• Title, Summary, Keyword: Taylor vortex flow

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Three-dimensional Fluid Flow Analysis in Taylor Reactor Using Computational Fluid Dynamics (CFD를 이용한 테일러 반응기의 3차원 유동해석)

  • Kwon, Seong Ye;Lee, Seung-Ho;Jeon, Dong Hyup
    • Applied Chemistry for Engineering
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    • v.28 no.4
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    • pp.448-453
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    • 2017
  • We conducted the three-dimensional fluid flow analysis in a Taylor reactor using computational fluid dynamics (CFD). The Taylor flow can be categorized into five regions according to Reynolds number, i.e., circular Couette flow (CCF), Taylor vortex flow (TVF), wavy vortex flow (WVF), modulated wavy vortex flow (MWVF), and turbulent Taylor vortex flow (TTVF), and we investigated the flow characteristics at each region. For each region, the shape, number and length of vortices were different and they influenced on the bypass flow. As a result, the Taylor vortex was found at TVF, WVF, MWVF and TTVF regions. The highest number of Taylor vortex was observed at TVF region, while the lowest at TTVF region. The numerical model was validated by comparing with the experimental data and the simulation results were in good agreement with the experimental data.

On the Structures of Taylor Vortices. (Taylor Vortex의 구조에 대한 연구)

  • Hwang, Jong-Yeon;Yang, Kyung-Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.27 no.8
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    • pp.1081-1088
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    • 2003
  • Numerical investigation on the structures of various Taylor vortices induced in the flow between two concentric cylinders, with the inner one rotating and with a pressure-driven axial flow imposed, is carried out, and compared with the experiments of Wereley and Lueptow [Phys. fluid, 11(12), 1999] who studied the Taylor vortices using PIV in detail. Especially, the properties of helical vortices and random wavy vortices are discussed, and their three-dimensional structures are visualized using the numerical data. Our simulation also predicts that random wavy vortices have quasi-periodic movement which can be explained by traveling waves formed in the azimuthal direction. The numerical results are well consistent with the experimental findings of Wereley and Lueptow.

Effect of sinusoidal Taylor vortex flow on cooling crystallization of L-lysine

  • Nguyen, Anh-Tuan;Kim, Woo-Sik
    • The Korean Journal of Chemical Engineering
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    • v.34 no.7
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    • pp.1896-1904
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    • 2017
  • An elliptical Couette-Taylor (ECT) crystallizer with a unique sinusoidal Taylor vortex flow was developed to promote the recovery and size distribution of L-lysine crystals in cooling crystallization. When using the ECT crystallizer, the recovery was enhanced to a maximum of 100% with a mean residence time of only 15 min. When comparing the crystallization efficiency, the recovery and size distribution of the L-lysine crystals in the ECT crystallizer were over 33% and 50% higher, respectively, than those in the conventional MSMPR crystallizer and slightly higher than those in the circular Couette-Taylor (CT) crystallizer. This improved crystallization in the ECT crystallizer was explained in terms of the sinusoidal profile of the Taylor vortex intensity. Plus, since the nucleation and growth processes determine the recovery and crystal size distribution, the mean residence time, inner cylinder rotation speed, and feed concentration were all varied to investigate their influence on the crystallization efficiency.

Numerical Study of Radial Temperature Gradient Effect on Taylor Vortices (반경방향으로의 온도구배가 Taylor Vortex에 미치는 영향에 대한 수치적 연구)

  • Kang, Chang-Woo;Yang, Kyung-Soo;Yoon, Dong-Hyeog
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.33 no.11
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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.

Numerical Study of Wavy Taylor-Couette Flow(I) -Without an Axial Flow- (Wavy Taylor-Couette 유동에 대한 전산해석 (I) -축방향 유동이 없는 경우-)

  • Hwang, Jong-Yeon;Yang, Gyeong-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.5
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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.

Transient Flow Instability inside a Gas Turbine Shaft (가스 터빈 축 내부의 비정상 유동의 불안정성)

  • Hur, Nahm-Keon;Won, Chan-Shik
    • The KSFM Journal of Fluid Machinery
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    • v.2 no.1
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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.

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Numerical Studies of Flow Characteristics and Particle Residence Time in a Taylor Reactor (테일러 반응기의 유동특성과 입자 체류시간에 관한 수치적 연구)

  • Lee, Hyeon Kwon;Lee, Sang Gun;Jeon, Dong Hyup
    • Applied Chemistry for Engineering
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    • v.26 no.1
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    • pp.67-73
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    • 2015
  • Using a computational fluid dynamics technique, the flow characteristics and particle residence time in a Taylor reactor were studied. Since flow characteristics in a Taylor reactor are dependent on the operating conditions, effects of the inlet flow velocity and reactor rotational speed were investigated. In addition, the particle residence time of $LiNiMnCoO_2$ (NMC), which is a cathode material in lithium-ion battery, is estimated in the Taylor vortex flow (TVF) region. Without considering the complex chemical reaction at the inlet, the effect of Taylor flow was studied. The results show that the particle residence time increases as the rotating speed increased and the flow rate decreased.

Experimental Study of Axial Slit Wall Effect on Taylor-Couette Flow (축방향 홈이 있는 Taylor-Couette 유동의 실험적 연구)

  • Lee, Sang-Hyuk;Kim, Hyoung-Bum
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.31 no.10
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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.

Experimental study of axial slit wall effect on Taylor-Couette flow (슬릿이 있는 Taylor-Couette 유동의 실험적 연구)

  • Lee, Sang-Hyuk;Kim, Hyoung-Bum
    • Proceedings of the KSME Conference
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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.

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Study of Different Radial Temperature Gradient Effect on Taylor-Couette Flow Instability (온도구배가 Taylor-Couette유동의 불안정성에 주는 영향에 관한 연구)

  • Cha, Jae-Eun;Liu, Dong;Tu, Xin Cheng;Kim, Hyoung-Bum
    • Journal of the Korean Society of Visualization
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    • v.8 no.3
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    • pp.35-40
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    • 2010
  • We have investigated different radial temperature gradient effect on the stability of Taylor-Couette flow. The radius ratio and aspect ratio of the model was 0.825 and 48, respectively. Two heating exchangers were used for generating different temperature gradient along the radial direction. The change of flow regime in the Taylor-Couette flow was studied by increasing the Reynolds number. The results showed that: as Gr is increased in helical vortex flow regime, the vortices with the same direction of convection flow increased in size, and the vortex moving velocity also increased. It is also shown that the presence of temperature gradient obviously increased the flow instability when the Richardson number is larger than 0.0045.