• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.510-516
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• 1988

The effects of input substrate concentration and dilution rate on mass transfer resistance in the operation of immobilized cell reactors were investigated using Rhodospirillum rubrum KS-301 immobilized by Ca alginate as reactor element and glucose as growth-limiting substrate. The kinetic parameters were obtained to estimate effectiveness factors. In the packed-bed reactor, internal mass transfer resistance was predominating although external resistance could not be neglected. The overall effectiveness factor was decreased with increase of dilution rate. In the continuous stirred-tank reactor, external resistance was nearly neglected and the overall effectiveness factor was not affected by dilution rate. In this experiment the overall effectiveness factors in PBR and CSTR were estimated to be 0.70 and 0.71 at D$_{i}$ = 0.2/h, R = 0.15 cm, and S$_{i}$ : 1.0g/L, respectively.

• Transactions of the Korean Society of Automotive Engineers
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• v.6 no.3
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• pp.63-70
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• 1998

According to the stringent exhaust emission regulation control of air fuel ratio is one of the most important issues on gasoline engine. Although many researches have been carried out to identify the fuel transport phenomena in a port fueled gasoline engine, complexity of fuel film behavior in the intake port makes it difficult. The fuel film behavior was investigated recently by using visualization method and these gave us qualitative understanding. In this paper, the quantitative measurement method for the port fuel film is studied by using Fast Response Flame Ionization Detector(FRFID). The mass of fuel film on the port wall was measured by using the methods of fuel injection off, injection on and regression. The Fuel film mass was increased with incresing load at the same engine speed.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.84-85
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• 1994

본 연구는 수용상에 포함된 중금속이온중 에멀젼 액막법(Emulsion Liquid Membranes, ELM)을 이용하여 납이온을 제거시키기 위한 연구이다. 지금까지 수용액상의 중금속 이온의 제거는 전통적으로 이온 침전법을 사용하여 왔다. 그러나 이 방법은 스럿지 처리문제가 남아 있고 식수로 이용되는 수처리에는 식수기준 만족도 때문데 적합하지 않았다. ELM법에 의한 금속이온 제거처리는 전기도금에 의하여 중금속이온을 회수할 수 있고 고도의 수처리를 가능케하여 최근 많은 관심을 갖고 있다. 본 연구에서는 납 이온 추출제로서 D2EPHA와 Alamine336의 이온교환제를 사용하여, 이 씨스테므이 추출 평형자료를 구하고 pH, 추출제의 농도, 교반속도, 에멀젼비율등에 의한 추출효과등을 검토하였다. 또한 2단계 추출 방법을 사용하여 금속이온추출에서 가장 큰 문제점인 유기상 용액의 leakage를 해결하고자 하였다.

• Applied Chemistry for Engineering
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• v.8 no.5
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• pp.763-770
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• 1997

The separation of benzene-cyclohexane mixture using (O/W)/O emulsion liquid membrane was studied. The operating parameters which can affect the selectivity, benzene yield, and emulsion size distribution were examined and determined by the batch type operation. The unsteady state and steady state extraction behavior in continuous pulse stirred reactor(CPSR) were verified. The optimum conditions for benzene selectivity and yield in batch operation were as follows; emulsion mixing intensity 4000 rpm, Tween 80 concentration 0.4%, volume ratio of membrane phase to internal phase 0.75, volume ratio of dispersed phase to continuous phase 0.5, and permeation time 10 minutes, As impeller speed increased and the microdrop holdup decreased, the Sauter mean diameter decreased. Turbulence damping parameter of modified Calabrease correlation considering microdrop holdup was 2.28. The optimum conditions of continuous operation were as follows; agitation speed 300 rpm, pulse frequence 2 times/sec, flow rate of continuous phase 30ml/min, and flow rate of emulsion phase 12.0ml/min.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.253-256
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• 2009

In the micro turbojet engine less than 350kw power class, it is not easy to find out the good atomization fuel injector with good spray quality. However conceptually, rotating fuel injection system can give high atomization quality by only the centrifugal force of a high speed rotating shaft of the engine without high-pressure fuel pump. With this motivation, we manufactured very small rotating fuel injector of 40 mm diameter and performed under a variety of injection orifices. We measured droplet size, velocity and spray distribution by the PDPA(Phase Doppler Particle Analyzer) system. Also spray was visualized by using high speed camera. From the test results, we could understand that the length of liquid column from the injection orifice is mainly controlled by the rotational speeds. Furthermore, droplet size(SMD) is decreased with the rotational speeds and is influenced by the diameter of the injection orifice and liquid film thickness.

• Applied Chemistry for Engineering
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• v.9 no.7
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• pp.943-949
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• 1998

This study is concerned with the treatment of landfill leachate by carrier meditated emulsion. Using the batch operation, the optimum conditions for the removal of anionic and cationic materials were obtained. The landfill leachate from the plant was experimented under these conditions. The experimental variables were surfactant (Arlacel80) concentration and carrier(Aiquat336, DEHPA) concentration in membrane phase and counter ion concentration in internal phase. More than 80%(COD) of landfill leachate component could be removed within 12 minutes. The most crucial experimental variable for the removal efficiency was carrier concentration in membrane phase. In the other variables, the reaction time was more effected than the removal efficiency.

• Korean Chemical Engineering Research
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• v.56 no.5
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• pp.687-693
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• 2018

The selective removal and recovery of fermentation inhibitors during purification of sugars from biomass hydrolysates can increase the economic efficiency of the entire process to produce bioalcohol from lignocellulosic biomass. This study investigated the effect of furans in phenols-free biomass hydrolysate on acetic acid extraction in an emulsion liquid membrane system. Under specific operating conditions, more than 99% of acetic acid could be extracted within 5 minutes, and the degrees of extraction of furfural and 5-hydroxymethylfurfural were about 10% and 4%, respectively. The extraction rate of acetic acid was also lower at a higher initial concentration of furfural in the feed phase, which was greater for furfural than 5-hydroxymethylfurfural. Thus, if furfural is first removed from the hydrolysate prior to acetic acid extraction, emulsion liquid membrane would be a more economically efficient way of removing acetic acid.

• Journal of the Korean Society of Propulsion Engineers
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• v.11 no.5
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• pp.37-50
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• 2007

This study investigated the characteristics of spray generated by a liquid coaxial swirl injector used in a combustor of the liquid rocket engine. The linear stability analysis considered long and short wave was introduced in liquid sheet breakup. Through the hydrodynamic analysis the initial liquid sheet thickness spray angle and injection velocity were predicted. To evaluate the effect of turbulence model standard $k-{\varepsilon}$ and RNC $k-{\varepsilon}$ model were applied to numerical calculation and it was known that RNC $k-{\varepsilon}$ model was more applicable to predict spray characteristics. On the basis of this evaluation validation of the developed model was performed with swirl injector installed in LPRE and the predicted results of breakup length, spray angle, and SMD agreed well with experiments qualitatively and quantitatively.

• Membrane Journal
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• v.14 no.4
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• pp.275-288
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• 2004

Carbon dioxide was absorbed into water-in-oil (w/o) emulsion composed of aqueous 2-amino-2-methyl-1-propanol (AMP) droplets as a dispersed phase and benzene solutions of polybutene and polyisobutylene as a continuous phase in a flat-stirred vessel to investigate the effect of non-Newtonian rheological behavior on the rate of chemical absorption of $CO_2$, where the reaction between $CO_2$ and AMP in the aqueous phase was assumed to be a pseudo-first-order reaction. It was expressed that PIB with elastic property made the rate of chemical absorption of $CO_2$ accelerated by comparison of mass transfer coefficient of $CO_2$ in the non-Newtonian liquid with that in the Newtonian liquid.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.7
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• pp.567-578
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• 2015

Single droplet-wall collision heat transfer characteristics on a heated plate above Leidenfrost temperature were experimentally investigated considering the effects of impact velocity. The collision characteristics of the droplet impinged on the heated wall and the changes in temperature distribution were simultaneously measured using synchronized high-speed video and infrared cameras. The surface heat flux distribution was obtained by solving the three-dimensional transient heat conduction equation for the heated substrate using the measured surface temperature data as the boundary condition for the collision surface. As the normal impact velocity increased, heat transfer effectiveness increased because of an increase in the maximum spreading diameter and a decrease in the vapor film thickness between the droplet and heated wall. For We < 30, droplets stably rebounded from a heated wall without breakup. However, the droplets broke up into small droplets for We > 30. The tendency of the heat transfer to increase with increasing impact velocity was degraded by the transition from the rebounding region to the breakup region; this was resulted from the reduction in the effective heat transfer area enlargement due to the breakup phenomenon.