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  • Title/Summary/Keyword: Droplet Model

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Numerical Analysis for Breakup of Liquid Jet in Crossflow (기체 유동에 수직 분사된 액체의 분해에 대한 수치적 해석)

  • Park, Sun-Il;Chang, Keun-Shik;Moon, Yun-Wan;Sah, Jong-Youb
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1629-1633
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    • 2004
  • Liquid is commonly introduced as transversal jets in venturi scrubber which is one of the gas cleaning equipments. The jet dynamics such as penetration and breakup is of fundamental importance to the dust-collection efficiency. We have developed a model that can numerically simulate the breakup of the liquid jet in crossflow. This simulation consists of models on liquid column, jet surface breakup, column fracture and secondary droplet breakup. These models have been embedded in the KIVA3-V code. We have calculated such parameters as the jet penetration, jet trajectory, droplet size, velocity field and the volume flux distribution. The results are compared with the experimental data in this paper.

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The Evaluation of Heat Flux by Evaporating Droplet on the Hot Surface (고온 표면에 부착된 증발 액적에 의한 열유속 변화 추정)

  • Shin, Woon-Chul;Bae, Sin-Chul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.9
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    • pp.764-771
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    • 2007
  • The objective of the present work is to evaluate the evaporation heat flux of deposited droplet on the hot surface by using of inverse heat transfer technique. On the basis of measured temperature, a integral form solution is determined for the transient temperatures beyond the two positions by using Green's function technique. This method first approximates the temperature data with a half polynomial series of time. we compared this result with constant radius model in single phase regime, nucleate boiling regime, film boiling regime respectively. this paper performed the experiments as following conditions: (a)the surface temperature is within the range between 80Cand160C in the conduction, (b) droplet diameter are 2.4 and 3.0mm. (c) surface roughness is 0.18μm.

The Effects of Solvents in Reservior Solution on Protein Crystallization Using Vapor Diffusion method (증기확산법에 의한 단백질 결정화에 미치는 Reservicr 용액의 영향)

  • 이정희;정용제
    • Korean Journal of Crystallography
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    • v.5 no.1
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    • pp.33-38
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    • 1994
  • 'Heterogeneous' vapor diffusion experiments were carried out using hen egg white Iysozyme and equine serum albumin as model proteins: droplets were equilibrated against reservoir solutiorls containing an alternative precipitant which is different from results showed that the use of polyethylene glycol as an alternative precipitant instead of NaCl or ammonium sulfate reduces equilibration rate between droplet and reservoir solution. By using the heterogeneous vapor diffusion techniqlue it is possible to control the equilibration rate by adjusting the relative amounts of ionic salts and nonionic yecipitants in reservoir solutions.

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Numerical Analysis of the Effect of Injection Pressure Variation on Impaction Spray Characteristics (분사압력변화가 충돌분무특성에 미치는 영향에 관한 수치적 고찰)

  • 김승철
    • Journal of Advanced Marine Engineering and Technology
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    • v.23 no.1
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    • pp.47-53
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    • 1999
  • Small compression-ignition direct injection engines have been developed as a measure to improve a fuel efficiency and reduce harmful exhaust gases. Those small engines generally employ high injection pressure increase on the spray impacting on a wall is discussed in this paper. The gas phase is modelled by the Eulerian continuum conservation equations of mass momentum energy and fuel vapour fraction. The liquid phases is modelled following the discrete droplet model approach in Lagrangian form and the droplet wall interaction is modelled as a func-tion of the velocity normal to impaction lands. The droplet distributions vapor fractions and gas flows are analyzed in various injection pres-sure cases. The penetrations of wall spray and vapor increase and the Sauter mean diameter decreases with increasing injection pressure.

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The Effect of Impinging Land Size on Diesel Spray Behavior in OSKA Type Combustion Chamber (OSKA형 연소실에서 충돌면크기변화가 디젤분무거동에 미치는 영향)

  • 임덕경;박권하
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.4
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    • pp.18-26
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    • 2001
  • OSKA engine was developed to remove the dense core of injection sprays. The engine uses impinging spray on a small pip, which spray after impinging is broken into smaller drops and disperses into fee space in chamber. In this paper the pip size is analyzed to give more dispersion of spray and fuel vapor. The gas phase is modelled by the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction. The liquid phase is modelled following the discrete droplet model approach in Lagrangian form, and the droplet wall interaction is modelled as a function of the velocity normal to impaction lands. The droplet distributions, vapor fractions and gas flows are analyzed for various injection pressure cases. Numerical results indicate that the land diameter of 5.6mm has the best performance of spray dynamics and vaporization in the test sizes.

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Development of droplet entrainment and deposition models for horizontal flow

  • Schimpf, Joshua Kim;Kim, Kyung Doo;Heo, Jaeseok;Kim, Byoung Jae
    • Nuclear Engineering and Technology
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    • v.50 no.3
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    • pp.379-388
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    • 2018
  • Models for the rate of atomization and deposition of droplets for stratified and annular flow in horizontal pipes are presented. The entrained fraction is the result of a balance between the rate of atomization of the liquid layer that is in contact with air and the rate of deposition of droplets. The rate of deposition is strongly affected by gravity in horizontal pipes. The gravitational settling of droplets is influenced by droplet size: heavier droplets deposit more rapidly. Model calculation and simulation results are compared with experimental data from various diameter pipes. Validation for the suggested models was performed by comparing the Safety and Performance Analysis Code for Nuclear Power Plants calculation results with the droplet experimental data obtained in various diameter horizontal pipes.

Reverse tracking method for concentration distribution of solutes around 2D droplet of solutal Marangoni flow with artificial neural network (인공신경망을 통한 2D 용질성 마랑고니 유동 액적의 용질 농도 분포 역추적 기법)

  • Kim, Junkyu;Ryu, Junil;Kim, Hyoungsoo
    • Journal of the Korean Society of Visualization
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    • v.19 no.2
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    • pp.32-40
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    • 2021
  • Vapor-driven solutal Marangoni flow is governed by the concentration distribution of solutes on a liquid-gas interface. Typically, the flow structure is investigated by particle image velocimetry (PIV). However, to develop a theoretical model or to explain the working mechanism, the concentration distribution of solutes at the interface should be known. However, it is difficult to achieve the concentration profile theoretically and experimentally. In this paper, to find the concentration distribution of solutes around 2D droplet, the reverse tracking method with an artificial neural network based on PIV data was performed. Using the method, the concentration distribution of solutes around a 2D droplet was estimated for actual flow data from PIV experiment.

Effects of Aerosolized Sanitizers of Different Droplet Sizes on Foodborne Pathogen Reduction

  • Kim, Young-Ho;Jo, Young-Jun;Kim, Yun-Ji;Koo, Min-Seon;Lee, Jong-Kyung;Oh, Se-Wook
    • Food Science and Biotechnology
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    • v.17 no.3
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    • pp.664-668
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    • 2008
  • The diffusivity of aerosol sanitizers may be determined by the weight and droplet size of the aerosol. To test the effects of droplet size, 2 types of aerosol sanitizers were prepared using different ultrasonic nebulizer frequencies (1.6 and 2.4 MHz) and their reduction activities were determined against Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella typhimurium. A sodium hypochlorite aerosol was treated for 10, 30, or 60 min in a model aerosol cabinet. When the aerosol prepared by nebulizing at 1.6 MHz was treated for 30 min, a 0.2 log reduction was observed in E. coli O157:H7 and 0.3 log reductions were exhibited in L. monocytogenes and S. typhimurium, respectively. After 60 min, the 3 pathogens were reduced by 1.7, 0.6, and 0.8 log units, respectively. However, when the aerosol prepared by nubulizing at 2.4 MHz was treated, the microbes presented 1.6, 0.5, and 0.6 log reductions at 30 min, and 1.8, 0.9, and 1.1 log reductions at 60 min of treatment, respectively.

Thermal Wave Transfer and Combustion Response of Droplet Perturbed by Acoustic Pressure (압력파에 교란된 액적내부에서의 에너지 파동 및 반응 메커니즘)

  • Lee Cilyong;Yoon Woongsub
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • v.y2005m4
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    • pp.183-188
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    • 2005
  • This study targets to investigate thermal wave transfer in a droplet strongly coupled with acoustic pressure and its effects on combustion response. The one-dimensional vaporization model uses SRK equation of state and flash calculation method to obtain more accurate thermophysical properties and compute vapor-liquid equilibrium. Calculations of an n-pentane droplet exposed into a perturbing nitrogen gas is carried out in terms of different ambient gas pressures and wave frequencies. The thermal wave is transferred more effectively at lower frequencies, which results in the decrease in the amplitude of the response.

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