• 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.

• 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.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2005년도 창립60주년 기념 추계 학술대회
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• pp.86.1-86.1
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• 2005

• 대한기계학회논문집B
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• 제33권11호
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• pp.900-908
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• 2009

Numerical simulation has been carried out to investigate the influence of radial temperature gradient on the Taylor Vortex flow. Varying the Grashof number, we study the detailed flow and temperature fields. The current numerical results show good agreement with the experimental results currently available. It turns out that wavy spiral vortices are generated by increasing temperature gradient. We classify flow patterns for various Grashof numbers based on the characteristics of flow fields and spiral vortices. The correlation between Grashof number with wave number shows that the spiral angle and size of Taylor vortices increase with increasing temperature gradient. Temperature gradient does not have a great influence on the heat transfer rate of the cylinder surfaces.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2007년도 추계 학술대회논문집
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• pp.127-133
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• 2007

This paper represents the numerical study on Taylor flow according to the radius ratio and the angular velocity for flow between tow cylinder. The numerical model is consisted of two cylinder which inner cylinder is rotating and outer cylinder is fix, and the axial direction is used the cyclic condition because of the length for axial direction is assumed infinite. The diameter of inner cylinder is assumed 86.8 mm, the numerical parameters are angular velocity and radius ratio. The numerical method is compared with the experimental results by Wereley, and the results are very good agreement. The critical Taylor number is calculated by theoretical and numerical analysis, and the results is showed the difference about ${\pm}10\;%$. As $Re/Re_c$ is increased, Taylor vortex is changed to wavy vortex, and then the wave number for azimuthal direction is increased. Azimuthal wave according to the radius ratio is showed high amplitude and low frequence in case of small radius ratio, and is showed low amplitude and high frequence in case of large radius ratio.

• 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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• 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 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.

• 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.

• 한국유체기계학회 논문집
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• 제2권1호
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• pp.103-107
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• 1999

Transient flow inside a hollow shaft of a Gas Turbine engine during sudden engine stop may result in non uniform heat transfer coefficients in the shaft due to flow instability similar to steady Taylor vortex, which may decrease the lifetime of the shaft. In the present study, transient Taylor vortex phenomena inside a suddenly stopped hollow shaft are studied analytically. Flow visualization is also performed to study the shape and onset time of Taylor Vortices for various initial rotational speed.