Visualization of Dispersed Phase Flow in Centrifugal Extractor Using Taylor-Couette Vortex Flow

2011 ◽  
Author(s):  
Hideharu Takahashi ◽  
Hiroshige Kikura ◽  
Kenji Takeshita ◽  
Masanori Aritomi
Keyword(s):  
Flow Field ◽  
Vortex Flow ◽  
Flow Characteristics ◽  
Metal Extraction ◽  
Dispersed Phase ◽  
Cylinder Surface ◽  
Centrifugal Extractor ◽  
Hydrophobic Coating ◽  
Measurement And Analysis ◽  
Taylor Couette

For studying the designs and running operations of an extractor which uses Taylor-Couette vortex flow, we focused on a metal extraction system as one of the extraction models of heat generating nuclides and observed the flow patterns of dispersed phase by dyeing the phase in the extractor, and we investigated the effects of hydrophobic coating applied to the inner cylinder surface on the flow characteristics. Moreover, for the quantitative measurement and analysis of the flow field, we evaluated the applicability of Ultrasonic Velocity Profiler (UVP) to flow field measurement. Thorough these visualization methods of dispersed phase in a centrifugal extractor using Taylor-Couette vortex flow, we examined the relation between flow field and extraction characteristics of the extractor.

scholarly journals Space–time VMS isogeometric analysis of the Taylor–Couette flow

2021 ◽  
Vol 67 (5) ◽  
pp. 1515-1541
Author(s):  
Levent Aydinbakar ◽  
Kenji Takizawa ◽  
Tayfun E. Tezduyar ◽  
Takashi Kuraishi
Keyword(s):  
Flow Field ◽  
Couette Flow ◽  
Vortex Flow ◽  
Computational Analysis ◽  
Reynolds Numbers ◽  
High Fidelity ◽  
Exact Representation ◽  
Taylor Couette ◽  
Isogeometric Discretization ◽  
Taylor Couette Flow

AbstractThe Taylor–Couette flow is a classical fluid mechanics problem that exhibits, depending on the Reynolds number, a range of flow patterns, with the interesting ones having small-scale structures, and sometimes even wavy nature. Accurate representation of these flow patterns in computational flow analysis requires methods that can, with a reasonable computational cost, represent the circular geometry accurately and provide a high-fidelity flow solution. We use the Space–Time Variational Multiscale (ST-VMS) method with ST isogeometric discretization to address these computational challenges and to evaluate how the method and discretization perform under different scenarios of computing the Taylor–Couette flow. We conduct the computational analysis with different combinations of the Reynolds numbers based on the inner and outer cylinder rotation speeds, with different choices of the reference frame, one of which leads to rotating the mesh, with the full-domain and rotational-periodicity representations of the flow field, with both the convective and conservative forms of the ST-VMS, with both the strong and weak enforcement of the prescribed velocities on the cylinder surfaces, and with different mesh refinements. The ST framework provides higher-order accuracy in general, and the VMS feature of the ST-VMS addresses the computational challenges associated with the multiscale nature of the flow. The ST isogeometric discretization enables exact representation of the circular geometry and increased accuracy in the flow solution. In computations where the mesh is rotating, the ST/NURBS Mesh Update Method, with NURBS basis functions in time, enables exact representation of the mesh rotation, in terms of both the paths of the mesh points and the velocity of the points along their paths. In computations with rotational-periodicity representation of the flow field, the periodicity is enforced with the ST Slip Interface method. With the combinations of the Reynolds numbers used in the computations, we cover the cases leading to the Taylor vortex flow and the wavy vortex flow, where the waves are in motion. Our work shows that all these ST methods, integrated together, offer a high-fidelity computational analysis platform for the Taylor–Couette flow and for other classes of flow problems with similar features.

Thermo-flow characteristics and air flow field leading of the air-cooled condenser cell in a power plant

2011 ◽  
Vol 54 (9) ◽  
pp. 2475-2482 ◽  
Author(s):  
WanXi Zhang ◽  
LiJun Yang ◽  
XiaoZe Du ◽  
YongPing Yang
Keyword(s):  
Power Plant ◽  
Flow Field ◽  
Air Flow ◽  
Flow Characteristics

scholarly journals Study on the 3D Hydrodynamic Characteristics and Velocity Uniformity of a Gravity Flow Circular Flume

Water ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 927
Author(s):  
Yi Zhang ◽  
Longxi Han ◽  
Lina Chen ◽  
Chenfang Wang ◽  
Bo Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Environmental Science ◽  
Structural Characteristics ◽  
Longitudinal Velocity ◽  
Flow Characteristics ◽  
Science Research ◽  
Hydrodynamic Characteristics ◽  
Straight Channel ◽  
Uniformity Coefficient ◽  
Annular Flume

Flumes have been widely used in water conservancy science and environmental science research. It is of great significance to obtain the hydrodynamic characteristics and flow field uniformity in the flume. In this study, a new type of annular flume was taken as an example. The 3D flow field was simulated by using a commercial computational fluid dynamics (CFD) code, and was also measured by acoustic doppler velocimeter (ADV) to verify the simulation results. The average relative error range was between 8.37% and 9.95%, the simulated results basically reflected the actual situation of the flow field. On this basis, the structural characteristics of flow field were analyzed. A new calculation method of flow velocity uniformity was presented according to the flow characteristics of natural open channels. The velocity uniformity in the straight channel was calculated and analyzed based on this method, and the influence of speed on the velocity uniformity was further discussed. The length of uniform section was negatively correlated with the rotational speed (average velocity), which was between 39 cm and 101 cm in the straight, and the uniformity coefficient was less than 10%. Finally, the water flow characteristics in the straight channel without wheel were compared with the natural open channel flow. The longitudinal velocity was well fitted with the Prandtl logarithmic distribution formula (R2 > 0.977), and the application feasibility of the flume was analyzed. This study can provide technical support for the development and application of annular flume.

Tip Leakage Flow Characteristics Downstream of an Axial Flow Fan

1996 ◽  
Author(s):  
P. Puddu
Keyword(s):  
Vortex Flow ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Axial Flow ◽  
Tip Leakage Flow ◽  
Single Wire ◽  
Vortex System ◽  
Tip Leakage ◽  
Stress Components ◽  
Computer Controlled

The three-dimensional viscous flow characteristics and the complex vortex system downstream of the rotor of an industrial exial fan have been determined by an experimental investigation using hot-wire anemometer. Single-wire slanted and straight type probes have been rotated about the probe axis using a computer controlled stepper motor. Measurements have been taken at four planes behind the blade trailing edge. The results show the characteristics of the relative flow as velocity components, secondary flow and kinetic energy defect. Turbulence intensity and Reynolds stress components in the leakage vortex area are also presented. The evolution of the leakage vortex flow during the decay process has also been evaluated in terms of dimension, position and intensity.

Effects of Valve Disc on Flow Characteristics Inside a Swing Check Valve During Opening and Closing Processes

2021 ◽  
Author(s):  
Yi-xiang Xu ◽  
Qiang Ru ◽  
Huai-yu Yao ◽  
Zhi-jiang Jin ◽  
Jin-yuan Qian
Keyword(s):  
Flow Field ◽  
Working Conditions ◽  
Power Plants ◽  
Flow Characteristics ◽  
Check Valve ◽  
Opening Angle ◽  
Piping System ◽  
Total Moment ◽  
Valve Disc ◽  
Opening And Closing

Abstract The check valve is one of the most important devices for safety protection of the piping system in thermal and nuclear power plants. As the key component of the check valve, the valve disc accounts for a major effect on the flow characteristics especially during the opening and closing processes. In this paper, a typical swing check valve is taken as the research object. In order to make a comparative study, three working conditions of 30% THA (Turbine Heat Acceptance), 50% THA and 100% THA are selected. Focusing on the effects of valve disc, how does the valve disc motion interact with the flow field around the valve disc is analyzed with the help of the dynamic mesh technology. The results show that under the combined action of fluid force and gravity, the check valve can be opened and closed quickly. During the opening process, the maximum total moment of the disc appears between 45° ∼ 50° opening angle, and during the closing process the maximum total moment occurs when the disc fully closed. The flow field near the valve disc has similar variation rules with the rotation of the valve disc in the three working conditions, and the pressure near the valve disc reaches the maximum value at the moment of opening and closing. This study can provide some suggestions for the further optimal design of similar swing check valve.

Numerical investigation of supercritical Taylor-vortex flow for a wide gap

1984 ◽  
Vol 138 ◽  
pp. 21-52 ◽  
Author(s):  
H. Fasel ◽  
O. Booz
Keyword(s):  
Flow Field ◽  
Vortex Flow ◽  
Numerical Solutions ◽  
Stokes Equations ◽  
Taylor Number ◽  
Taylor Vortex ◽  
Plane Boundary ◽  
Aspect Ratios ◽  
Taylor Vortex Flow ◽  
Wide Gap

For a wide gap (R1/R2= 0.5) and large aspect ratiosL/d, axisymmetric Taylor-vortex flow has been observed in experiments up to very high supercritical Taylor (or Reynolds) numbers. This axisymmetric Taylor-vortex flow was investigated numerically by solving the Navier–Stokes equations using a very accurate (fourth-order in space) implicit finite-difference method. The high-order accuracy of the numerical method, in combination with large numbers of grid points used in the calculations, yielded accurate and reliable results for large supercritical Taylor numbers of up to 100Tac(or 10Rec). Prior to this study numerical solutions were reported up to only 16Tac. The emphasis of the present paper is placed upon displaying and elaborating the details of the flow field for large supercritical Taylor numbers. The flow field undergoes drastic changes as the Taylor number is increased from just supercritical to 100Tac. Spectral analysis (with respect toz) of the flow variables indicates that the number of harmonics contributing substantially to the total solution increases sharply when the Taylor number is raised. The number of relevant harmonics is already unexpectedly high at moderate supercriticalTa. For larger Taylor numbers, the evolution of a jetlike or shocklike flow structure can be observed. In the axial plane, boundary layers develop along the inner and outer cylinder walls while the flow in the core region of the Taylor cells behaves in an increasingly inviscid manner.

Numerical Study of Winglet at Low Reynolds Numbers

2013 ◽  
Author(s):  
Sina Pooladsanj ◽  
Mehran Tadjfar
Keyword(s):  
Aspect Ratio ◽  
Flow Field ◽  
Vortex Flow ◽  
Numerical Study ◽  
Reynolds Numbers ◽  
Flow Zone ◽  
Low Reynolds Numbers ◽  
Structured Grid ◽  
Flow Field Characteristics ◽  
Wing Aspect Ratio

A numerical study has been performed to evaluate the aerodynamics coefficients of a winglet in the range of Reynolds numbers below 30,000. In this study some parameters on winglet design have been considered. The effect of winglet-tip airfoil thickness has been investigated on aerodynamics coefficients. In order to explore this effect, two different airfoils (NACA0002 and NACA0012) were employed at the winglet-tip. The influence of varying the winglet connection angle to the wing on aerodynamics coefficients and flow field characteristics in the vortex flow zone such as; circulation magnitude and vorticity magnitude in the vortex core have been studied. Six connection angles including 20°, 30°, 40°, 50°, 60° and 70° have been studied. Negative values of these angles have also been considered. In addition, the effect of changing wing aspect ratio on aerodynamics coefficients has been investigated. To solve the flow field around the studied geometry a fully structured grid was used which consists of 84 blocks.

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