• Title/Summary/Keyword: Mixing-Efficiency

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Modeling of Mixed Phosphors in White Light Emitting Diode (백색 발광다이오드에서의 혼합 형광체 모델링)

  • Kim, Dowoo;Gong, Dayeong;Gong, Myeongkook
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.26 no.7
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    • pp.567-574
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    • 2013
  • An optical model is proposed in the white LED using phosphor and LED chip. In this paper a new model that describes the absorption rate and quantum efficiency with increasing the mixing ratio of phosphor in silicone, and the allotment of the phosphor absorption optical power in the several phosphor mixing in the silicone. Single phosphor in silicone from the optical measurement data before and after molding, the solution to get the blue optical power and the phosphor emission optical power is proposed. By these solution the absorption rate and the quantum efficiency was obtained. The model with single phosphor mixing in the silicone the validity was confirmed.

Experimental Study on the Optimum Operation Conditions of Rapid Mixing Impellers for an Effective W.T.P. Design (정수장 효율 향상을 위한 혼화기별 최적 운전조건 산정에 관한 실험적 연구)

  • Son, Gwang-Ik
    • Journal of Korea Water Resources Association
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    • v.30 no.6
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    • pp.731-741
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    • 1997
  • Optimum design conditions of rapid mixing impellers for an effective Water Treatment Plant operation were experimentally studied by thorough examination of parameters, such as impeller type and detention time. which govern the removal efficiency of turbidity. It was found that the impeller type is one of the major parameters governing the economic power consumption and the efficiency of turbidity removal. The experimental results showed that not only the velocity gradient G but also a new design guide. so called mixing energy per unit volume of raw water, could be used as a design and operation guides for rapid mixing in W.T.P.

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Flotation Efficiency of the DAF Pump System for Mixing and Coagulation Conditions in Raw Drinking Water (상수원수의 혼화 및 응집 조건에 따른 DAF pump 장치의 부상분리효율)

  • Ahn, Kab-Hwan;Lee, Chang-Han
    • Journal of Environmental Science International
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    • v.20 no.5
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    • pp.639-645
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    • 2011
  • This study found that flotation efficiencies for removing algae and micro particles in raw water were optimized on mixing intensity and time of the mixing and flocculation conditions with a continuous DAF system. It is more efficient for mixing intensity at 23.1 $s^{-1}$ and time at 660 s(Gt value : 15246) to float flocculated floc with the raw water in M water treatment plant. Flotation efficiency was more than about 0.9 when operated pressure and A/S ratio were sustained at 5 $kg_f{\cdot}cm^{-2}$ and up to 0.056 $mL{\cdot}mg^{-1}$. The continuous DAF system made by the study could be continuously operated for 20 days and sustained not exceeding 4 NTU with raw water with low turbidity(13.4~9.8 NTU).

Shape Optimization of a Micro-Static Mixer (마이크로 믹서의 형상 최적화)

  • 한석영;김성훈
    • Proceedings of the Korean Society of Machine Tool Engineers Conference
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    • 2004.04a
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    • pp.166-171
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    • 2004
  • In this study, shape optimization of micro-static mixer with a cantilever beam was accomplished for mixing the mixing efficiency by using successive response surface approximations. Variables were chosen as the length of cantilever beam and the angle between horizontal and the cantilever beam. Sequential approximate optimization method was used to deal with both highly nonlinear and non-smooth characteristics of flow field in a micro-static mixer. Shape optimization problem of a micro-static mixer can be divided into a series of simple subproblems. Approximation to solve the subproblems was performed by response surface approximation, which does not require the sensitivity analysis. To verify the reliability of approximated objective function and the accuracy of it, ANOVA analysis and variables selection method were implemented, respectively. It was verified that successive response surface approximation worked very well and the mixing efficiency was improved very much comparing with the initial shape of a micro-static mixer.

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Studies on the Determination of Optimal Flocculation Condition in Wastewater of Recycled Paper (재생지 폐수의 최적 응집조건 결정에 관한 연구)

  • 이성호;임택준;조준형
    • Journal of Korea Technical Association of The Pulp and Paper Industry
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    • v.33 no.3
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    • pp.44-51
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    • 2001
  • Sedimentation characteristics such as SS, $BOD_5$, COD removal efficiency of waste water in the toilet paper mill using milk carton were examined. Optimum dosage of coagulant, rapid mixing time and slow mixing time were determined by turbidity, SS, COD, $BOD_5$ and then equation for treatment efficiency was suggested. Mechanical strength of floc was determined by turbidity. For the coagulant, polyacrylamide (PAM) is more efficient for removing pollution than the aluminium sulfate. Effective mixing ratios of PAM and aluminum sulfate to remove pollution are 70:30 and 30:70. The lowest turbidity was showed when rapid mixing at 300 rpm after coagulant injection was applied. That which indicates the highest point of flocs mechanical strength.

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Simulation of the Gas Exchange Process in a Two - Stroke Cycle Diesel Engine (2행정 사이클 디젤기관의 가스교환과정 시뮬레이션)

  • 고대권;최재성
    • Journal of Advanced Marine Engineering and Technology
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    • v.18 no.2
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    • pp.104-112
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    • 1994
  • The scavenging efficiency has a great influence on the performance of a diesel engine, especially slow two-stroke diesel engines which are usually used as a marine propulsion power plant. And this is greatly affected by the conditions in the cylinder, scavenging manifold and exhaust manifold during the gas exchange process. There are many factors to affect on the scavenging efficiency and these factors interact each other very complicatedly. Therefore the simulation program of the gas exchange process is very useful to improve and predict the scavenging efficiency, due to the high costs associated with redesign and testing. In this paper, a three-zone scavenging model for two-stroke uniflow engines was developed to link a control-volume-type engine simulation program for performance prediction of long-stroke marine engines. In this model it was attempted to simulate the three different regions perceived to exist inside the cylinder during scavenging, namely the air, mixing and combystion products regions, by modeling each region as a seperate control volume. Finally the scavenging efficiency was compared with three type of scavenging modes, that is, pure displacement, partial mixing and prefect mixing.

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A Computational Study of Flowfield for a Vent Mixer in Supersonic Flow (초음속 유동장 내 벤트 혼합기에 관한 수치해석 연구)

  • Kim, Chae-Hyoung;Jeung, In-Seuck
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.2
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    • pp.33-39
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    • 2008
  • To improve the mixing efficiency and to reduce the pressure loss, it is needed to develope a new mixing device for supersonic combustion. The vent mixer is introduced as the new supersonic fuel-air mixer. Computational analyses, that include pressure profile, density contour, and streamline tracing, have been carried out. The expansion wave generates at the end of the extended upper wall of the mixer. And it reduces the shock wave from the hole. Incoming air flow through the hole makes several recirculation regions which increase the mixing efficiency, and the separation region at the downward wall expends the boundary layer which reduces the pressure loss.

A Study on the Performance Improvement of Flash-Mixer in Water-Treatment Plant (정수장 급속혼화설비 성능향상에 관한 연구)

  • Cho, In-Jun;Oh, Sang Han;Lee, Sang Wook;Son, Chang Ho;Chung, Wui Jun
    • Journal of Korean Society on Water Environment
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    • v.27 no.2
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    • pp.210-217
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    • 2011
  • In results of accomplishing fundamental study to improve the flocculant-mixing of the Flash-Mixer in Onsan Water-Treatment Plant at the small cost, We obtained 8.9% of mixing-efficiency from the field data and 3.2% of the characteristic flow-ratio as the available maximum volume-ratio in this Water-Treatment Plant. The optimum elements with the deflector diameter of 400 mm and deflector angle of $145^{\circ}$ at the flow ratio of 3.2% could be obtained from the expanded study on the ground of the fundamental study. Finally, the efficiency could be improved about 510% from 8.9% to 45.4% and the average turbidity could be improved about 14%.

Effect of Fuel Mixing Ratio on Fuel Consumption in a Oil Fired Power Plant (중유화력발전소에서 바이오연료 혼합연소가 연료소비량에 미치는 영향)

  • Hong, Sangpil;Yoo, Hoseon
    • Plant Journal
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    • v.12 no.3
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    • pp.39-45
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    • 2016
  • Each of fuel consumption per hour was measured at the 320 MW and 380 MW generator output while changing mixing ratio of bio fuel oil to 50%, 80% and 100%. Fuel consumption per hour was increased from 11.0% to 20.4% as mixing ratio of bio fuel oil was changed from 50% to 100% at the 320 MW generator output comparing with fuel consumption per hour in case of bunker-C oil single firing. Fuel consumption per hour was also increased from 12.0% to 21.1% as mixing ratio of bio fuel oil was changed from 50% to 100% at the generator output 380 MW. Furthermore, it was confirmed that plant efficiency was decreased as mixing ratio of bio fuel oil was increased from 50% to 100% as a result that plant efficiency was calculated using the measured fuel consumption per hour, the generator output and the gross heating value.

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Numerical Analysis on Mixing in T type Microchannel using Throttling (스로틀링을 이용한 T형 미소 채널에서의 혼합에 관한 수치 해석적 연구)

  • Jang, Ji-Hwan;Lee, Do-Hyung
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1516-1521
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    • 2004
  • Mixing in Y-channel micro mixer is analyzed through computational fluid dynamics. In the case of passive mixing, we investigate the effect of geometric parameters on the mixing efficiency, such as shape of throttling geometry and angle between two inlets. Mixing performance improves as two fluids join not just horizontally but both vertically and horizontally, and it also improves when channel follows throttling shapes. A numerical results substantiate the highly efficient mixing performance. It is highly beneficial to fabrication process since the proposed throttling geometry is simple, but allows high mixing ratio.

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