• Title, Summary, Keyword: bubble-point

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Bubble Behavior and Radiation for Laser-Induced Collapsing Bubble in Water (물 속에서 레이저에 의하여 생성된 기포의 거동 및 복사현상)

  • Karng, Sarng-Woo;Byun, Ki-Taek;Kwak, Ho-Young
    • Proceedings of the KSME Conference
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    • pp.1282-1287
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    • 2004
  • The bubble behavior and the radiation mechanism from a laser-induced collapsing bubble were investigated theoretically using the Keller-Miksis equation for the bubble wall motion and analytical solutions for the vapor inside bubble. The calculated time dependent bubble radius is in good agreement with observed ones. The half-width of the luminescence pulse at the collapse point, which was calculated under assumption that the light emission mechanism is black body radiation from the vapor bubble agreed well with observed value of several nanoseconds. The gas content inside the vapor bubble was too small to produce the light emission due to bremsstrahlung.

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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 (열감응액정을 이용한 사각공동내의 상단냉각평판에 형성된 기포 주위의 열전달현상 구명)

  • Kwon, Gi-Han;Eom, Yong-Kyoon
    • Proceedings of the KSME Conference
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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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The Effect of a Bubble in B nard Convection at Low Rayleigh Number (낮은 Rayleigh값의 B nard Convection 유동장에 주입된 기포의 영향에 관한 연구)

  • Eom, Yong-Gyun;Gwon, Gi-Han
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.12
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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.

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

  • Lee, Kye-Bock;Kim, Young-Do
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.11
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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.

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

  • Kim, Sang-Moon;Kim, Hyun-Dong;Kim, Kyung-Chun
    • Proceedings of the KSME Conference
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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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Bubble Point Calculation using Experimental Flash Points of Binary Solutions (이성분계 용액의 인화점 실험값을 이용한 기포점 계산)

  • Ha, Dong-Myeong;Lee, Sungjin
    • Journal of the Korean Society of Safety
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    • v.31 no.6
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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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    • v.57 no.6
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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.

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

  • Choi, Hae-Man;Terauchi, T.;Monji, H.;Matsui, G.
    • The KSFM Journal of Fluid Machinery
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    • v.5 no.1
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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.

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

  • Kang, Dong-Han;Jang, Young-Ho;Kim, Jong-Su;Kim, Keug-Tae
    • Journal of Korean Society on Water Environment
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    • v.27 no.6
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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.

Prediction of Cavitation Intensity in Pumps Based on Propagation Analysis of Bubble Collapse Pressure Using Multi-Point Vibration Acceleration Method

  • Fukaya, Masashi;Ono, Shigeyoshi;Udo, Ryujiro
    • International Journal of Fluid Machinery and Systems
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    • v.2 no.2
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    • pp.165-171
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    • 2009
  • We developed a 'multi-point vibration acceleration method' for accurately predicting the cavitation intensity in pumps. Pressure wave generated by cavitation bubble collapse propagates and causes pump vibration. We measured vibration accelerations at several points on a casing, suction and discharge pipes of centrifugal and mixed-flow pumps. The measured vibration accelerations scattered because the pressure wave damped differently between the bubble collapse location and each sensor. In a conventional method, experimental constants are proposed without evaluating pressure propagation paths, then, the scattered vibration accelerations cause the inaccurate cavitation intensity. In our method, we formulated damping rate, transmittance of the pressure wave, and energy conversion from the pressure wave to the vibration along assumed pressure propagation paths. In the formulation, we theoretically defined a 'pressure propagation coefficient,' which is a correlation coefficient between the vibration acceleration and the bubble collapse pressure. With the pressure propagation coefficient, we can predict the cavitation intensity without experimental constants as proposed in a conventional method. The prediction accuracy of cavitation intensity is improved based on a statistical analysis of the multi-point vibration accelerations. The predicted cavitation intensity was verified with the plastic deformation rate of an aluminum sheet in the cavitation erosion area of the impeller blade. The cavitation intensities were proportional to the measured plastic deformation rates for three kinds of pumps. This suggests that our method is effective for estimating the cavitation intensity in pumps. We can make a cavitation intensity map by conducting this method and varying the flow rate and the net positive suction head (NPSH). The map is useful for avoiding the operating conditions having high risk of cavitation erosion.