DOCSLIB.ORG

Effects of Bubble on the Viscosity Properties of Lubricant

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Effects of Bubble on the Viscosity Properties of Lubricant Proceedings of WTC2005 World Tribology Congress III September 12-16, 2005,Proceedings Washington, of WTC2005 D.C., USA World Tribology Congress III September 12-16, 2005, Washington, D.C., USA WTC2005-64114WTC2005-64114 EFFECTS OF BUBBLE ON THE VISCOSITY PROPERTIES OF LUBRICANT Ng, W. S. Levesley, M. C. Priest, M. School of Mechanical Engineering School of Mechanical Engineering School of Mechanical Engineering The University of Leeds The University of Leeds The University of Leeds Leeds, LS2 9JT, UK Leeds, LS2 9JT, UK Leeds, LS2 9JT, UK ABSTRACT Einstein [1] reported the increase of viscosity with gas volume Air ingestion and entrapment is prevalent in the lubricant fraction in a dilute suspension of solid particles: circulating around internal combustion engine and can lead to η = (1+ 2.5φ)η (1) formation of two-phase flow system referred to as bubbly oil l which affecting the oil viscosity and overall damping Taylor [2] derived a theoretical viscosity model which shared capability. Experimental work is conducted to study the the same conclusion with Einstein. effective viscosity of bubbly oil in a simple shear rheometer η = (1+ φ)ηl (2) with the aim of gaining a general understanding of the two- For Hayward [3], he experimentally derived the viscosity phase mixture flow and developing lubrication models to be model of bubbly oil as used in subsequent analysis. A laboratory simulator is used to (3) produce bubbly oil by controlling the system pressure, η = (1+ 0.15φ)ηl temperature, and gas content entrained from atmosphere and an All researchers shared the same conclusion that the bubbly oil enclosed rheometer is employed to measure the mixture viscosity increases with gas volume fraction or bubble content viscosity. A new detailed design is incorporated into the percentage (vol%). The only difference among those models is commercial rheometer with the purpose of maintaining the the coefficient of the gas volume fraction. distribution of bubbles within the lubricant. The transparent test chamber is initially pressurized with air to control the bubbly The aim of this research is to study the effective viscosity oil level and the bubbly oil viscosity is tested over a wide range of bubbly oil with the knowledge of bubble content using a of shear rates. Under shearing motion, the viscosity of bubbly commercial aerator and sealed cone-and-plate rheometer. oil varies with time and the results obtained are compared to Bubbly oil viscosity is predicted to be shear and time that of single-phase oil. dependence since bubbles are deformable under the rheometer shearing motion. Keywords: bubbly oil, viscosity, shear rate, gas volume fraction NOMENCLATURE INTRODUCTION η Bubbly oil effective viscosity, Pa.s Air entrainment phenomenon in journal bearings or ηl Lubricant viscosity, Pa.s squeeze film dampers has been reported for years and its effect φ Gas volume fraction on load carrying capacity is of significant concern. The effect is attributed to the formation of gas bubbles in lubricant. Bubbly METHOD oil is defined as two-phase flow where the mixture consists of The experimental setup consists of two main parts, an continuous liquid phase and discrete bubbles. The flow aerator and a rheometer. The aeration apparatus is behaviour of bubbly oil attracts the attention of variety of fields manufactured by IFT (Ingenieurgesellschraft fur of researchers because of its complexity exhibited. This is Triebwerkstechnik) mbH, Germany, and is designed for mainly due to the existence of bubbles has modified the supplying aerated oil. Oil is drawn from a heated bath by an properties, especially the viscosity as the main concern in electrically driven oil pump. The oil supply unit is equipped engine lubrication, of a single-phase unaerated lubricant. Much with an oil aeration unit to adjust the content of air in the oil at work in investigating bubbly oil viscosity has been done but the low pressure inlet to the pump. The pump discharges into a most of the models developed are not applicable in journal high pressure circuit (about 20 to 30 bars) to ensure complete bearing performance analysis. air dissolution into the oil and then through a pressure regulator 1 Copyright © 2005 by ASME to a lower pressure circuit to release air as bubbles in a controlled manner and achieve the pressure or flow necessary to feed the rheometer. In the progress of delivering bubbly oil 70.00 5 vol% into the rheometer, the gas volume fraction is measured by 10 vol% comparing the volume difference of (un)aerated oil collected in 60.00 15 vol% a cylinder. 20 vol% As shown in Fig. 1, in the rheometer, a metal platform base 50.00 Viscosity, mPa.s (4) is duplicated and the aerated oil is delivered in (Qin) and out 40.00 (Qout) from bottom tappings located in the lower base plate. The bubbly liquid is delivered into the test station under the rotating bore, which is cone-and-plate. In addition, a metal enclosure 30.00 plate (3) is used to close the test station and to house two 20.00 tappings; one for a pressure regulator and the other for a tube. Effective Average The pressure regulator and tube are needed to pressurize the 0 50 100 150 200 250 300 inner space of the enclosure to control the bubbly oil level and Shear Rate, 1/s to suck out the excessive bubbly oil respectively. A transparent Figure 2. Average effective viscosity for 5, 10, 15, and 50 vol% perspex enclosure wall (5) is installed to allow observation of aeration at 30°C under the shear rate range from 50 to 250s-1. potential phenomena such as bubble coalescence and large- scale flow patterns. To further improve the sealing effect, a low The first stage of experiment was carried out to obtain the motion resistance Teflon/Delrin ring (2) has been employed. single phase unaerated lubricant viscosity at 30°C as a reference for bubbly oil. Viscometry measurement showed that 5, 10, 15, and 20 vol% aeration has increased the unaerated lubricant viscosity. Generally, the bubbly oil showed a shear- thinning characteristic where its viscosity decreases with shear rate. At low shear rate of 50s-1, the bubbles have significantly increased the lubricant viscosity; at high shear rate of 100s-1 onwards, the bubbly oil viscosity remains almost constant but is higher than the unaerated lubricant viscosity. In addition, the bubbly oil viscosity also increased with vol% at low shear rate of 50s-1 due to the bubbles shape remaining unchanged and increasing the resistance of flow. At higher shear rates of 100s-1 onwards, however, the applied shear rate has brought the bubbles into interaction and breakup. Figure 1. Sealed rheometer This has been observed that the lubricant volume reduced when the measurement was completed. However the viscosity of Effective viscosities as a function of rotation rate are bubbly oil is still higher than that of unaerated oil. This could determined by comparing the torque required to shear the gap- be explained where small bubbles were observed at the centre filling bubbly oil to the torque required to shear pure lubricant of cone-and-plate when the cone-and-plate is lifted for next at the same shear rate and temperature. Single shear rate at measurement. particular temperature is applied for approximately 200s to investigate the time-dependent viscosity; average effective CONCLUSIONS viscosity at different shear rates is obtained by averaging the A simple experiment has been conducted to evaluate the time-dependent viscosity to view the shear rate effect on bubbly effect of gas content on the viscosity of lubricant. In general, oil viscosity. the existence of bubbles has elevated the single phase lubricant. However, the original structure of bubbles contained in Table 1. Test Parameters lubricant has been destructed due to the small gap setting Parameter Data (150µm) under cone-and-plate rheometer and the high applied Lubricant HVI 60 (single grade shear rate. From the data collected and observation, the bubbles hydraulic oil) appear to coalesce to form large bubbles under the cone-and- Lubricant viscosity 37.1 mPa.s at 30°C plate at the beginning of the viscosity measurement and Lubricant aeration at 1.013 bar 5, 10, 15, and 20 vol% breakup or expel under high operating shear rates. Cone-and-plate gas setting 150 µm Operating shear rate 50-250 s-1 REFERENCES [1] Einstein, A., 1906, “Eine neue Bestimmung der RESULTS Molekuldimensionen,” Annln Phys., 19, 289-306. 2 Copyright © 2005 by ASME .
Load more

Recommended publications
  • Observation of Elliptically Polarized Light from Total Internal Reflection in Bubbles
    Observation of elliptically polarized light from total internal reflection in bubbles Item Type Article Authors Miller, Sawyer; Ding, Yitian; Jiang, Linan; Tu, Xingzhou; Pau, Stanley Citation Miller, S., Ding, Y., Jiang, L. et al. Observation of elliptically polarized light from total internal reflection in bubbles. Sci Rep 10, 8725 (2020). https://doi.org/10.1038/s41598-020-65410-5 DOI 10.1038/s41598-020-65410-5 Publisher NATURE PUBLISHING GROUP Journal SCIENTIFIC REPORTS Rights Copyright © The Author(s) 2020. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License. Download date 29/09/2021 02:08:57 Item License https://creativecommons.org/licenses/by/4.0/ Version Final published version Link to Item http://hdl.handle.net/10150/641865 www.nature.com/scientificreports OPEN Observation of elliptically polarized light from total internal refection in bubbles Sawyer Miller1,2 ✉ , Yitian Ding1,2, Linan Jiang1, Xingzhou Tu1 & Stanley Pau1 ✉ Bubbles are ubiquitous in the natural environment, where diferent substances and phases of the same substance forms globules due to diferences in pressure and surface tension. Total internal refection occurs at the interface of a bubble, where light travels from the higher refractive index material outside a bubble to the lower index material inside a bubble at appropriate angles of incidence, which can lead to a phase shift in the refected light. Linearly polarized skylight can be converted to elliptically polarized light with efciency up to 53% by single scattering from the water-air interface. Total internal refection from air bubble in water is one of the few sources of elliptical polarization in the natural world.
    [Show full text]
  • A Monte Carlo Ray Tracing Study of Polarized Light Propagation in Liquid Foams
    ARTICLE IN PRESS Journal of Quantitative Spectroscopy & Radiative Transfer 104 (2007) 277–287 www.elsevier.com/locate/jqsrt A Monte Carlo ray tracing study of polarized light propagation in liquid foams J.N. Swamya,Ã, Czarena Crofchecka, M. Pinar Mengu¨c- b,ÃÃ aDepartment of Biosystems and Agricultural Engineering, 128 C E Barnhart Building, University of Kentucky, Lexington, KY 40546, USA bDepartment of Mechanical Engineering, 269 Ralph G. Anderson Building, University of Kentucky, Lexington, KY 40506, USA Received 10 July 2006; accepted 28 July 2006 Abstract A Monte Carlo ray tracing scheme is used to investigate the propagation of an incident collimated beam of polarized light in liquid foams. Cellular structures like foam are expected to change the polarization characteristics due to multiple scattering events, where such changes can be used to monitor foam dynamics. A statistical model utilizing some of the recent developments in foam physics is coupled with a vector Monte Carlo scheme to compute the depolarization ratios via Stokes–Mueller formalism. For the simulations, the incident Stokes vector corresponding to horizontal linear polarization and right circular polarization are considered. It is observed that bubble size and the polydispersity parameter have a significant effect on the depolarization ratios. This is partially owing to the number of total internal reflection events in the Plateau borders. The results are discussed in terms of applicability of polarized light as a diagnostic tool for monitoring foams. r 2006 Elsevier Ltd. All rights reserved. Keywords: Polarized light scattering; Liquid foams; Bubble size; Polydispersity; Foam characterization; Foam diagnostics; Cellular structures 1. Introduction Liquid foams are random packing of bubbles in a small amount of immiscible liquid [1] and can be found in a wide variety of applications.
    [Show full text]
  • The Synergistic Effect of Focused Ultrasound and Biophotonics to Overcome the Barrier of Light Transmittance in Biological Tissue
    Photodiagnosis and Photodynamic Therapy 33 (2021) 102173 Contents lists available at ScienceDirect Photodiagnosis and Photodynamic Therapy journal homepage: www.elsevier.com/locate/pdpdt The synergistic effect of focused ultrasound and biophotonics to overcome the barrier of light transmittance in biological tissue Jaehyuk Kim a,b, Jaewoo Shin c, Chanho Kong c, Sung-Ho Lee a, Won Seok Chang c, Seung Hee Han a,d,* a Molecular Imaging, Princess Margaret Cancer Centre, Toronto, ON, Canada b Health and Medical Equipment, Samsung Electronics Co. Ltd., Suwon, Republic of Korea c Department of Neurosurgery, Brain Research Institute, Yonsei University College of Medicine, Seoul, Republic of Korea d Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada ARTICLE INFO ABSTRACT Keywords: Optical technology is a tool to diagnose and treat human diseases. Shallow penetration depth caused by the high Light transmission enhancement optical scattering nature of biological tissues is a significantobstacle to utilizing light in the biomedical field. In Focused Ultrasound this paper, light transmission enhancement in the rat brain induced by focused ultrasound (FUS) was observed Air bubble and the cause of observed enhancement was analyzed. Both air bubbles and mechanical deformation generated Mechanical deformation by FUS were cited as the cause. The Monte Carlo simulation was performed to investigate effects on transmission Rat brain by air bubbles and finiteelement method was also used to describe mechanical deformation induced by motions of acoustic particles. As a result, it was found that the mechanical deformation was more suitable to describe the transmission change according to the FUS pulse observed in the experiment. 1.
    [Show full text]
  • Ocean Storage
    277 6 Ocean storage Coordinating Lead Authors Ken Caldeira (United States), Makoto Akai (Japan) Lead Authors Peter Brewer (United States), Baixin Chen (China), Peter Haugan (Norway), Toru Iwama (Japan), Paul Johnston (United Kingdom), Haroon Kheshgi (United States), Qingquan Li (China), Takashi Ohsumi (Japan), Hans Pörtner (Germany), Chris Sabine (United States), Yoshihisa Shirayama (Japan), Jolyon Thomson (United Kingdom) Contributing Authors Jim Barry (United States), Lara Hansen (United States) Review Editors Brad De Young (Canada), Fortunat Joos (Switzerland) 278 IPCC Special Report on Carbon dioxide Capture and Storage Contents EXECUTIVE SUMMARY 279 6.7 Environmental impacts, risks, and risk management 298 6.1 Introduction and background 279 6.7.1 Introduction to biological impacts and risk 298 6.1.1 Intentional storage of CO2 in the ocean 279 6.7.2 Physiological effects of CO2 301 6.1.2 Relevant background in physical and chemical 6.7.3 From physiological mechanisms to ecosystems 305 oceanography 281 6.7.4 Biological consequences for water column release scenarios 306 6.2 Approaches to release CO2 into the ocean 282 6.7.5 Biological consequences associated with CO2 6.2.1 Approaches to releasing CO2 that has been captured, lakes 307 compressed, and transported into the ocean 282 6.7.6 Contaminants in CO2 streams 307 6.2.2 CO2 storage by dissolution of carbonate minerals 290 6.7.7 Risk management 307 6.2.3 Other ocean storage approaches 291 6.7.8 Social aspects; public and stakeholder perception 307 6.3 Capacity and fractions retained
    [Show full text]
  • Bubble-Mania the Bubbling Clues to Magma Viscosity and Eruptions
    Earthlearningidea - http://www.earthlearningidea.com/ Bubble-mania The bubbling clues to magma viscosity and eruptions Pour a viscous liquid (eg. honey, syrup) into Honey and a one transparent container and a pale-coloured soft drink – ready for soft drink (eg. ginger beer) or just coloured bubble-mania. water into another. Put both of these onto a plastic tray or table. Ask your pupils to use a drinking straw to blow bubbles into the soft Apparatus photo: drink, then ask them to ‘use the same blow’ to Chris King blow bubbles in the more viscous liquid. When nothing happens, ask them to blow harder until the liquid ‘erupts’. Ask: • How were the ‘eruptions’ different? • How were the bubbles different? • What caused the differences? • Some volcanoes have magmas that are Magma fountain ‘runny’ (like the soft drink) and some have within the crater much more viscous magmas (like the other of Volcan liquid) – how might these volcanoes erupt Villarrica, Pucón, differently? Chile. • Which sort of eruption would you most like to This file is see – one with low viscosity (runny) magma, licensed by Jonathan Lewis like the soft drink, or one with high viscosity under the Creative (thick) magma like the viscous liquid? Commons Attribution-Share Alike 2.0 Generic license. ……………………………………………………………………………………………………………………………… The back up Title: Bubble-mania • How were the ‘eruptions’ different? It was easy to blow bubbles into the soft drink Subtitle: The bubbling clues to magma viscosity and it ‘fizzed’ a bit, but the bubbles soon and eruptions disappeared; it was much harder to blow bubbles into the viscous liquid and they grew Topic: A simple test of the viscosity of two similar- large and sometimes burst out of the container looking liquids, linked to volcanic eruption style.
    [Show full text]
  • The Life of a Surface Bubble
    molecules Review The Life of a Surface Bubble Jonas Miguet 1,†, Florence Rouyer 2,† and Emmanuelle Rio 3,*,† 1 TIPS C.P.165/67, Université Libre de Bruxelles, Av. F. Roosevelt 50, 1050 Brussels, Belgium; [email protected] 2 Laboratoire Navier, Université Gustave Eiffel, Ecole des Ponts, CNRS, 77454 Marne-la-Vallée, France; fl[email protected] 3 Laboratoire de Physique des Solides, CNRS, Université Paris-Saclay, 91405 Orsay, France * Correspondence: [email protected]; Tel.: +33-1691-569-60 † These authors contributed equally to this work. Abstract: Surface bubbles are present in many industrial processes and in nature, as well as in carbon- ated beverages. They have motivated many theoretical, numerical and experimental works. This paper presents the current knowledge on the physics of surface bubbles lifetime and shows the diversity of mechanisms at play that depend on the properties of the bath, the interfaces and the ambient air. In particular, we explore the role of drainage and evaporation on film thinning. We highlight the existence of two different scenarios depending on whether the cap film ruptures at large or small thickness compared to the thickness at which van der Waals interaction come in to play. Keywords: bubble; film; drainage; evaporation; lifetime 1. Introduction Bubbles have attracted much attention in the past for several reasons. First, their ephemeral Citation: Miguet, J.; Rouyer, F.; nature commonly awakes children’s interest and amusement. Their visual appeal has raised Rio, E. The Life of a Surface Bubble. interest in painting [1], in graphism [2] or in living art.
    [Show full text]
  • Study on Bubble Cavitation in Liquids for Bubbles Arranged in a Columnar Bubble Group
    applied sciences Article Study on Bubble Cavitation in Liquids for Bubbles Arranged in a Columnar Bubble Group Peng-li Zhang 1,2 and Shu-yu Lin 1,* 1 Institute of Applied Acoustics, Shaanxi Normal University, Xi’an 710062, China; [email protected] 2 College of Science, Xi’an University of Science and Technology, Xi’an 710054, China * Correspondence: [email protected]; Tel.: +86-181-9273-7031 Received: 24 October 2019; Accepted: 29 November 2019; Published: 4 December 2019 Featured Application: This work will provide a reference for further simulations and help to promote the theoretical study of ultrasonic cavitation bubbles. Abstract: In liquids, bubbles usually exist in the form of bubble groups. Due to their interaction with other bubbles, the resonance frequency of bubbles decreases. In this paper, the resonance frequency of bubbles in a columnar bubble group is obtained by linear simplification of the bubbles’ dynamic equation. The correction coefficient between the resonance frequency of the bubbles in the columnar bubble group and the Minnaert frequency of a single bubble is given. The results show that the resonance frequency of bubbles in the bubble group is affected by many parameters such as the initial radius of bubbles, the number of bubbles in the bubble group, and the distance between bubbles. The initial radius of the bubbles and the distance between bubbles are found to have more significant influence on the resonance frequency of the bubbles. When the distance between bubbles increases to 20 times the bubbles’ initial radius, the coupling effect between bubbles can be ignored, and after that the bubbles’ resonance frequency in the bubble group tends to the resonance frequency of a single bubble’s resonance frequency.
    [Show full text]
  • Bubble Size and Bubble Concentration of a Microbubble Pump with Respect to Operating Conditions
    energies Article Bubble Size and Bubble Concentration of a Microbubble Pump with Respect to Operating Conditions Seok-Yun Jeon 1,2, Joon-Yong Yoon 1 and Choon-Man Jang 2,* 1 Department of Mechanical Engineering, Hanyang University, 55 Hanyangdeahak-ro, Sangnok-gu, Ansan, Gyeonggi-do 15588, Korea; [email protected] (S.-Y.J.); [email protected] (J.-Y.Y.) 2 Department of Land, Water and Environment Research, Korea Institute of Civil Engineering and Building Technology, 283, Goyangdae-ro, Ilsanseo-gu, Goyang-si, Gyeonggi-do 10223, Korea * Correspondence: [email protected]; Tel.: +82-31-910-0494 Received: 8 June 2018; Accepted: 12 July 2018; Published: 17 July 2018 Abstract: The present paper describes some aspects of the bubble size and concentration of a microbubble pump with respect to flow and pressure conditions. The microbubble pump used in the present study has an open channel impeller of a regenerative pump, which generates micro-sized bubbles with the rotation of the impeller. The bubble characteristics are analyzed by measuring the bubble size and concentration using the experimental apparatus consisting of open-loop facilities; a regenerative pump, a particle counter, electronic flow meters, pressure sensors, flow control valves, a torque meter, and reservoir tanks. To control the intake, and the air flowrate upstream of the pump, a high precision flow control valve is introduced. The bubble characteristics have been analyzed by controlling the intake air flowrate and the pressure difference of the pump while the rotational frequency of the pump impeller was kept constant. All measurement data was stored on the computer through the NI (National Instrument) interface system.
    [Show full text]
  • The Dual Effect of Viscosity on Bubble Column Hydrodynamics
    Chemical Engineering Science 158 (2017) 509–538 Contents lists available at ScienceDirect Chemical Engineering Science journal homepage: www.elsevier.com/locate/ces The dual effect of viscosity on bubble column hydrodynamics ⁎ crossmark Giorgio Besagnia, , Fabio Inzolia, Giorgia De Guidob, Laura Annamaria Pellegrinib a Politecnico di Milano, Department of Energy, Via Lambruschini 4a, 20156 Milano, Italy b Politecnico di Milano, Dipartimento di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Piazza Leonardo da Vinci 32, 20133 Milano, Italy ARTICLE INFO ABSTRACT Keywords: Some authors, in the last decades, have observed the dual effect of viscosity on gas holdup and flow regime Bubble column transition in small-diameter and small-scale bubble columns. This work concerns the experimental investiga- Flow regime transition tion of the dual effect of viscosity on gas holdup and flow regime transition as well as bubble size distributions in Bubble size distributions and shapes a large-diameter and large-scale bubble column. The bubble column is 5.3 m in height, has an inner diameter of Gas holdup 0.24 m, and can be operated with gas superficial velocities in the range of 0.004–0.20 m/s. Air was used as the Viscosity dispersed phase, and various water-monoethylene glycol solutions were employed as the liquid phase. The Aspect ratio correlation water-monoethylene glycol solutions that were tested correspond to a viscosity between 0.9 mPa s and 7.97 mPa s, a density between 997.086 kg/m3 and 1094.801 kg/m3, a surface tension between 0.0715 N/m and 0.0502 N/m, and log10(Mo) between −10.77 and −6.55 (where Mo is the Morton number).
    [Show full text]
  • On the Shape of Giant Soap Bubbles
    On the shape of giant soap bubbles Caroline Cohena,1, Baptiste Darbois Texiera,1, Etienne Reyssatb,2, Jacco H. Snoeijerc,d,e, David Quer´ e´ b, and Christophe Claneta aLaboratoire d’Hydrodynamique de l’X, UMR 7646 CNRS, Ecole´ Polytechnique, 91128 Palaiseau Cedex, France; bLaboratoire de Physique et Mecanique´ des Milieux Het´ erog´ enes` (PMMH), UMR 7636 du CNRS, ESPCI Paris/Paris Sciences et Lettres (PSL) Research University/Sorbonne Universites/Universit´ e´ Paris Diderot, 75005 Paris, France; cPhysics of Fluids Group, University of Twente, 7500 AE Enschede, The Netherlands; dMESA+ Institute for Nanotechnology, University of Twente, 7500 AE Enschede, The Netherlands; and eDepartment of Applied Physics, Eindhoven University of Technology, 5600 MB, Eindhoven, The Netherlands Edited by David A. Weitz, Harvard University, Cambridge, MA, and approved January 19, 2017 (received for review October 14, 2016) We study the effect of gravity on giant soap bubbles and show The experimental setup dedicated to the study of such large 2 that it becomes dominant above the critical size ` = a =e0, where bubbles is presented in Experimental Setup, before information p e0 is the mean thickness of the soap film and a = γb/ρg is the on Experimental Results and Model. The discussion on the asymp- capillary length (γb stands for vapor–liquid surface tension, and ρ totic shape and the analogy with inflated structures is presented stands for the liquid density). We first show experimentally that in Analogy with Inflatable Structures. large soap bubbles do not retain a spherical shape but flatten when increasing their size. A theoretical model is then developed Experimental Setup to account for this effect, predicting the shape based on mechan- The soap solution is prepared by mixing two volumes of Dreft© ical equilibrium.
    [Show full text]
  • Calculation of the Mass Transfer Coefficient for the Dissolution of Multiple Carbon Dioxide Bubbles in Sea Water Under Varying C
    Journal of Marine Science and Engineering Article Calculation of the Mass Transfer Coefficient for the Dissolution of Multiple Carbon Dioxide Bubbles in Sea Water under Varying Conditions Hee-Joo Cho and Jungho Choi * Department of Naval Architecture and Offshore Engineering, Dong-A University, 49315 Busan, Korea; [email protected] * Correspondence: [email protected] Received: 2 November 2019; Accepted: 11 December 2019; Published: 13 December 2019 Abstract: Underwater weapon systems with reforming fuel cells have been developed to increase the number of possible days that the former can be submerged. Reforming hydrocarbons generate a large quantity of carbon dioxide gas that must be completely dissolved in water and released. In this study, the mass transfer coefficient was derived experimentally while changing the process variables that affect mass transfer, such as bubble size, presence/absence of an inline mixer, retention time, pressure, and solvent type. It was found that retention time was most affected, followed by type of solvent, presence/absence of the inline mixer, and bubble size. In addition, by reducing bubble size and retention time and applying an inline mixer, the effect can be like that dissolved at high pressure even at low pressure. Applications of this study are expected to reduce the size of underwater weapon systems. Therefore, further studies on increasing the power consumption of underwater weapon systems due to reduction of bubble size and the application of inline mixers should be conducted. Keywords: air independent propulsion system; underwater weapon system; hydrocarbon reforming; carbon dioxide; mass transfer; mass transfer coefficient; multiple bubble; dissolution 1. Introduction Underwater weapon systems equipped with air independent propulsion (AIP) have been constructed recently to increase their submerged operation period [1].
    [Show full text]
  • Inside a Collapsing Bubble: Sonoluminescence and the Conditions During Cavitation
    ANRV340-PC59-26 ARI 1 December 2007 17:10 V I E E W R S I E N C N A D V A Inside a Collapsing Bubble: Sonoluminescence and the Conditions During Cavitation Kenneth S. Suslick1 and David J. Flannigan2 1School of Chemical Sciences, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801; email: [email protected] 2California Institute of Technology, Pasadena, California 91125; email: fl[email protected] Annu. Rev. Phys. Chem. 2008. 59:659–83 Key Words The Annual Review of Physical Chemistry is online at sonochemistry, hydrodynamics, ultrasound, plasma, optical http://physchem.annualreviews.org emission spectroscopy This article’s doi: 10.1146/annurev.physchem.59.032607.093739 Abstract Copyright c 2008 by Annual Reviews. Acoustic cavitation, the growth and rapid collapse of bubbles in a All rights reserved liquid irradiated with ultrasound, is a unique source of energy for 0066-426X/08/0505-0659$20.00 driving chemical reactions with sound, a process known as sono- chemistry. Another consequence of acoustic cavitation is the emis- sion of light [sonoluminescence (SL)]. Spectroscopic analyses of SL from single bubbles as well as a cloud of bubbles have revealed line and band emission, as well as an underlying continuum arising from a plasma. Application of spectrometric methods of pyrometry as well as tools of plasma diagnostics to relative line intensities, profiles, and peak positions have allowed the determination of intracavity temper- atures and pressures. These studies have shown that extraordinary conditions (temperatures up to 20,000 K; pressures of several thou- sand bar; and heating and cooling rates of >1012 Ks−1) are generated within an otherwise cold liquid.
    [Show full text]