http://dx.doi.org/10.4028/www.scientific.net/amr.773.402.

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To study the malfunction cause and wear mechanism of aluminum brass in gun recoil brake, based on microscopic analysis technology, scrapped throttling ring from the repair facility as research objects, the throttling ring wear mechanism is analyzed systematically from the microscopic point integrated use of metallurgical microscope analysis, scanning electron microscopy and energy dispersive spectrometer analysis. Studies show that, as one of the vital components in recoil brake, the throttling ring made of aluminum brass is due to the composite role of erosive abrasion, chemical corrosion and cavitation damage leading to failure. The method can provide reference for the improvement of the throttling ring and the failure analysis of similar alloy parts.
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36

Loughrin, John, Stacy Antle, Michael Bryant, Zachary Berry, and Nanh Lovanh. "Evaluation of Microaeration and Sound to Increase Biogas Production from Poultry Litter." Environments 7, no. 8 (August 16, 2020): 62. http://dx.doi.org/10.3390/environments7080062.

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Microaeration, wherein small amounts of air are introduced into otherwise anaerobic digesters, has been shown to enhance biogas production. This occurs by fostering the growth of facultatively aerobic bacteria and production of enzymes that enhance the degradation of complex polymers such as cellulose. The treatment of anaerobic digestate with sound at sonic frequencies (<20 kHz) has also been shown to improve biogas production. Microaeration at a rate of 800 mL day−1, treatment with a 1000-Hz sine wave, and combined microaeration/sound were compared to a control digester for the production of biogas and their effect on wastewater quality. Poultry litter from a facility using wood chips as bedding was used as feed. The initial feeding rate was 400 g week−1, and this was slowly increased to a final rate of 2400 g week−1. Compared to the control, sound treatment, aeration, and combined sound/aeration produced 17%, 32%, and 28% more biogas. The aeration alone treatment may have been more effective than combined aeration/sound due to the sound interfering with retention of aeration or the formation of free radicals during cavitation. Digesters treated with sound had the highest concentrations of suspended solids, likely due to cavitation occurring within the sludge and the resulting suspension of fine particles by bubbles.
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37

NANRI, Hideaki, Naoki TANI, Hiroki KANNAN, and Yoshiki YOSHIDA. "J0501-4-1 One-dimensional Analysis of Cavitation Surge on Rocket Engine Turbopump Test Facility Considering the Acoustic Effect : 3rd Report, Effect of a Frequency Response of Cavitation Characteristics." Proceedings of the JSME annual meeting 2010.7 (2010): 37–38. http://dx.doi.org/10.1299/jsmemecjo.2010.7.0_37.

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38

Xu, Yi Min, Hong Xuan Yang, Wei Zhao, and Chun Ying Shen. "Study on the Air Pressure and the Backwater in the Cavity of Aerator on the Chute with an Anti-Arc Section." Advanced Materials Research 446-449 (January 2012): 2740–44. http://dx.doi.org/10.4028/www.scientific.net/amr.446-449.2740.

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Aeration facility is widely used to reduce cavitation erosion of discharge works caused by high speed flows and it has proved to be an economical, effective and successful measure. For a flow chute with complex boundary conditions, the air pressure and backwater in an aerator cavity are important factors that influence the flow aeration, and there are numerous and complex hydraulic factors to affect them. By the jet trajectory equation and a series of experimental tests, the air pressure and backwater in different aerator cavities are investigated. How these factors such as the size and style of aerator, the arc radius of the chute and flow discharge to influence the air pressure and backwater in an aerator cavity are revealed. These results can be referenced in designing aerators on the chute with a concave surface.
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39

Nanjo, H., A. Shima, and T. Tsujino. "Cavity Cloud Formation and Generation of Stringy Damage Patterns in a Polymer Solution." Proceedings of the Institution of Mechanical Engineers, Part C: Journal of Mechanical Engineering Science 202, no. 4 (July 1988): 263–67. http://dx.doi.org/10.1243/pime_proc_1988_202_118_02.

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Cavity cloud formation and generation of stringy damage patterns on an aluminium specimen in a polymer solution were studied using a vibratory cavitation facility. It is shown that few bubbles are seen on a specimen although numerous bubbles appear at a place several millimetres away from the specimen. Since a polymer solution may behave elastically due to the relaxation effect, the solution can follow the vibration of the specimen. Therefore the pressure on the specimen in the polymer solution does not fall to as great an extent as in water, and so consequently fewer bubbles form. Stringy damage patterns originate from cracks on the specimen surface or impurities in the polymer solution adjacent to the specimen. It is also shown that the addition of polymer greatly affected the damage rate.
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40

Babu, P. V. Thangam, and D. V. Reddy. "Dynamic Coupled Fluid-Structure Interaction Analysis of Flexible Floating Platforms." Journal of Energy Resources Technology 108, no. 4 (December 1, 1986): 297–304. http://dx.doi.org/10.1115/1.3231280.

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The paper presents the dynamic response analysis of a flexible floating platform subjected to water transmitted, amplified earthquake accelerations input at its base. The finite element method is used for formulating the unsymmetric, coupled dynamic equations of equilibrium of the fluid-structure continuum. The boundary conditions include the free surface wave and radiation damping. The amplification of the earthquake through the water medium is studied using a linear system of lumped masses, springs, and dashpots. A new procedure is demonstrated to solve the coupled, unsymmetric equations using a specially developed computer program FLUSIN. Depending on the water depth, it is estimated that the vertical accelerations transmitted to the bottom of the floating structure may be amplified considerably. Cavitation is a possibility for greater depths and higher accelerations. Two numerical illustrations are presented—a floating nuclear plant and a liquid petroleum gas storage facility subjected to amplitude earthquake accelerations. The results compare well with those obtained by other investigators using approximate techniques. The procedure can be applied to floating exploration/production-storage/transportation platforms and pipelaying barges subjected to water transmitted earthquake forces. The formulation is easily adaptable to any fluid-structure system as well as for other kinds of dynamic excitation. With the increased focusing of attention to compliant-type tension-legged platforms and semisubmersibles for production/drilling and LPG storage platforms, the project is of considerable significance. The work is a forerunner for much needed experimental investigation, particularly with respect to cavitation. Also, the findings would have considerable spin-off effects to OTEC concepts.
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41

Sandler, Alan B., Joan H. Schiller, Robert Gray, Isaiah Dimery, Julie Brahmer, Meghna Samant, Lisa I. Wang, and David H. Johnson. "Retrospective Evaluation of the Clinical and Radiographic Risk Factors Associated With Severe Pulmonary Hemorrhage in First-Line Advanced, Unresectable Non–Small-Cell Lung Cancer Treated With Carboplatin and Paclitaxel Plus Bevacizumab." Journal of Clinical Oncology 27, no. 9 (March 20, 2009): 1405–12. http://dx.doi.org/10.1200/jco.2008.16.2412.

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PurposeSevere (grade ≥ 3) pulmonary hemorrhage (PH) in advanced non–small-cell lung cancer was observed in two prospective, randomized, phase II (N = 99) and phase III (N = 878) trials of bevacizumab plus carboplatin and paclitaxel. Retrospective case-control and cohort analyses were conducted to identify associated radiographic and clinical risk factors for PH.Patients and MethodsSix patients with PH from the phase II trial, 15 potential PH patients with hemorrhage at any site from the phase III trial, and their matched controls were evaluated with review of baseline and on-treatment radiographs by an independent radiology facility, blinded to patient/control status. Patients with severe (grade ≥ 3) PH from each trial were matched with up to three controls based on sex, age group, histology (phase II), or sex and age group (phase III).ResultsSeven PH patients in the phase III trial were identified as severe PH. Six of the patients were early onset (occurred < 150 days of initiating bevacizumab) and one was late onset. Baseline tumor cavitation, not tumor location, was identified as the only potential risk factor for patients with early onset. Combined analysis of severe PH patients from the phase II and phase III trials (n = 13), compared with their pooled matched controls (n = 42), did not identify any additional baseline radiographic or clinical variables associated with PH.ConclusionPH was an uncommon event. Based on these analyses, baseline tumor cavitation may be a potential risk factor for PH. No other baseline clinical variables were predictive for PH although the number of events was small.
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42

Stanciu, Ion Rares, Gheorghita Ginga, Sebastian Muntean, and Liviu Eugen Anton. "A Multi-Purpose Vision-Equipped-Remotely-Operable Rig for Hydro-Units Monitoring." Advanced Engineering Forum 8-9 (June 2013): 175–84. http://dx.doi.org/10.4028/www.scientific.net/aef.8-9.175.

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Hydroelectricity is a viable resource for production today. Being renewable, delivering system services and producing the cheapest electricity possible, these are facts that recommend hydroelectricity today. Oftentimes power plants work together with storage pumping stations. Simulation and multiple-speed experimental testing work together to ensure their efficiency increase when redesigning and/or refurbishing. Very important also is the operating cost reduction. Eliminating cavitation regimes lead to a longer life for the machine. The net result is a reduced maintenance activity therefore cost cuts. Operating these stations remotely, offer the possibility to reduce the operating and maintenance costs. Data acquisition feature helps managers to better schedule the maintenance activity with the net effect of reducing the operation cost. This paper presents a testing platform retrofitted with remote control capability and camera vision to demonstrate the remote control and monitoring. Built in the lab, the experimental facility is a valuable hardware platform allowing the researcher to target different research directions.
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43

Tani, Giorgio, Michele Viviani, Diego Villa, and Marco Ferrando. "A study on the influence of hull wake on model scale cavitation and noise tests for a fast twin screw vessel with inclined shaft." Proceedings of the Institution of Mechanical Engineers, Part M: Journal of Engineering for the Maritime Environment 232, no. 3 (April 4, 2017): 307–30. http://dx.doi.org/10.1177/1475090217693418.

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The study of ship underwater radiated noise is nowadays a topic of great and largely recognized importance. This is due to the fact that in the last decades, the problem of the impact of anthropogenic noise on marine life has been addressed with higher emphasis, giving rise to different efforts aimed to the analysis of its effects on different organisms and, in parallel, to means for the reduction of shipping noise. In this context, attention is focused on the propeller noise, which, in cavitating conditions, may represent the most important noise source of the ship. The propeller noise has been studied for long time with different approaches. One of the most effective approaches is represented by model scale testing in cavitation tunnels or similar facilities. Despite having been adopted for several years, radiated noise experiments in model scale are usually affected by significant scale effects and technical issues. One of these aspects is represented by the correct modelling of the propeller inflow; different techniques are adopted, depending on the facility, in order to reproduce a certain target wake. One of the main problems is to define this target wake, which should in principle coincide with the ship wake; as it is well known, it is usually derived from model scale towing tank measurements, with the necessity for the prediction of the full-scale wake field. Starting from the outcomes of a previous work on the influence of different approaches for the prediction of the full-scale wake field for a single screw ship, in this work, attention is focused on the case of a fast twin screw vessel, analysing the different issues which may be connected to this hull form.
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44

Nikolsky, Valeriy, Roman Dychkovskyi, Edgar Cáceres Cabana, Natalia Howaniec, Bartłomiej Jura, Katarzyna Widera, and Adam Smoliński. "The Hydrodynamics of Translational−Rotational Motion of Incompressible Gas Flow within the Working Space of a Vortex Heat Generator." Energies 15, no. 4 (February 16, 2022): 1431. http://dx.doi.org/10.3390/en15041431.

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The paper presents the results of analytical and experimental studies of the hydrodynamics of the translational−rotational motion of incompressible gas flow within a working space of a variable-geometry vortex heat generator. The terminal velocity and pressure have been identified analytically. The effect of vortex generation on the ratio of the parameters has been analyzed. A mathematical model has been developed with a simplified design scheme that simulates the movement inside a vortex channel with fixed elements. On the basis of mathematical modelling, the influence of the apparatus-constructive (AC) design of the working space of a vortex heat generator on the generation of vortices inside the apparatus has been analyzed. The influence of the main geometric and hydrodynamic parameters of the device on the indicators of its energy efficiency has been investigated. The obtained models show the critical regions where the most intense cavitation zones are possible. An analysis of the hydrodynamics of the incompressible gas motion within the working space of the newly designed vortex heat generator with variable geometry has helped define both the terminal velocity and pressure. In addition, the effect of the facility geometry on the generation of vortices favoring cavitation was determined. The model studies have been carried out in terms of liquid loading changes in the 0.001–0.01 m3/s range. The changes in a velocity field within a working channel have been analyzed for the channel geometry, where a cone angle γ is 0° to 25°, with 130, 70, and 40 mm widths for the working channel. It has been identified that a sufficient axial symmetry of the heat carrier along a vortex accelerator enables the heat carrier inlet through a turbulizing nozzle. The dependence of the nozzle area, the effect on the efficiency of the vortex heat generator angle of attack of the vortex accelerator, and the ratio of the length and diameter of the vortex zone of the heat generator to its energy efficiency in general have been defined experimentally. These studies could be instrumental in the design of vortex heat generators whose geometry corresponds to the current requirements concerning energy efficiency. It has been found that the geometry of the vortex accelerator improves the operation of the heat generator by 35% in comparison with similar available designs.
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45

Dibyo, Sukmanto, Surian Pinem, and V. I. S. Wardhani. "Conceptual Design On N16 Decay Chamber For Modified TRIGA-2000 With Plate-Type Fuel." Jurnal Pengembangan Energi Nuklir 20, no. 1 (September 5, 2018): 25. http://dx.doi.org/10.17146/jpen.2018.20.1.4278.

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Conceptual Design On N16 Decay Chamber For Modified TRIGA-2000 With Plate-Type Fuel. the TRIGA-2000 is a research reactor in bandung that will be modified using plate-type fuel. The reactor core cooling system is changed from the natural convection cooling mode to the forced convection mode. The purpose of the study is to assess the conceptual design for the decay chamber of N16 nuclide in the primary cooling system of the reactor. In this design, the hold-up system decays the nuclide of N16 resulted from neutron activation product. In the period of 50 seconds, the activity of N16 (T1/2= 7.13 seconds) decays 7 time from half life to low level. The cube shape of decay chamber is provided a plate with 4 hollows and facility to flush the cavitation bubbles. The decay chamber, which is submerged into the bulk shielding as located outside of the reactor pool. The conceptual design uses the Fluent software compared with the analytical estimation for flow velocity in the decay chamber. The result shows a good agreement range with the analytical estimations. The uniform flow profile can be obtained at the velocity of about 0.4 m/s. Water flow life time of 50 seconds in the decay chamber with the capacity of 3.5 m3 is able to decay the N16 nuclide to low level. This decay chamber is expected to contribute in completing the design of reactor primary coolant system using the forced convection mode.
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46

Santucci, Joshua, Naresh Mullaguri, Anusha Battineni, Raviteja R. Guddeti, and Christopher R. Newey. "Paradoxical and Retrograde Air Embolism from Pressurized Peripheral Bolus." Case Reports in Neurological Medicine 2021 (October 5, 2021): 1–6. http://dx.doi.org/10.1155/2021/1063264.

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Introduction. Cerebral air embolism is a rare, yet serious neurological occurrence with unclear incidence and prevalence. Here, we present a case of fatal cerebral arterial and venous cerebral gas embolism in a patient with infective endocarditis and known large right-to-left shunt and severe tricuspid regurgitation following pressurized fluid bolus administration. Case Presentation. A 32-year-old female was admitted to the medical intensive care unit from a long-term acute care facility with acute on chronic respiratory failure. Her medical history was significant for intravenous heroin and cocaine abuse, methicillin-sensitive Staphylococcus aureus tricuspid valve infective endocarditis on vancomycin, patent foramen ovale, septic pulmonary embolism with cavitation, tracheostomy with chronic ventilator dependence, multifocal cerebral infarction, hepatitis C, nephrolithiasis, anxiety, and depression. After intravenous fluid administration, she became unresponsive with roving gaze, sluggish pupils, and hypotensive requiring vasopressors. CT of the brain showed diffuse arterial and venous cerebral air embolism secondary to accidental air administration from fluid bolus. Magnetic resonance imaging of the brain showed diffuse global anoxic injury and flattening of the globe at the optic nerve insertion. Given poor prognosis, her family chose comfort measures and she died. Conclusions. Fatal cerebral air embolism can occur through peripheral intravenous routes when the lines are inadequately primed and fluids administered with pressure. Caution must be exercised in patients with right-to-left shunting as air may gain access to systemic circulation.
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47

Chouhan, Priyal, Pranav Kumar Dave, Monika Puranik, Krati Khandelwal, Vivek Gupta, Rakesh Mishra, and Megha Jain. "Portable Chest X – Ray in COVID -19 Positive Cases in a Tertiary Care Centre in Central India. (A Retrospective Analysis of 739 Cases)." Asian Journal of Medical Radiological Research 8, no. 2 (December 30, 2020): 65–72. http://dx.doi.org/10.47009/ajmrr.2020.8.2.11.

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–PCR. Portable chest radiography is the first imaging modality that can be used to detect lung abnormalities and get follow up when required. Radiological findings observed in various CXR are ground-glass opacity/haziness, Consolidations, Peripheral air space opacities, diffuse air space involvement, and uncommon findings – pleural effusion, cavitation, pneumothorax, subcutaneous emphysema and pneumomediastinum. Use of Portable CXR is helpful to avoid transport of patients to CT room and subsequently avoid frequent decontamination of the CT room. Portable CXR is of much value where CT facility is not available and its use reduces radiation dose to patients and radiation staff. The objective is to analyze chest X-ray findings in proven cases of COVID -19 as per classification of British Society of Thoracic Imaging (BSTI) in the form of various radiological patterns and severity assessment. Subjects and Methods: This is a retrospective study of chest x-ray of COVID-19 positive patients, confirmed by RT-PCR and was admitted to designate COVID center: LNMC and JK Hospital, Bhopal in the duration of 31 July 2020 to 31 Aug 2020. Chest X-ray of 739 patients was studied and the mean age group was calculated. Lung involvement and pattern of distribution of disease were analyzed and classified according to BSTI classification and documented in frequencies and percentages. Results: In our retrospective analysis of a total of 739 CXR of which the number of males was 457 (61.84% ) and the number of females was 282 (38.16%). The average age group was ranging from 0 (1month) year age to 90 years age with the mean age group of 41 to 50 (20.2%). The mean age of the patients was 40.5 years. 393 (53.1%) patients have normal chest radiographs. Conclusion:The radiological findings in patients with COVID-19 infection varies with the severity of the disease. In the early phase of the disease, CXR was normal. The most common findings are basal / lower lobe consolidation more on right, followed by ground glass densities, peripheral air space densities, diffuse airspace disease. Basal / lower lobe consolidation was the usual findings in the mild category. In the moderate category, a variable pattern of all findings was seen. In the severe category of disease, diffuse air space densities and peripheral air space opacities were seen. Pleural effusion is the least seen.
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48

Gerliga, V., V. Zaporozhan, Y. Fylonych, M. Panchenko, and A. Sholudko. "EXPERIMENTAL FACILITY FOR DETERMINATION OF CAVITATIONAL PROCESSES IN THE NPP PIPELINES." Odes’kyi Politechnichnyi Universytet Pratsi 1, no. 60 (2020): 61–67. http://dx.doi.org/10.15276/opu.1.60.2020.07.

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49

Lee, Tung Lik, Jia Chuan Khong, Kamel Fezzaa, and Jia Wei Mi. "Ultrafast X-Ray Imaging and Modelling of Ultrasonic Cavitations in Liquid Metal." Materials Science Forum 765 (July 2013): 190–94. http://dx.doi.org/10.4028/www.scientific.net/msf.765.190.

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The dynamics of ultrasonic bubbles in liquid metal are captured in-situ for the first time using the ultrafast X-ray phase contrast imaging facility housed at the Advanced Photon Source, Argonne National Laboratory, in the USA. The experimental observations are complemented by the simulations of the acoustic pressure field, the bubble diameter oscillation and the associated pressure and velocity pulses at the bubble wall due to the alternating pressure wave. The experiment and simulation agree well and provide more quantitative insight into the understanding of the highly transient behaviour of the ultrasonic bubbles and their interaction with the surrounding liquid metal.
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50

Kang, Donghyuk, Kyubok Ahn, Byoungjik Lim, Sanghoon Han, Hwan-Seok Choi, Seonghyeon Seo, and Hongjip Kim. "Flow Control Characteristics of Cavitating Venturi in a Liquid Rocket Engine Test Facility." Journal of the Korean Society of Propulsion Engineers 18, no. 3 (June 1, 2014): 84–91. http://dx.doi.org/10.6108/kspe.2014.18.3.084.

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