• 대한기계학회논문집B
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• 제25권5호
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• pp.697-704
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• 2001

The flow between two concentric cylinders, with the inner one rotating, is studied using numerical simulation. This study considers the identical flow geometry as in the experiments of Wereley and Lueptow[J. Fluid Mech., 364, 1998]. They carried out experiment using PIV to measure the velocity fields in a meridional plane of the annulus in detail. When Taylor number increases over the critical one, the flow instability caused by curved streamlines of the tangential flow induces Taylor vortices in the flow direction. As Taylor number further increases over another critical one, the steady Taylor vortices become unsteady and non-axisymmetrically wavy. The velocity vector fields obtained also show the same flow features found in the experiments of Wereley and Lueptow.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3183-3186
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• 2007

Taylor-Couette flow may appear when the angular velocity is different between two concentric rotating cylinders. This kind of Taylor-vortex flow can be easily seen in lots of engineering problems. In general the geometries of rotating cylinders are generally complex in these cases. In this study, we investigated Taylor-Couette flow when the outer cylinder has the slit along the annulus. The radius ratio and aspect ratio of the experimental model used was 0.825 and 48, respectively. The depth of slits is 5mm and total 18 slits are azimuthally located along the inner wall of outer cylinder. We used PIV method to measure the flow and applied index matching method to resolve the complex geometry effect. The results show the model with slit has no stable wavy vortex region above Re=143.

• 대한기계학회논문집B
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• 제31권10호
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• pp.889-894
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• 2007

The effect of the axial slit of outer cylinder on Taylor-Couette flow was experimentally investigated. The radius ratio and aspect ratio of the model was 0.825 and 48, respectively. The depth of slits was 5mm and total 18 slits were azimuthally located along the inner wall of outer cylinder. We used PIV method to measure the flow field and applied refractive index matching method to resolve the image distortion due to the complex model geometry. The results showed the axial slit did not affect the transition from laminar Couette flow to Taylor vortex. The effect of slit wall appeared when the Reynolds number is larger than Re=143 and the slit model shows the transition to turbulent Taylor vortex flow above Re=143.

• 공업화학
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• 제26권1호
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• pp.67-73
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• 2015

전산유체해석 기법을 이용하여, 테일러 반응기 내 유동특성과 입자의 체류시간에 대하여 연구하였다. 테일러 반응기는 반응기의 작동조건에 따라 내부 유동특성이 달라지므로, 입구주입속도와 반응기 회전속도 변화에 따른 테일러 반응기 내부의 유동특성 변화를 살펴보았다. 또한 테일러 와류(TVF)영역에서 리튬이온전지의 양극물질인 NMC입자의 반응기 내 체류시간을 측정하였다. 입구에서의 복잡한 화학반응은 고려하지 않았고 테일러 유동의 영향만 고찰하였다. 해석결과 반응기의 회전속도가 높고 반응물의 주입속도가 낮을수록 입자의 체류시간이 길어지는 것을 확인하였다.

• 공업화학
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• 제28권4호
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• pp.448-453
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• 2017

테일러 반응기에서 일어나는 유동의 변화를 전산유체역학을 이용하여 3차원 유동해석을 수행하였다. 테일러 유동은 레이놀즈 수의 증가에 따라 5개의 영역(순환 쿠에트 유동(CCF), 테일러 와류 유동(TVF), 물결 와류 유동(WVF), 변조 물결 와류 유동(MWVF), 난류 테일러 와류 유동(TTVF))으로 나뉘어지며, 각각의 영역에서의 유동 특성을 알아보았다. 각각의 영역에서 와류의 형상, 개수, 길이 등에 차이를 나타나며 바이패스 흐름에도 영향을 줌을 확인하였다. 그 결과 TVF, WVF, MWVF, TTVF 영역에서 테일러 와류가 발생하였다. 테일러 와류의 개수는 TVF 영역에서 가장 많으며 TTVF 영역에서 가장 적게 관찰되었다. 수치해석모델의 검증을 위하여 실험결과와 비교하였고, 실험결과 대비 해석결과가 잘 일치함을 나타내었다.

• 대한기계학회논문집B
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• 제25권5호
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• pp.705-712
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• 2001

The flow between two concentric cylinders, with the inner one rotating and with an imposed pressure-driven axial flow, is studied using numerical simulation. The case without the axial flow was investigated in the preceding paper. This study considers the identical flow geometry as in the experiments of Wereley and Lueptow[Phys. Fluid, 11(12), 1999]. They carried out experiments using PIV to measure the velocity fields in a meridional plane of the annulus in detail. When an axial flow is imposed, the critical Taylor number is increased. The axial flow stabilizes the flow field and decreases the torque required to rotate the inner cylinder. The velocity vector fields obtained also show the same flow features found in the experiments of Wereley and Lueptow.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.444-449
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• 2001

The flow between two concentric cylinders, with the inner one rotating and with an imposed pressure-driven axial flow, is studied using numerical simulation. This study considers the identical flow geometry as in the experiments of Wereley and Lueptow[Phys. Fluid, 11 (12), 1999]. They carried out experiments using PIV to measure the velocity fields in a meridional plane of the annulus in detail. When an axial flow is imposed, the critical Taylor number is increased. The axial flow stabilizes the flow field and decreases the torque required to rotate the inner cylinder. The velocity vector fields obtained also show the same flow features found in the experiments of Wereley and Lueptow.

• 한국전산유체공학회지
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• 제15권4호
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• pp.32-39
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• 2010

In this study, we consider Taylor-Couette flow with the outer cylinder at rest and the inner one oscillating with a mean angular velocity. Varying the mean angular velocity, amplitude and frequency of the oscillation, we investigate the characteristics of modulated Taylor vortices. At a constant mean angular velocity, Taylor vortices intensify as the amplitude increases and frequency decreases. The axial wavenumber is calculated by spectral analysis. When the frequency varies, the axial wavenumber does not change at a constant mean angular velocity and amplitude. But, the axial wavenumber increases, as the mean angular velocity increases.

• 대한기계학회논문집B
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• 제25권3호
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• pp.373-380
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• 2001

In this study, a single Taylor bubble and a train of Taylor bubbles rising in a vertical tube were simulated numerically. A finite difference method was used to solve the mass and momentum equations for the liquid-gas region. The liquid-gas interface was captured by a level set function which is defined a signed distance from the interface. For a train of Taylor bubbles repeated periodically in space, the periodic conditions were imposed at the boundaries normal to the gravitational direction and the pressure boundary conditions were iteratively determined so that the computed flow rate should be equal to a given flow rate. Based on the numerical simulation, the calculated shape and rise velocity of a Taylor bubble were found to be in good agreement with the experimental data reported in the literature.

• 한국전산유체공학회지
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• 제14권3호
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• pp.95-105
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• 2009

We study time-periodic Taylor-Couette flow with the outer cylinder at rest and the inner one oscillating with a mean angular velocity. Varying the frequency of inner cylinder, we investigate the change of Taylor vortices at a given amplitude and a mean angular velocity. With a small frequency of modulation, we find that Taylor vortices appear and disappear periodically. With a higher frequency, Taylor vortices do not disappear, but the intensity of Taylor vortices modulates periodically. As the frequency increases, Taylor vortices modulate harmonically.