• 제목/요약/키워드: bubble-point

검색결과 118건 처리시간 0.031초

기-액 기둥에서 기포유동에 관한 연구 (A Study on the Bubble Flow in the Gas-Liquid Plume)

  • 서동표;홍명석;오율권
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 춘계학술대회
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    • pp.2105-2108
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    • 2003
  • The characteristics of upward bubble flow were experimentally investigated in a liquid bath. In the present study, a thermal-infrared camera and high speed CCO camera were used to measure their temperature and local rising velocity, respectively. Heat transfer from bubble surface to water is largely completed within z=10mm from the nozzle, and then the temperature of bubble surface reaches that of water rapidly. The rising velocity of bubble was calculated for two different experimental conditions: 1) bubble flow without kinetic energy 2) with kinetic energy. Bubble flow without kinetic energy starts to undergo the effect of inertia force 10cm away from the nozzle. Whereas, kinetic energy is dominant before 30 cm away from the nozzle in bubble flow, but after this point, kinetic energy and inertial force are applied on bubble flow at the same time.

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열감응액정을 이용한 사각공동내의 상단냉각평판에 형성된 기포 주위의 열전달현상 구명 (Experimental study of heat transfer in the surrounding for bubble attached at the upper cooled surface of square cavity using the Thermo-sensitive Liquid-crystal Tracer)

  • 권기한;엄용균
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2001년도 춘계학술대회논문집D
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    • pp.509-515
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    • 2001
  • In a square cavity, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the. visualized image. As the growing of a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to thermocapillary convection.

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낮은 Rayleigh값의 B nard Convection 유동장에 주입된 기포의 영향에 관한 연구 (The Effect of a Bubble in B nard Convection at Low Rayleigh Number)

  • 엄용균;권기한
    • 대한기계학회논문집B
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    • 제25권12호
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    • pp.1879-1886
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    • 2001
  • n a enclosed square cavity occurred B nard convection, the flow phenomena in the surrounding of the bubble attached at the upper cooled solid wall were studied by using a thermo-sensitive liquid-crystal tracer and image processing techniques. This method offers the advantage of measuring the entire flow field in a selected plane within the fluid at a given instant of time in contrast to point by point method like T/C. Quantitative data of the temperature were obtained by applying a colour-image-processing to the visualized image. As the flowing in a bubble, In a bubble size appears the flow phenomena which the direction of flow is reversed in the entire temperature and flow field. The observed phenomena are described with regard to the thermocapillary convection.

다상모델을 이용한 탁도계 버블트랩 내부 유동장에 관한 고찰 (A Study on the Flow Fields of Bubble Trap of Turbidimeter Using the Multiphase Model)

  • 이계복;김영도
    • 대한기계학회논문집B
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    • 제31권11호
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    • pp.963-970
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    • 2007
  • The objectives of this study are to examine a bubble trap mechanism of the turbidimeter for low turbidity and to acquire it's technology concerned. Reynolds-Averaged Wavier-Stokes equation and Laglangian discrete phase model were applied to analyze a flow field in the bubble trap. 3D hybrid grid system was used to simulate the flow field of bubble trap and numbers of it's node point are about 110,000. From the comparison between the standard $k-{\varepsilon}$ model and the laminar state, it was found that the former estimated less the velocity in the outlet of bubble trap than the latter did, and that the former estimated more the shear stress at the wall of bubble trap than the latter did. And, it was possible to visualize the path of bubbles in the bubble trap and to copy the removal process of bubbles out bubble trap. Also, it was found that nearly most of bubbles in the bubble trap disappeared.

PIV 기법과 Digital Mask 기법을 적용한 버블유동 측정 (The Measurement of Bubble Driven Flow Using PIV and Digital Mask Technique)

  • 김상문;김현동;김경천
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2700-2703
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    • 2008
  • An experiment on bubble-driven flow was performed in order to understand fundamental knowledge of flow structure around a rising bubble in a stagnant fluid. The measurement technique consists of a combination of the three most often used PIV techniques in multiphase flows: PIV with fluorescent tracer particles, the digital phase separation with a masking technique and a shadowgraphy. The key point of the measurement is that the background intensity of a PIV recording can be shifted to a higher level than a bubble region using a shadowgraphy in order to distinguish from fluorescent particles and a bubble as well. Flow fields were measured without an inaccurate analysis around a fluid-bubble interface by using only one camera simply.

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이성분계 용액의 인화점 실험값을 이용한 기포점 계산 (Bubble Point Calculation using Experimental Flash Points of Binary Solutions)

  • 하동명;이성진
    • 한국안전학회지
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    • 제31권6호
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    • pp.39-44
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    • 2016
  • Suitable design and operation of distillation process is very dependent on vapor-liquid equilibrium calculation. The usual calculation method is use binary interaction parameter. Flash points of n-propanol+n-butanol and 2-butanol+n-butanol were measured by Seta-flash closed cup tester. Experimental Flash points were compared with those calculated by the method based on Raoult's law and the optimization method using Wilson equation. The binary interaction parameters obtained by the optimization method are then used to calculate the bubble points of n-propanol+n-butanol and 2-butanol+n-butanol.

Bubble-Point Measurement of Binary Mixture for the CO2 + Caprolactone Acrylate System in High Pressure

  • Jeong, Jong-Dae;Byun, Hun-Soo
    • Korean Chemical Engineering Research
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    • 제57권6호
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    • pp.826-831
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    • 2019
  • Experimental data of phase equilibrium is reported for caprolactone acrylate in supercritical carbon dioxide. Bubble-point data was measured by synthetic method at temperatures ranging from (313.2 to 393.2) K and pressures up to 55.93 MPa. In this research, the solubility of carbon dioxide for the (carbon dioxide + caprolactone acrylate) system decreases as temperature increases at a constant pressure. The (carbon dioxide + caprolactone acrylate) system exhibits type-I phase behavior. The experimental result for the (carbon dioxide + caprolactone acrylate) system was correlated with Peng-Robinson equation of state using mixing rule. The critical property of caprolactone acrylate was predicted with the Joback and Lyderson method.

Hybride PIV에 의한 단일입자/기포운동에 관한 연구 (Flow Characteristics in a Particle/Bubble Motion with Hybride PIV)

  • 최해만;사내강;문자수명;송정강일
    • 한국유체기계학회 논문집
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    • 제5권1호
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    • pp.7-12
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    • 2002
  • As the first step to investigate the fundamental mechanism of a dispersed two-phase flow, we studied the detailed interactions between bubble or particle motion and flow around it. Experiments were carried out with a rising bubble or particle in stagnant water in a vertical pipe. Particles with different densities, and/or different shapes were used for comparison with a bubble. We adopted 3D-PTV (Three-Dimensional Particle Tracking Velocimetry) for measuring the bubble or particle motions, and PIV (Particle Image Velocimetry) for measuring the water flow simultaneously (Hybrid PIV). The experimental results showed that the oblate spheroidal solid particle rose along the longer axis direction at the point that the inclination of the longer axis reached the maximum, and the inclination direction changed after moving. The bubble moved to the direction that the spheroid's projected width grew up to the largest, and the minor axis of the oblate spheroidal body of the bubble was parallel to the moving direction. The trajectory of the center of the particle/bubble which was measured with 3D-PTV, was marked on the section (x-y) of the pipe. It exhibited the pattern of the particle/bubble motion.

New Bubble Size Distribution Model for Cryogenic High-speed Cavitating Flow

  • Ito, Yutaka;Tomitaka, Kazuhiro;Nagasaki, Takao
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2008년 영문 학술대회
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    • pp.700-710
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    • 2008
  • A Bubble size distribution model has been developed for the numerical simulation of cryogenic high-speed cavitating flow of the turbo-pumps in the liquid fuel rocket engine. The new model is based on the previous one proposed by the authors, in which the bubble number density was solved as a function of bubble size at each grid point of the calculation domain by means of Eulerian framework with respect to the bubble size coordinate. In the previous model, the growth/decay of bubbles due to pressure difference between bubble and liquid was solved exactly based on Rayleigh-Plesset equation. However, the unsteady heat transfer between liquid and bubble, which controls the evaporation/condensation rate, was approximated by a theoretical solution of unsteady heat conduction under a constant temperature difference. In the present study, the unsteady temperature field in the liquid around a bubble is also solved exactly in order to establish an accurate and efficient numerical simulation code for cavitating flows. The growth/decay of a single bubble and growth of bubbles with nucleation were successfully simulated by the proposed model.

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미세기포 오존과 생물여과 시스템을 이용한 생활하수의 3차 처리에 관한 연구 (Tertiary Treatment of Sewage by Micro Bubble Ozone and BAF System)

  • 강동한;장영호;김종수;김극태
    • 한국물환경학회지
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    • 제27권6호
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    • pp.877-884
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    • 2011
  • In this paper, the removal characteristics of dissolved organic carbon (DOCs) by micro bubble ozonation process and $O_3/UV$ process were comparatively studied. In the point of DOC removing reaction coefficient, micro bubble ozonation system and $O_3/UV$ process had not significant difference, $0.0120sec^{-1}$ and $0.0141sec^{-1}$. Therefore micro bubble ozonation process is more suitable for tertiary treatment of sewage in the point of installation and maintenance cost-reducing. The optimum ozone injection rate was 2.0 g $O_3/g$ DOC and HRT was 3 min for the micro bubble ozonation process. The removal efficiency of DOC and SUVA in micro bubble ozonation system was 32.8% and 58.3% respective. Biological aerated filter (BAF) process was installed to remove soluble organic material increased by micro bubble ozonation system. And the effluent BOD of BAF was below 1.0 mg/L. In the view of cost-effectiveness, $O_3/BAF$ process was more profitable than $O_3/UV/BAF$ process for tertiary treatment of sewage. In order to nitrify ammonia in the BAF process completely, $NH_4{^+}-N$ concentration in the influent water of BAF should be designed considering low water temperature in the winter season.