• Title/Summary/Keyword: gas-liquid mixing

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A Study on the Ralstonia Solanacearum Inactivation using Improved Plasma Process (개선된 플라즈마 공정을 이용한 Ralstonia Solanacearum 불활성화에 관한 연구)

  • Kim, Dong-Seog;Park, Young-Seek
    • Journal of Environmental Science International
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    • v.23 no.3
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    • pp.369-378
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    • 2014
  • Effect of improvement of the dielectric barrier discharge (DBD) plasma system on the inactivation performance of bacteria were investigated. The improvement of plasma reactor was performed by combination with the basic plasma reactor and UV process or combination with the basic plasma reactor and circulation system which was equipped with gas-liquid mixer. Experimental results showed that tailing effect was appeared after the exponential decrease in basic plasma reactor. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of basic plasma process and UV process. The application of gas-liquid mixing device on the basic plasma reactor reduced inactivation time and led to complete sterilization. The effect existence of gas-liquid mixing device, voltage, air flow rate (1 ~ 5 L/min), water circulation rate (2.8 ~ 9.4 L/min) in gas-liquid mixing plasma, plasma voltage and UV power of gas-liquid mixing plasma+UV process were evaluated. The optimum air flow rate, water circulation rate, voltage of gas-liquid mixing system were 3 L/min, 3.5 L/min and 60 V, respectively. There was no enhancement effect on the Ralstonia Solanacearum inactivation with combination of gas-liquid mixing plasma and UV process.

Prediction of Flow Rate and Drop Size of Low Viscosity Liquid Through Y-Jet Atomizers (Y-Jet노즐을 통한 저점도 액체의 유량 및 입경예측에 관한 연구)

  • 송시홍;이상용
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.12
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    • pp.3377-3385
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    • 1994
  • This paper introduces empirical correlations to obtain the gas/liquid flow rates and the spray drop size of low viscosity liquid injected by Y-jet twin-fluid atomizers. The gas flow rate is well correlated with the gas injection pressure and the mixing point pressure, based on the compressible flow theory. Similarly, the liquid flow rate is determined by the liquid injection pressure and the mixing point pressure, and a simple correlation for the liquid discharge coefficient at the liquid port was deduced from the experimental results. The mixing point pressure, which is one of the essential parameters, was expressed in terms of the gas/liquid flow rate ratio and the mixing port length. Disintegration and atomization mechanisms both within the mixing port and outside the atomizer were carefully re-examined, and a "basic" correlation form representing the mean diameter of drops was proposed. The "basic" correlation was expressed in terms of the mean gas density within the mixing port, gas/liquid mass flow rate ratio and the Weber number. Though the correlation is somewhat complicated, it represents the experimental data within an accuracy of ${\pm}15%$.EX>${\pm}15%$.

An experimental study on the mixing of evaporating liquid spray in a duct flow (덕트 유동에서 증발을 수반하는 액상 스프레이의 혼합 특성에 대한 실험적 연구)

  • Kim, Y.B.;Choi, S.M.
    • Journal of ILASS-Korea
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    • v.11 no.1
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    • pp.30-38
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    • 2006
  • High temperature furnaces such as power plant and incinerator contribute considerable part of NOx generation and face urgent demand of De-NOx system. Reducing agent is injected into the flue gas flow to activate do-NOx system. Almost SCR system adopt vaporized ammonia injection system. Vaporizer, dilution system and additional space are needed to gasify and inject ammonia. Liquid spray injection system can simplify and economize post-treatment system of flue gas. In this study, mixing caused by gas or liquid injection of reducing agent into flue gas duct was investigated experimentally. Carbonated water was used as tracer and simulated agent and mixing of liquid spray in a duct flow was studied. To achieve that, the angle of attack of static mixer is simulated and $CO_2$ concentration is measured.

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Micro-Gravity Research on the Atomization Mechanism of Near-Critical Mixing Surface Jet

  • Tsukiji, Hiroyuki;Umemura, Akira;Hisida, Manabu
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2004.03a
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    • pp.774-778
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    • 2004
  • The atomization process of a circular $SF_{6}$ liquid jet issued into an otherwise quiescent, high-pressure $N_2$ gas was observed to explore the breakup mechanism of liquid ligaments involved in turbulent atomization. Both liquid and gas temperatures were fixed at a room temperature but the gas pressure was elevated to more than twice the critical pressure of $SF_{6}$. Therefore, the liquid surface was in a thermodynamic state close to a critical mixing condition with suppressed vaporization. Since the surface tension and the surface gas density approach zero and the surface liquid density, respectively, phenomena equivalent to those which would appear when a very high speed laminar flow of water were injected into the atmospheric-pressure air can be observed by issuing $SF_{6}$ liquid at low speeds in micro-gravity environment which avoid disturbances due to gravity forces. The instability ob near-critical mixing surface jet was quantitatively characterized using a newly developed device, which could issue a very small amount of $SF_{6}$ liquid at small constant velocity into a very high-pressure $N_2$ gas.

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Study on the Gas-Liquid Mixing Characteristics in Reactor System Using Ejector

  • Jin, Zhen-Hua;Utomo, Tony;Chung, Han-Shik;Jeong, Hyo-Min;Shin, You-Sik;Lee, Sang-Chul
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2708-2713
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    • 2007
  • The aim of this paper is further studies to achieve deeper understanding in this field. First investigate the influence of operating conditions and design parameters on the hydrodynamics and the mass transfer properties of a loop reactor. This paper provides a literature review on the ejectors applications in the mixing system. A number of studies are grouped and discussed in several topics such as the background, theory of ejector, mixing characteristics, optimization of the system. Since the high efficiencies reactor using ejector widely used in gas-liquid system, especially in a number of chemical and biochemical processes. This is due to their high efficiency in gas dispersion resulting in high mass transfer rate and low power requirements. Thus ejector has been applied to the mixing system. An investigation on hydrodynamics and mass transfer characteristics of gas-liquid ejector has been carried out using three-dimensional CFD modeling.

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Relationship between void fraction and mixing in bubble column flow (기포탑 유동에서의 기포분율과 혼합정도의 상관관계)

  • Zahidul, Islam MD;Lee, Jubeom;Park, Hyungmin
    • Journal of the Korean Society of Visualization
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    • v.15 no.1
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    • pp.41-46
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    • 2017
  • Control of mixing and transport processes are the key areas that can be benefited by understanding the hydrodynamics in gas-liquid two-phase flows. In particular, the enhanced bubble-induced liquid-phase mixing is known to be a function of void fraction distribution, gas phase velocity and so on. To further our insight on the characteristics of the liquid-phase mixing induced by the bubbles, in the present study, we experimentally investigate the mixing performance of a rectangular bubble column while changing the void fraction from 0.006 to 0.075%. A shadowgraphy technique is used to measure the gas-phase properties such as void fraction and size/velocity of bubbles. On the other hand, we use dye visualization with low diffusive buoyant dye to directly measure the level of mixing. Finally, we confirm that the time taken for full mixing scales with the inverse of volume void fraction.

Mixing Effect by the Geometry of Static Mixer with Turbulent In-Situ Mixing Process (난류 용탕 In-Situ 합성법을 위한 스태틱 믹서의 형상에 따른 혼합 효과)

  • Lee, Dae-Sung;Kim, Hyo-Geun;Ha, Man-Yeong;Park, Yong-Ho;Park, Ik-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.12 s.243
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    • pp.1307-1312
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    • 2005
  • Turbulent in-situ mixing process is a new material process technology to get dispersed phase in nanometer size by controlling reaction of liquid/liquid, liquid/solid and liquid/gas, flow and solidification speed simultaneously. In this study mixing, the key technology to this synthesis method will be studied by computational fluid dynamics. For the simulation of mixing of liquid metal, static mixers will be investigated. Two inlets for different liquid metal meet and merge like 'Y' shape tube. The tube has various shapes such as straight and curved. Also, the radius of curve will be varied. The performance of mixer will be evaluated with quantitative analysis with coefficient of variance of mass fraction. Also, detailed plots of intersection will be presented to understand effect of mixer shape on mixing.

A Study on Cooling Characteristics of Combustion Gas by Liquid Nitrogen in a Liquid Rocket Engine (액체질소를 이용한 액체 로켓 엔진 연소 가스 냉각 특성 연구)

  • Jeon, Jun-Su;Lee, Yang-Suk;Song, Jae-Kang;Kim, Yoo;Ko, Young-Sung
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.147-150
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    • 2007
  • In this study, cooling characteristics of combustion gas were investigated by injecting liquid nitrogen into liquid rocket combustion chamber. A injection ring of liquid nitrogen was installed between a combustion chamber and a mixing chamber which was designed for mixing of combustion gas and nitrogen. At first, a ignition test of liquid rocket engine was conducted to verify a stable combustion process and 10 second combustion tests were successfully conducted. The results showed that combustion gas of LRE could be cooled by using liquid nitrogen.

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Spray Characteristics on Shape of Twin Fluid atomizer by Internal Mixing Chamber Type (내부혼합형 2유체 분사노즐의 형상에 따른 분무특성)

  • 윤수환;정대인;하종률
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.4
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    • pp.43-52
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    • 1994
  • I investigated experomentally the spray characteristics to the operating conditions and the shapes of internal mixing twin fluid atomizer. The wide variations of air per liquid ratio are conducted to predit the influences of the Sauter mean diameter(SMD), spray angle, distribution of drop size, the flowing condition of gas and length, flowing, area of gas and liquid, and diameter, number and place of the orifice. In this experiment, air per liquid raio, mixing chamber length per diameter, orifice diameter, and the flowing area ratio of gas and fluid influences greatly on SMD, spray angle, distribution of drop size and intermittent fluctuation region.

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Effects of Ethanol Mixing Ratio on Spray Characteristics of Triplet Impinging Injector (에탄올 혼합비에 따른 3중 충돌형 인젝터의 분무특성)

  • Lee, In-Chul;Kim, Jong-Hyun;Koo, Ja-Ye
    • Journal of the Korean Society for Aviation and Aeronautics
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    • v.15 no.4
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    • pp.1-8
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    • 2007
  • Spray characteristics of a unlike triplet injector were investigated experimentally. Spray images and SMD of droplet were measured to evaluate the spray characteristics injected by liquid/gas combinations. G-L-G(Gas-Liquid-Gas), L-G-L(Liquid-Gas-Liquid) type of injector were used by changing the gas and liquid feed lines. The SMD graph shows that the droplet sizes decrease in the out of radial direction at a fixed gas Reynolds number. The SMD value of decreasing tendency shows that the more ethyl alcohol ratio increase, the more SMD value decrease.

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