• 제목/요약/키워드: mixing blade

검색결과 56건 처리시간 0.019초

임펠러 형상에 따른 교반기의 유동특성에 관한 연구 (A Study on the Flow Characteristics of Mixer by Impeller Types)

  • 양창조;최민선;이영호
    • Journal of Advanced Marine Engineering and Technology
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    • 제27권7호
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    • pp.899-905
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    • 2003
  • Mixers are used in several industrial applications where it is necessary to strongly mix reactants in a short period of time (eg. reaction injection molding, ceramics manufacturing, crystallization). However, despite their widespread use, mixing flow characteristics in these systems have not been rigorously investigated. Influence of blade shapes on the mixing time and the power consumption per unit volume in two kinds of impeller including the mixing effects are studied by PIV experiment. A series of the experiments were carried out to achieve a better mixing effect in simple baffle arrangement and tall vessel with modified impellers(two kinds of blades : pitched blade turbine and rushton turbine). Results show that periodic vortex from the mixing layer is predominant and related unsteady flow characteristics prevail over the entire region.

특수교반날개를 사용한 DCM 공법의 지반 관입 특성에 대한 사례연구 (Case Studies of Penetration Characteristics of DCM Wall Using Spiral Mixing Blades in Soil Layers)

  • 정두회;정경환;양태선
    • 한국지반공학회논문집
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    • 제23권3호
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    • pp.133-140
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    • 2007
  • DCM공법(심층혼합처리 공법)은 흙막이 벽체 등 구조물 조성에 적용하였다. 이러한 DCM 벽체는 경질층에서 관입능력이 있어야 한다. DCM 장비에 부착된 교반날개에 의해 경질지반의 관입능력이 증가되는 알아보기 위해 특수교반날개가 고안되었다. 경질점토층에 관입되는 특수교반날개의 관입특성은 김해와 인천현장에서 조사하였다. 고안한 특수교반날개는 관입속도가 다소 느려도 N=30 이상 되는 지반까지 관입되었고 관입시 효율이 경질지반에서 낮아질 수 있으므로 경제적인 교반날개의 관입깊이를 분석하였다.

정상 간섭 익렬 계산 모델을 용한 1단 축류 송풍기의 성능 예측 (Performance Prediction of the 1-Stags Axial Fan using Steady Coupled Blade Row Calculation Model)

  • 손상범;주원구;조강래
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 1998년도 유체기계 연구개발 발표회 논문집
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    • pp.49-54
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    • 1998
  • The flow inside an axial turbomachinery with multi-stage can be characterized as unsteady phenomena. In order to predict accurately these complex unsteady flow patterns including rotor-stator interaction effects, enormous computer resources are required. So it is not compatible in preliminary design process. In this study, steady coupled blade row flow with rotor-stator interaction solver is developed using interrow mixing model and used to predict the performance of the axial fan. To verify the computational method, the calculations are compared with experimental results and show satisfactory agreement with them. The interaction effects on the performance of the axial fan have also been studied by comparing the results of steady coupled blade row and steady single blade row flow calculation.

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부분흡입노즐방식의 터빈시스템에 대한 성능 평가 (Performance Evaluations for the Partial-Admission Type Turbine System)

  • 홍창욱;박승경;남궁혁준;김경호;김영수;우유철
    • 한국추진공학회:학술대회논문집
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    • 한국추진공학회 2001년도 제17회 학술발표회 논문초록집
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    • pp.11-14
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    • 2001
  • 3-D compressible flow analysis was conducted by using mixing plane method for turbine system which is consisted of partial admission nozzle and rotor. Computational results are shown oblique shock wave in blade leading and trailing edge and also shown flow separation along suction surface of blade due to abrupt blade curvature. But computational results are well agree with 1-D calculation results and experimental data.

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혼합기 블레이드 설계변수에 따른 입자의 혼합성능 연구 (Effects of Design Parameters of Mixer Blades on Particle Mixing Performance)

  • 황선필;박상현;손동우
    • 한국전산구조공학회논문집
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    • 제30권4호
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    • pp.363-370
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    • 2017
  • 본 논문에서는 원통형 혼합기를 대상으로 블레이드의 각도, 길이, 개수 및 블레이드와 탱크 바닥과의 간극을 설계변수로 선정하고, 각각의 설계변수가 혼합성능에 미치는 영향을 분석하였다. 이산요소법을 이용하여 임펠러 회전에 의한 고체 입자의 혼합공정을 해석하였으며, 혼합지수를 도입하여 혼합성능을 정량적으로 평가하였다. 다양한 설계변수의 조합을 고려한 실험계획법으로 설계변수의 주효과와 교호작용을 분석함으로써, 블레이드 각도가 입자의 혼합성능에 가장 지배적인 영향을 미치며 간극의 영향은 상대적으로 작다는 결론을 도출할 수 있었다. 또한 가장 우수한 혼합성능을 보이는 설계변수의 조합을 제시하였다.

SCR 시스템의 믹서 구조 특성에 따른 유동 혼합 특성에 관한 연구 (The Study on the Effects of Mixer Configurations on Fluid Mixing Characteristics in SCR Systems)

  • 서진원;이규익;오정택;최윤호;이종화;박진일
    • 한국자동차공학회논문집
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    • 제16권6호
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    • pp.192-199
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    • 2008
  • The key issues for the reduction technologies of the exhaust gas from diesel engine being developed are to reduce particulate matters and NOx. The SCR system is known to be one of the most efficient and stable technologies to remove NOx through the mixing of NOx and urea solution. In the present research, the effects of mixer configurations of SCR system have been investigated to enhance the SCR performance. First, a Schlieren technique is employed to visualize the mixing characteristics of urea solution and exhaust gas. The results show that a mixer is essential to obtain proper fluid mixing. In addition, numerical studies have been made to understand the mixing characteristics through the comparison of the mal-distribution index of concentration at the several locations of the diffuser. In particular, the effects of number of blade and mixer angles on mixing characteristics were studied. The results show that the blade angle has a larger effect on the mixing characteristics than the number of blades.

자동차용 토크 컨버터의 수치해석적 연구(Part II) -날개각과 성능- (A Numerical Study on the Automotive Torque Converter(Part II) -Blade Angles and Performances-)

  • 박재인;조강래
    • 한국자동차공학회논문집
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    • 제6권6호
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    • pp.174-184
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    • 1998
  • The situation frequently occurs in which the input torque capacity of the torque converter should be changed. It is known that the modification of the outlet blade angles of the torque converter elements is suitable for such situation with the outer diameter of flow path of the converter maintained. But so far it has been difficult to predict correctly the converter characteristics as well as the effect of outlet angles on torque capacity in the past numerical methods. In the present numerical method introducing the interrow mixing planes, the torque capacity was satisfactorily estimated and it was shown that the torque capacity could be effectively changed by modifying the outlet blade angles of pump and stator.

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정익 후연의 냉각유체분사를 포함한 축류터빈단의 성능해석 (Performance Analysis of an Axial Flow Turbine Stage with Coolant Ejection from Stator Trailing Edge)

  • 김동섭;김재환;노승탁
    • 대한기계학회논문집B
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    • 제23권7호
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    • pp.831-840
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    • 1999
  • In this work, an aerothermodynamic calculation model for cooled axial flow turbine blades with trailing edge ejection is suggested and a mean line performance analysis of a turbine stage with nozzle cooling is carried out. A unique model regarding the interaction between coolant and main gas is proposed, while existing correlations are adopted to predict viscous loss and blade outflow angle. The interactions considered are the heat transfer from main gas to coolant and the temperature and pressure losses by the mixing of two streams due to the trailing edge coolant ejection. For a stator blade without ejection, trailing edge loss calculated by the trailing edge analysis is compared with that calculated by loss correlation. The effect of heat transfer effectiveness of coolant passage on the mixing loss is analyzed. For a model turbine stage with nozzle cooling, parametric analyses are carried out to investigate the effect of main design variables(coolant mass flow ratio, temperature and ejection area) on the stage performance.

전향 스윕 축류형 팬에서의 팁 누설 유동 구조 (Structure of Tip Leakage Flow in a Forward-Swept Axial-Flow Fan)

  • 이공희;백제현
    • 유체기계공업학회:학술대회논문집
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    • 유체기계공업학회 2002년도 유체기계 연구개발 발표회 논문집
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    • pp.131-136
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    • 2002
  • A computational analysis using Reynolds stress model in FLUENT is conducted to give a clear understanding of the effect of blade loading on the structure of tip leakage flow in a forward-swept axial-flow fan at design condition ($\phi$=0.25) and off-design condition ($\phi$=0.21 and 0.30). The roll-up of tip leakage flow starts near the minimum static wall pressure position, and the tip leakage vortex developes along the centerline of the pressure trough within the blade passages. Near tip region, a reverse flow induced by tip leakage vortex has a blockage effect on the through-flow. As a result, high momentum region is observed below the tip leakage vortex. As the blade loading increases, the reverse flow region is more inclined toward circumferential direction and the onset position of the rolling-up of tip leakage flow moves upstream. Because the casing boundary layer becomes thicker, and the mixing between the through-flow and the leakage jet with the different flow direction is enforced, the streamwise vorticity decays more fast with blade loading increasing. The computational results show that a distinct tip leakage vortex is observed downstream of the blade trailing edge at $\phi$=0.30, but it is not observed at $\phi$=0.21 and 0.25.

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블레이드 하중이 축류형 팬에서의 팁 누설 유동구조에 미치는 영향 (Effect of Blade Loading on the Structure of Tip Leakage Flow in a Forward-Swept Axial-Flow Fan)

  • 이공희;명환주;백제현
    • 설비공학논문집
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    • 제15권4호
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    • pp.294-304
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    • 2003
  • An experimental analysis using three-dimensional laser Doppler velocimetry(LDV) measurement and computational analysis using the Reynolds stress model in FLUENT are conducted to give a clear understanding of the effect of blade loading on the structure of tip leakage flow in a forward-swept axial-flow fan operating at the maximum efficiency condition ($\Phi$=0.25) and two off-design conditions ($\Phi$=0.21 and 0.30). As the blade loading increases, the onset position of the rolling-up of tip leakage flow moves upstream and the trajectory of tip leakage vortex center is more inclined toward the circumferential direction. Because the casing boundary layer becomes thicker and the mixing between the through-flow and the leakage jet with the different flow direction is enforced, the streamwise vorticity decays more fast with the blade loading increasing. A distinct tip leakage vortex is observed downstream of the blade trailing edge at $\Phi$=0.30, but it is not observed at $\Phi$=0.21 and 0.25.