• Title/Summary/Keyword: Mixing velocity

Search Result 622, Processing Time 0.036 seconds

3-D Dynamic Visualization by Stereoscopic PIV

  • LEE Young-Ho
    • 한국가시화정보학회:학술대회논문집
    • /
    • 2004.12a
    • /
    • pp.15-23
    • /
    • 2004
  • The present study is aimed to achieve dynamic visualization from the in-house 3-D stereoscopic PIV to represent quantitative flow information such as time-resolved 3-D velocity distribution, vorticity, turbulent intensity or Reynolds stresses and so on. One of the application of the present study is Leading edge extension(LEX) flow appearing on modern delta wing aircraft. The other is mixing flow in stirring tank used in industry field. LEX in a highly swept shape applied to a delta wing features the modern air-fighters. The LEX vortices generated upon the upper surface of the wing at high angle of attack enhance the lift force of the delta wing by way of increased negative suction pressure over the surfaces. The present method resolves also the complicated flow patterns of two type impellers rotating in stirring vessel. Flow quantities such as three velocity vector components, vorticity and other flow information can be easily visualized via the 3D time-resolved post-processing visualization. And it makes the easy understanding of the unsteady flow characteristics of the typical industrial mixers.

  • PDF

Sensitivity Analysis of Parameters in a Depth Averaged Two-Dimensional Sediment Transport Model (수심적분 2차원 유사이동모형에 관계된 인자들의 민감도분석에 관한 연구)

  • Seo, Sang-Won;Yun, Byeong-Man
    • Journal of Korea Water Resources Association
    • /
    • v.31 no.1
    • /
    • pp.115-120
    • /
    • 1998
  • In this paper, a depth-averaged two-dimensional transport model is introduced, and its error bound is presented as the results of sensitivity analysis. The results show that the calculated SS concentration is highly dependant on Manning roughness coefficient, mixing coefficient. fall velocity. and critical shear stress. On the other hand, water level and dispersion coefficient are proved to be less significant in the variation of SS concentration.

  • PDF

Numerical Analysis on the Turbulent Mixing Flow Field of $45^{\circ}$ Impinging Round Jet ($45^{\circ}$ 원형충돌분류의 난류혼합유동장에 대한 수치해석)

  • Kim, J.K.;Oh, S.H.
    • Journal of Power System Engineering
    • /
    • v.15 no.3
    • /
    • pp.38-45
    • /
    • 2011
  • The computational flow numerical analysis was introduced to predict thc turbulent characteristics in the mixing flow structure of $45^{\circ}$ impinging round jet. This analysis has been carried out through the commercial fluent software. Realizable(RLZ) k-${\varepsilon}$ was used as a turbulent model. It can be known that mean velocities analysed through RLZ k-${\varepsilon}$ turbulent model comparatively predict well the experiments and show well the elliptic shape of mixing flow structure in the Y-Z plane, but analysed turbulent kinetic energies show somewhat differently from the experiments in certain regions.

Measurement and Analysis on the Mixing Flows in a Tank with a Bottom Agitator using a Hybrid Volume Measurement Technique (하이브리드 볼륨측정법에 의한 하부교반 탱크내 혼합유동 측정 및 해석)

  • Doh, Deog Hee;Lee, Chang Jae;Baek, Tae Sil
    • Journal of the Korean Society of Visualization
    • /
    • v.10 no.3
    • /
    • pp.42-47
    • /
    • 2012
  • Experimental data for the flows in a mixing tank with a bottom agitator are useful for the validation of CFD commercial code. A hybrid volume PIV measurement technique was constructed to measure the flows inside of the mixing tank. The measurement system consists of three cameras. An agitator was installed at the bottom of the tank and it rotates clockwise and counterclockwise. Using the constructed measurement system, instantaneous vector fields were obtained. A phase averaging technique was adopted for the measured instantaneous three-dimensional velocity vector fields. Turbulent properties were evaluated from the instantaneous vector fields.

A Fundamental Study on the Prediction of Carbonation Progress Using Deep Learning Algorithm Considering Mixing Factors (배합인자를 고려한 딥러닝 알고리즘 기반 탄산화 진행 예측에 관한 기초적 연구)

  • Jung, Do-Hyun;Lee, Han-Seung
    • Proceedings of the Korean Institute of Building Construction Conference
    • /
    • 2019.05a
    • /
    • pp.30-31
    • /
    • 2019
  • Carbonation of the root concrete reduces the durability of the reinforced concrete, and it is important to check the carbonation resistance of the concrete to ensure the durability of the reinforced concrete structure. In this study, a basic study on the prediction of carbonation progress was conducted by considering the mixing conditions of concrete using deep learning algorithm during the theory of artificial neural network theory. The data used in the experiment used values that converted the carbonation velocity coefficient obtained from the mixing conditions of concrete and the accelerated carbonation experiment into the actual environment. The analysis shows that the error rate of the deep learning model according to the Hidden Layer is the best for the model using five layers, and based on the five Hidden layers, we want to verify the predicted performance of the carbonation speed coefficient of the carbonation test specimen in which the exposure experiment took place in the real environment.

  • PDF

Numerical Study on Tribrachial Flame Propagation in a 2-D Mixing Layer (연료/산화제의 2차원 혼합층에서 삼지화염의 전파 특성에 관한 수치해석)

  • Kim, Jun-Hong;Kim, Hong-Jip;Chung, Suk-Ho
    • Journal of the Korean Society of Combustion
    • /
    • v.6 no.1
    • /
    • pp.7-13
    • /
    • 2001
  • Propagation characteristics of tribrachial flames have been studied numerically in a two-dimensional fuel/oxidizer mixing layer. A flame is initiated by imposing a high temperature ignition source. Subsequent propagation of a tribrachial flame is traced. The flow redirection effect at the leading edge of a tribrachial flame increases the propagation speed beyond the corresponding stoichiometric laminar burning velocity. The effect of mixture fraction gradient on the propagation speed of a tribrachial flame is analyzed in a mixing layer considering that mixture fraction gradient increases as a tribrachial flame propagates toward upstream. As the flame curvature at the leading edge increases with decreasing mixture fraction gradient, the flow redirection effect becomes more pronounced on the flame propagation speed. As a result, the propagation speed of a tribrachial flame increases with decreasing mixture fraction gradient.

  • PDF

Experimental Study on the Lift-off Behavior of Tone-excited Propane Jet Diffusion flames (음향 가진 된 프로판 확산 화염의 부상 거동에 관한 실험적 연구)

  • Kim, Seung-Gon;Park, Joeng;Kim, Tea-Kwon;Lee, Kee-Man
    • 한국연소학회:학술대회논문집
    • /
    • 2003.05a
    • /
    • pp.65-73
    • /
    • 2003
  • An experimental study on flame lift-off characteristics of propane jet flame highly diluted with nitrogen has been conducted introducing acoustic forcing with a tube resonant frequency. A flame stability curve is attained according to forcing strength and nozzle exit velocity for $N_2$ diluted flames. Flame lift-off behavior with forcing strength and nozzle exit velocity is globally categorized into three; a well premixed behavior caused by a collapsible mixing for large forcing strength, a coexistent behavior of well-premixed and edge flames interacting with well-organized inner fuel vortices for moderate forcing strengths, and edge flame behavior for small forcing strengths. Special focus is concentrated on the coexistent behavior of the flame base in lifted flame since this may give a hint to a possibility which the flame base behaves like a well-mixed premixed flame in highly turbulent lifted flames. It is also shown that the acoustic forcing to self-pulsating laminar lifted flame affects flame lift-off behavior considerably which is closely related to downstream flow velocity, mixture strength, effective fuel Lewis number, and flame stretch.

  • PDF

A Study on the Velocity Distributions and Pressure Distributions in Ejector (Ejector 내의 유동특성에 관한 연구)

  • Lee, Haeng-Nam;Park, Ji-Man;Lee, Duck-Gu
    • Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
    • /
    • 2003.10a
    • /
    • pp.254-259
    • /
    • 2003
  • The Ejector is used to get low pressure, and it has been applied to a lot of industry field like the heat engine, the fluid instrument power plant, the food industry, environment industry etc... because there are not any problem even it is mixed with a any kind of liquid, gas, and solid. The flow characteristics in ejector are investigated by PIV and CFD. The experiment using PIV measurement for mixing pipe’s flow characteristics acquired velocity distribution, .Condition : when mixing pipe’s diameter ratio is 1:1.9, and the flux is $Q_{1}=1.136\;l/s$, $Q_{2}=1.706\;l/s$, $Q_{3}=2.276\;l/s$. Based on the PIV and the CFD results, the flow characteristics in ejector are discussed, and it shows the validity of this study.

  • PDF

Bottom Friction of Surface Waves and Current Flow (천해파와 해류에 의한 해저면 마찰력)

  • 유동훈;김지웅
    • Journal of Korean Society of Coastal and Ocean Engineers
    • /
    • v.12 no.3
    • /
    • pp.130-138
    • /
    • 2000
  • The friction factor equation of open channel flow is developed by using Prandtl's mixing length theory and considering the flow characteristics of smooth or rough turbulent flow. BYO model considers vertical velocity profile for the (:omputation of bottom friction of surface waves and current flow. The model computes the mean bottom friction of combined wave-current flow by the vectorial summation of wave velocity and current velocity at Bijker point. The near bottom flow is discriminated by three flow regimes; smooth, transitional and rough turbulent flow. The model, BYO, has been further refined considering the combination of smooth turbulent flow and rough turbulent flow.

  • PDF

A Numerical Study on Mixing Characteristics for Recess Length of Swirl Coaxial Injector (스월 동축형 분사기의 리세스 길이에 따른 혼합특성에 관한 수치적 연구)

  • Kim, Young-Jun;Hong, Moon-Geun;Lee, Soo-Yong;Sohn, Chae-Hoon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
    • /
    • 2011.11a
    • /
    • pp.74-77
    • /
    • 2011
  • A mixing characteristics on recess length change of Gas-centered swirl coaxial injector using high-performance staged combustion rocket engine carry out study through CFD(Computational fluid dynamics). propellant phase that combined gas-liquid simulate gas-gas. In order to measure spreading angle, velocity distribution to injector exit and spray structure of propellant analyzed. Axial velocity increase by increasing recess length, but tangential velocity decrease. The result confirmed qualitative characteristics that the spreading angle decreases.

  • PDF