Numerical Simulation of Fluid Flow in a New High Efficient Mixer

2012 ◽  
Vol 251 ◽  
pp. 226-230
Author(s):  
Qing Wu ◽  
Ya Chen Zhang ◽  
Xue Jun Liu ◽  
Bao An Han
Keyword(s):  
Fluid Flow ◽  
Flow Direction ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Computational Results ◽  
Static Mixer ◽  
Turbulent Model ◽  
Mixing Effect ◽  
High Efficient ◽  
Processing Software

In order to determine proper structural parameters of the new high efficient mixer created by the author, the CFD software is applied to simulate numerically three dimensional incompressible turbulent fields for three static mixing units and the mixing unit with rotating impellor. The static mixing units include three kinds of spiral blades that are single-blade style, three-blade style and four-blade style. Geometric models are built by Pro/ENGINEER and exported to Fluent. The time-mean Reynolds equations and standard turbulent model are applied, and the post-processing software is used to analyze the computational results, and velocity contours and stress contours of mixing fluids in the static mixer will be obtained. The computational results indicate that the direction of outlet velocity of three-blade fluid flow turns more dramatically in comparison with that of single-blade and four-blade fluid flow, and the shearing stress is more remarkable. Because the internal stress of three-blade fluid changes more, the mixing action among fluids is more intensified. All these show three-blade spiral blades have the best mixing effects for local fluids. The rotating impellor mounted between blades can change fluid flow direction and improve the mixing effect for local fluids, which is moved by fluid flow with some velocity.

Mobile GPU Computing Based Filter Bank Convolution for Three-Dimensional Wavelet Transform

2016 ◽  
Vol 7 (2) ◽  
pp. 22-35
Author(s):  
Di Zhao
Keyword(s):  
Wavelet Transform ◽  
Discrete Wavelet Transform ◽  
Real Time ◽  
Gpu Computing ◽  
Three Dimensional ◽  
Discrete Wavelet ◽  
Computational Results ◽  
Time Processing ◽  
Mobile Gpu ◽  
High Efficient

Mobile GPU computing, or System on Chip with embedded GPU (SoC GPU), becomes in great demand recently. Since these SoCs are designed for mobile devices with real-time applications such as image processing and video processing, high-efficient implementations of wavelet transform are essential for these chips. In this paper, the author develops two SoC GPU based DWT: signal based parallelization for discrete wavelet transform (sDWT) and coefficient based parallelization for discrete wavelet transform (cDWT), and the author evaluates the performance of three-dimensional wavelet transform on SoC GPU Tegra K1. Computational results show that, SoC GPU based DWT is significantly faster than SoC CPU based DWT. Computational results also show that, sDWT can generally satisfy the requirement of real-time processing (30 frames per second) with the image sizes of 352×288, 480×320, 720×480 and 1280×720, while cDWT can only obtain read-time processing with small image sizes of 352×288 and 480×320.

Comparison of CFD Simulation to the Experiments for Forward Step Flows

2003 ◽  
Author(s):  
Shoichiro Nakamura ◽  
Hiroyuki Onuma ◽  
Peter G. Carswell
Keyword(s):  
Fluid Flow ◽  
Vortex Shedding ◽  
Cfd Simulation ◽  
Computational Simulation ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Unsteady Motion ◽  
Computational Results ◽  
Over The Top ◽  
Unsteady Behavior

Three dimensional DNS simulation on the fluid flow over a forward step configuration are compared with the experiments reported by Shakouchi, Ando, and Ito. This is a part of authors’ attempts to evaluate the validity of three dimensional unsteady flow simulation by comparison to experiments. Summary of the comparison is as follows: (1) vortex shedding in the flow separation over the top of the step near the corner is observed, (2) frequency of vortex shedding and distance between two consecutive vortices do not agree with the experiment, (3) however, while steady periodic shedding of vortices from the top corner of the step is reported for the experimental results, the computational results show unsteady behavior of the flow over the top corner, which results in unsteady shedding of vortices. This unsteadiness in the computational simulation is due to unsteady motion of fluid upstream from the step where adverse pressure increase occurs.

Optimization of Six Strand Tundish Based on Flow and Temperature

2011 ◽  
Vol 239-242 ◽  
pp. 1846-1849
Author(s):  
Sheng Li Li ◽  
Xin Gang Ai ◽  
Dong Wei Zhang ◽  
Nan Lv ◽  
Xiao Dong Hu
Keyword(s):  
Fluid Flow ◽  
Physical Modeling ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Fluid Flows ◽  
Temperature Fields

In this paper the fluid flow and temperature are used together to optimize the 40 tons six strand tundish. Fluid flows in a six strand tundish have been investigated with physical modeling, then steady, three-dimensional temperature fields inside the six strand tundish are obtained. The physical modeling experiments give two optimal integrated tundish structural parameters of baffle holes. From the further study of temperature fields, the tundish should be optimized in the structural parameters of baffle holes in the condition of height 300mm, angel 30° and diameter 20mm.

A Study on Characteristics of Fluid Flow and Mixing in a Microchannel With a Controlled Local Electric Field

2006 ◽  
Author(s):  
Hyeung Seok Heo ◽  
Yong Kweon Suh ◽  
Sang Mo Kang
Keyword(s):  
Fluid Flow ◽  
Electric Field ◽  
Three Dimensional ◽  
Metal Electrode ◽  
Rotational Flow ◽  
Metal Electrodes ◽  
Mixing Index ◽  
Mixing Effect ◽  
Commercial Code ◽  
Parameter Values

In this study a newly designed microchannel is proposed. This design is comprised of a channel and a series of metal electrodes periodically attached on the both side’s surfaces of the channel. In this configuration, the mixing effect is greatly enhanced at a certain parameter values. To characterize the flow field and the mixing effect, both numerical and experimental methods were employed. To obtain the potential field, electric field, and velocity vectors three-dimensional numerical computation was performed by using a commercial code, CFD-ACE+. The fluid-flow solutions were then cast into studying the characteristics of stirring with the aid of mixing index. In this study the mixing index were computed manually because the commercial code does not provide the corresponding tool. In the experiment, flow visualization was performed by using water with fluorescent particles. The numerical results show that the velocity pattern in the microchannel heavily depends on the metal electrodes arrangement on both sides. It was shown that the rotational flow is significantly enhanced by a higher voltage of metal electrode.

3D FRACTAL DIMENSION AND FLOW PROPERTIES IN THE PORE STRUCTURE OF GEOLOGICAL ROCKS

Fractals ◽  
2011 ◽  
Vol 19 (03) ◽  
pp. 291-297 ◽  
Author(s):  
SELLY FERANIE ◽  
UMAR FAUZI ◽  
SATRIA BIJAKSANA
Keyword(s):  
Image Analysis ◽  
Fractal Dimension ◽  
Fluid Flow ◽  
Pore Structure ◽  
Flow Direction ◽  
Three Dimensional ◽  
Serial Sectioning ◽  
Flow Properties ◽  
Rock Samples ◽  
Box Counting

Three-dimensional pore structure of four samples of geological rock was obtained using serial sectioning. Their fractal and flow properties have been successfully determined through image analysis. The measured 3D box counting fractal dimension of four geological rock samples are 2.59, 2.88, 2.88 and 2.29, which are not integer dimensions. This would imply that the structure of the four geological rock samples is fractal in nature. Porosity of the four rock samples are ranged from 0.18 to 0.31 and the specific surface area is ranged from 1.57 to 2.75 mm-1. Tortuosity estimated from image analysis of the four samples is ranged from 1.11 to 5.83 and varied in each fluid flow direction. This would imply that the rock samples are not uniform in its pore structure. The fractal dimension as a representation of the isotropic level of the pore structure is not clearly clarified and it still needs further investigation.

scholarly journals Numerical Simulations of Three-Dimensional Fluid Flow and Coupled Heat Transfer in Bipolar Plates

2007 ◽  
Author(s):  
Jianfei Wu ◽  
Jianhu Nie ◽  
Yitung Chen
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Fluid Flow ◽  
Numerical Simulations ◽  
Three Dimensional ◽  
Electrolysis Cell ◽  
Bipolar Plates ◽  
Coupled Heat Transfer ◽  
High Efficient ◽  
Pem Electrolysis

Bipolar plate is one of the key components in PEM electrolysis cell stacks, and it performs a number of essential functions in stack operation, such as reactant supply to the cell active area, current collection, and mechanical support to the MEA. High efficient PEM electrolysis cell stacks will require optimized bipolar plates. Improvements in the design of bipolar plates can help achieve the set goals of cost and performance for the PEM electrolysis cell. In the present work, numerical simulations were performed for three-dimensional fluid flow and coupled heat transfer in bipolar plates. The Reynolds number of inlet flow is varied from 100 to 900 on the anode side while the Reynolds number is maintained as a constant of 100. The solid wall surfaces of the bipolar plates are assumed to be adiabatically insulated, except that the active areas of the channels are supplied with uniform heat flux. Results of velocity and temperature distributions for different Reynolds numbers will be presented and discussed.

Experiments and mechanistic modeling of viscosity effect on a multistage ESP performance under viscous fluid flow

2021 ◽  
pp. 095765092110149
Author(s):  
Yi Shi ◽  
Jianjun Zhu ◽  
Haoyu Wang ◽  
Haiwen Zhu ◽  
Jiecheng Zhang ◽  
...  
Keyword(s):  
Fluid Flow ◽  
Viscous Fluid ◽  
Prediction Error ◽  
Flow Direction ◽  
Fluid Viscosity ◽  
Oil Viscosity ◽  
Viscous Fluid Flow ◽  
Viscosity Effect ◽  
High Production Rate ◽  
Pump Head

Assembled in series with multistage, Electrical Submersible Pumps (ESP) are widely used in offshore petroleum production due to the high production rate and efficiency. The hydraulic performance of ESPs is subjected to the fluid viscosity. High oil viscosity leads to the degradation of ESP boosting pressure compared to the catalog curves under water flow. In this paper, the influence of fluid viscosity on the performance of a 14-stage radial-type ESP under varying operational conditions, e.g. rotational speeds 1800–3500 r/min, viscosities 25–520 cP, was investigated. Numerical simulations were conducted on the same ESP model using a commercial Computational Fluid Dynamics (CFD) software. The simulated average pump head is comparable to the corresponding experimental data under different viscosities and rotational speeds with less than ±20% prediction error. A mechanistic model accounting for the viscosity effect on ESP boosting pressure is proposed based on the Euler head in a centrifugal pump. A conceptual best-match flowrate QBM is introduced, at which the impeller outlet flow direction matches the designed flow direction. The recirculation losses caused by the mismatch of velocity triangles and other head losses resulted from the flow direction change, friction loss and leakage flow etc., are included in the model. The comparison of model predicted pump head versus experimental measurements under viscous fluid flow conditions demonstrates good agreement. The overall prediction error is less than ±10%.

scholarly journals Brain capillary structures of schizophrenia cases and controls show a correlation with their neuron structures

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Rino Saiga ◽  
Masayuki Uesugi ◽  
Akihisa Takeuchi ◽  
Kentaro Uesugi ◽  
Yoshio Suzuki ◽  
...  
Keyword(s):  
Blood Vessels ◽  
Structural Parameters ◽  
Three Dimensional ◽  
Superior Temporal Gyrus ◽  
Anterior Cingulate ◽  
Dimensional Structure ◽  
Constant Diameter ◽  
The Mean ◽  
Cartesian Coordinate ◽  
Micrometer Scale

AbstractBrain blood vessels constitute a micrometer-scale vascular network responsible for supply of oxygen and nutrition. In this study, we analyzed cerebral tissues of the anterior cingulate cortex and superior temporal gyrus of schizophrenia cases and age/gender-matched controls by using synchrotron radiation microtomography or micro-CT in order to examine the three-dimensional structure of cerebral vessels. Over 1 m of cerebral blood vessels was traced to build Cartesian-coordinate models, which were then used for calculating structural parameters including the diameter and curvature of the vessels. The distribution of vessel outer diameters showed a peak at 7–9 μm, corresponding to the diameter of the capillaries. Mean curvatures of the capillary vessels showed a significant correlation to the mean curvatures of neurites, while the mean capillary diameter was almost constant, independent of the cases. Our previous studies indicated that the neurites of schizophrenia cases are thin and tortuous compared to controls. The curved capillaries with a constant diameter should occupy a nearly constant volume, while neurons suffering from neurite thinning should have reduced volumes, resulting in a volumetric imbalance between the neurons and the vessels. We suggest that the observed structural correlation between neurons and blood vessels is related to neurovascular abnormalities in schizophrenia.

scholarly journals Coupled Fluid–Solid Numerical Simulation for Flow Field Characteristics and Supporting Performance of Flexible Support Cylindrical Gas Film Seal

Aerospace ◽  
2021 ◽  
Vol 8 (4) ◽  
pp. 97
Author(s):  
Junfeng Sun ◽  
Meihong Liu ◽  
Zhen Xu ◽  
Taohong Liao ◽  
Xiangping Hu ◽  
...  
Keyword(s):  
Flow Field ◽  
Film Thickness ◽  
Fluid Dynamic ◽  
Structural Characteristics ◽  
Structural Parameters ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
High Rotational Speed ◽  
Flexible Support ◽  
Flow Field Characteristics

A new type of cylindrical gas film seal (CGFS) with a flexible support is proposed according to the working characteristics of the fluid dynamic seal in high-rotational-speed fluid machinery, such as aero-engines and centrifuges. Compared with the CGFS without a flexible support, the CGFS with flexible support presents stronger radial floating characteristics since it absorbs vibration and reduces thermal deformation of the rotor system. Combined with the structural characteristics of a film seal, an analytical model of CGFS with a flexible wave foil is established. Based on the fluid-structure coupling analysis method, the three-dimensional flow field of a straight-groove CGFS model is simulated to study the effects of operating and structural parameters on the steady-state characteristics and the effects of gas film thickness, eccentricity, and the number of wave foils on the equivalent stress of the flexible support. Simulation results show that the film stiffness increases significantly when the depth of groove increases. When the gas film thickness increases, the average equivalent stress of the flexible support first decreases and then stabilizes. Furthermore, the number of wave foils affects the average foils thickness. Therefore, when selecting the number of wave foils, the support stiffness and buffer capacity should be considered simultaneously.

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