• Title/Summary/Keyword: Rapid Mixing

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Experimental Study on Fuel-Air Mixing Using Flat Plate/Cavity in Supersonic Flow (초음속 유동장 내 평판/cavity를 이용한 연료-공기 혼합의 실험적 연구)

  • Kim, Jeong-Woo;Jeong, Eun-Ju;Kim, Chae-Hyoung;Jeung, In-Seuck
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.11a
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    • pp.319-322
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    • 2006
  • Rapid mixing of air-fuel (<1 ms) is needed to accomplish supersonic combustion. In this experiment, helium was injected laterally in to the Mach 1.92 air flow. 2 kinds of model, flat plate/cavity, were used in this experiment and images were taken by schlieren visualization. Pressure was affected by shock structure in the supersonic duct, and penetration height was increased by increasing J. Penetration height was higher in the cavity model than flat plate model.

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Simultaneous Measurement of Velocity and Concentration Field in a Stirred Mixer Using PIV/LIF Technique (PIV/LIF기법에 의한 교반혼합기 내의 속도장과 농도장 동시 측정)

  • Jeong, Eun-Ho;Yoon, Sang-Youl;Kim, Kyung-Chun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.4
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    • pp.504-510
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    • 2003
  • Simultaneous measurements of turbulent velocity and concentration field in a stirred mixer tank are carried out by using PIV/LIF technique. Instantaneous velocity fields are measured with a 1K$\times$1K CCD camera adopting the frame straddle method while the concentration fields are obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. It is found that the general features of the mixing pattern are quite dependent on the local flow characteristics during the rapid decay of mean concentration. However, the small scale mixing seems to be independent on the local turbulent velocity fluctuation.

Restraint of carbon deposition in diesel ATR using fuel atomizer (연료 미립화기를 이용한 디젤 자열개질기 내 탄소침적 억제)

  • Yoon, Sang-Ho;Kang, In-Yong;Bae, Joong-Myeon
    • 한국신재생에너지학회:학술대회논문집
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    • 2007.11a
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    • pp.67-70
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    • 2007
  • Diesel autothermal reforming has several problems such as carbon deposition in reforming reactor, sulfur poisoning of catalyst, difficulty of aromatics decomposition and mixing problems of reactants(diesel, steam, oxygen). Severe carbon deposition causes the rapid performance degradation of reformer. Carbon deposition is formed from ethylene, carbon precursor. Ethylene was generated at the homogeneous reaction zone of the reactor entrance. This phenomenon is closely linked to the mixing of reactants. In this investigation, we try to minimize the ethylene generation at the reactor entrance atomization technique.

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Evaluation on the Properties of Modified-sulfur Concrete as a Basic Study for Development of Anti-corrosive Concrete (내부식성 콘크리트 개발을 위한 기초연구로서 개질유황 혼합 콘크리트의 물성 평가)

  • Park, Sang-Soon;Na, Ok-Jung
    • Corrosion Science and Technology
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    • v.15 no.1
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    • pp.28-37
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    • 2016
  • Due to the increased construction of offshore concrete structures and the use of de-icing salts for the purpose of snow removal, the needs for the development of anti-corrosive concrete are increasing. To solve these problems, an evaluation of the mechanical and durability properties for concrete were conducted by mixing modified-sulfur as 0 %, 5 %, 10 %, 15 % cement weight ratio. Both strengths and the properties affecting durability such as water absorption coefficient, chloride ion permeability, accelerated carbonation resistance, rapid freezing and thawing, and chemical resistance were evaluated. All evaluations performed were according to the test specifications associated KS. The results indicate that mixing of modified-sulfur lowed chloride ion permeability and improved chemical resistance.

Simultaneous Measurement of Velocity and Concentration Field in a Stirred Mixer Using PIV/LIF Techniqueut and POD Analysis (PIV/LIF에 의한 교반혼합기 유동의 난류 속도/농도장 측정 및 POD해석)

  • Jeong Eun-Ho;Yoon Sang-Youl;Kim Kyung-Chun
    • 한국가시화정보학회:학술대회논문집
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    • 2002.11a
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    • pp.101-104
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    • 2002
  • Simultaneous measurement of turbulent velocity and concentration field in a stirred mixer tank is carried out by using PIV/LIF technique. Instantaneous velocity fields are measured by a $1K\times1K$ CCD camera adopting the frame straddle method while the concentration fields are obtained by measuring the fluorescence intensity of Rhodamine B tracer excited by the second pulse of Nd:Yag laser light. Image distortion due to the camera view-angle is compensated by a mapping function. It is found that the general features of the mixing pattern are quite dependent on the local flow characteristics during the rapid decay of mean concentration. However, the small scale mixing seems to be independent on the local turbulent velocity fluctuation.

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The Effects of Mixer Geometry on Hydraulic Turbulence : Computational Modeling (3-D 전산유체를 이용한 급속혼화조 형상에 따른 난류 유동장 연구)

  • Park, No-Suk;Kim, Sung-Hoon;Park, Heekyung
    • Journal of Korean Society of Environmental Engineers
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    • v.22 no.7
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    • pp.1173-1182
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    • 2000
  • The rapid mixing process has been considered as an important step in water treatment. Since the coagulant dispersion into raw water by rapid mixer can influence on the flocculation and filtration efficiency, many researchers have developed various devices and mixing methodologies. Until now, they focused attention on only coagulant dose, pH. rotating velocity and G value but overlooked the real turbulent flow and mixer geometry in rapid mixer. Therefore this paper questions the significance of turbulent flows in rapid mixer and focuses on the analysis of turbulent fluid in various mixer geometry with CFD(Computational Fluid Dynamics). The results of the jar-tests using various geometries indicate that the turbidity removal rate in a circular jar without baffle is higher than that of a circular with baffle. And the turbidity removal rate in Hudson jar is also founded to be higher than in the circular jar with baffle. The CFD simulation of velocity fields in jar demonstrates that the differences of removal rates among the various geometries are largely due to the formation of the different turbulent fluids fields with different geometries.

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Optimization of In-line Coagulation/MF Process Using On-line Streaming Potential Measurement (On-line streaming potential 측정에 의한 in-line 약품응집/정밀여과 공정의 최적화)

  • Oh, Jeong-Ik;Lee, Seockheon
    • Journal of Korean Society of Water and Wastewater
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    • v.18 no.4
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    • pp.522-528
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    • 2004
  • Microfiltration with in-line rapid coagulation for drinking water production was examined. The in-line rapid coagulation was conducted using newly developed mixing device instantaneous flash mixer. The flux decline during membrane filtration was monitored with coagulant dosage varied. Flux decline was minimized at 1.1mg/L of coagulant dosage, where streaming potential of coagulated water was near zero. The optimum dosage for the process control was explained by dimensionless distance (${\kappa}{\times}a$) of particle pairs, obtained from electrophoresis parameter describing electrostatic repulsion relative to Van der Waals energy between particle pairs in the pre-coagulated water.

Development of a Digital Down-mixer to Convert 5.1 Channel Audio Signals to Stereo Signals (5.1 채널 오디오 신호를 스테레오 신호로 변환하는 디지털 다운믹서 개발)

  • Jeon, Kwang-Sub;Cheong, Ho-Yong;Lee, Seung-Yo
    • The Transactions of The Korean Institute of Electrical Engineers
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    • v.62 no.12
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    • pp.1764-1770
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    • 2013
  • Use of the 5.1 channel audio signals suitable for the television system is improper for the radio broadcasting system, which uses the stereo audio system. Therefore, it is necessary to develop an audio down-mixer to convert 5.1 multi-channel audio signals to stereo signals for radio broadcasting. In this paper, a development of an audio down-mixer was carried out to convert 5.1 multi-channel audio signals to stereo signals. The down-mixer which was developed can use the audio signals separated from video signals, including sound signals or individual signals provided from 3-channel AES/EBU signals including Left(L), Right(R), Left Surround(Ls), Right Surround(Rs), Center(C) and Low Frequency Effect(Lfe) sounds as mixer inputs.

Physical properties of Rapid-Setting Asphalt Concrete Grouting materials (초속경형 아스팔트 콘크리트용 주입재의 물리적 특성)

  • Park Won-Chun;Mun Kyoung-Ju;Jo Young-Ho;Soh Yang-Seob
    • Proceedings of the Korea Concrete Institute Conference
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    • 2005.05b
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    • pp.377-380
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    • 2005
  • The objective of this study is to evaluate the physical properties of rapid-setting asphalt concrete grouting materials. This study investigates the fluidity, viscosity and compressive strength at 3-hour of grouting materials with various mixing ratio. From the test results, when the quantity of CSA is over about 30 $\%$, the compressive strength of 3-hour was satisfied a minimum requirement of 7 days in Japan. Also, the fluidity for the time to infiltrate into pore of the asphalt concrete are enough to be applied in construction field.

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A Stud on the Water Vapor Permeability of Air Cell Structure of Ultra Rapid Harding Membrane Waterproofing Using Fixed Screw Hybrid Method (고정형 스크류 혼합 방식을 이용한 초속경 도막방수층 에어 셀 구조의 수증기투과성에 관한 연구)

  • Kim, Yun-Ho;Kim, Hyun-Min;Park, Jin-Sang;Song, Je-Young;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2013.05a
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    • pp.225-226
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    • 2013
  • Existing polyurethane membrane waterproofing has been raised defects such as heaving. Therefore, We will be utilizing as the basic experimental data by the water vapor permeability test to the air cell structure of ultra rapid harding membrane waterproofing using the static mixing system in this study.

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