Contrast Study on the Radial Velocity of the Flow Field of the Hydrocyclones with Different Inlet Structures

2011 ◽  
Vol 339 ◽  
pp. 624-629
Author(s):  
Lian Cheng Ren ◽  
Zheng Liang ◽  
Jiang Meng ◽  
Lin Yang ◽  
Jia Lin Tian
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Axial Symmetry ◽  
Separation Efficiency ◽  
Great Influence ◽  
The Other ◽  
Contrast Study ◽  
The One ◽  
Tangential Inlet

On the base of numerical simulation and theoretical analysis, the flow field of a conventional single-tangential-inlet Hydrocyclone and a newly put forward axial-symmetry double-tangential-inlet hydrocyclone were contrasted. The study shows that the inlet structure of the Hydrocylone has a great influence on the radial velocity of the flow field in the hydrocyclone and that the radial velocity in the hydrocyclone with single-tangential-inlet is not symmetry about the axis of the hydrocyclone; and on the other hand the radial velocity in the hydrocyclone with axial-symmetry double-tangential-inlet is symmetry about the axis of the hydrocyclone. The magnitude of the radial velocity of the flow in the hydrocyclone with single-tangential-inlet is greater than that in the hydrocyclone with axial-symmetry double-tangential-inlet hydrocyclone, which means the hydrocyclone with axial-symmetry double-tangential-inlet has greater capability than the rival one with single-tangential inlet. The symmetry about the axis of the hydrocyclone of the radial velocity means the radial velocities in the place where the radio is the same are constant, which means the hydrocyclone has a great separation efficiency. The conclusion is that changing the conventional hydrocyclone into the one with axial-symmetry double-tangential-inlet structure can offer greater separation capability and efficiency.

scholarly journals Influence of Vortex Finder Structure on Separation Performance of Double-Overflow Three-Product Hydrocyclones

Separations ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 79
Author(s):  
Yuekan Zhang ◽  
Jiangbo Ge ◽  
Lanyue Jiang ◽  
Hui Wang ◽  
Junru Yang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Experimental Research ◽  
Separation Efficiency ◽  
Structural Parameters ◽  
Separation Performance ◽  
Insertion Depth ◽  
Flow Field Characteristics ◽  
Vortex Finder ◽  
Fine Classification

In view of the difficulty of traditional hydrocyclones to meet the requirements of fine classification, a double-overflow three-product (internal overflow, external overflow and underflow) hydrocyclone was designed in this study. Numerical simulation and experimental research methods were used to investigate the effects of double-overflow flow field characteristics and structural parameters (i.e., internal vortex finder diameter and insertion depth) on separation performance. The research results showed that the larger the diameter of the internal vortex finder, the greater the overflow yield and the larger the cut size. The finest internal overflow product can be obtained when the internal vortex finder is 30 mm longer than the external vortex finder. The separation efficiency is highest when the internal vortex finder is 30 mm shorter than the external vortex finder.

scholarly journals Slit Wall Effect on the Stability of Wavy Vortex Flow

2014 ◽  
Vol 6 ◽  
pp. 853069 ◽  
Author(s):  
Dong Liu ◽  
Ying-ze Wang ◽  
Hyoung-Bum Kim ◽  
Fang-neng Zhu ◽  
Chun-lin Wang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Flow Regime ◽  
Experimental Measurement ◽  
Vortex Flow ◽  
Wall Effect ◽  
Taylor Vortices ◽  
Simulation Results ◽  
The Stability

The wavy vortex flow in the plain model was studied by experimental measurement; the preliminary feature of wavy vortex flow was obtained. This flow field in the plain model was also studied by numerical simulation. The reliability of numerical simulation was verified by comparing with the experimental and numerical simulation results. To study the slit wall effect on the wavy vortex flow regime, another two models with different slit number were considered; the slit number was 6 and 12. By comparing the wavy vortex flow field in different models, the axial fluctuation of Taylor vortices was found to be different, which was increased with the increasing of slit number. The maximum radial velocity from the inner cylinder to the outer one in the 6-slit number was increased by 12.7% compared to that of plain model. From the results of different circumferential position in the same slit model, it can be found that the maximum radial velocity in slit plane is significantly greater than that in other planes. The size of Taylor vortices in different models was also calculated, which was found to be increased in the 6-slit model but was not changed as the slit number increased further.

Numerical Simulation of Cold Swirl Field for Solid Fuel Ramjet with NACA Airfoil

2014 ◽  
Vol 716-717 ◽  
pp. 711-716
Author(s):  
Jie Yu ◽  
Xiong Chen ◽  
Hong Wen Li
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Radial Velocity ◽  
Solid Fuel ◽  
Velocity Gradient ◽  
Pressure Loss ◽  
Total Pressure ◽  
Swirl Flow ◽  
Total Pressure Loss ◽  
Swirl Number

In order to study the swirl flow characteristics in the solid fuel ramjet chamber, a new type of annular vane swirler with NACA airfoil is designed. The cold swirl flow field in the chamber is numerically simulated with different camber and t attack angle, while the swirl number , swirl flow field structure, total pressure recovery coefficient were studied. According to numerical simulation result, the main factors in swirl number are camber and angle of attack, the greater angle of attack, the greater the camber ,the stronger swirl will be. Results show that the total pressure loss is mainly concentrated in the inlet section, the total pressure loss cause by vane swirler is small. Radial velocity gradient exists in swirling flow, and increases with the swirl number. With the influence of centrifugal force and combustion chamber structure, the radial velocity gradient increases.

Numerical Simulation on the Electrophoretic Motion of Multiple Particles in Microchannels

2004 ◽  
Author(s):  
Chunzhen Ye ◽  
Dongqing Li
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Electric Field ◽  
Particle Motion ◽  
Outer Region ◽  
Numerical Results ◽  
The Other ◽  
Double Layers ◽  
Rectangular Microchannel ◽  
Moving Particle

This paper considers the electrophoretic motion of multiple spheres in an aqueous electrolyte solution in a straight rectangular microchannel, where the size of the channel is close to that of the particles. This is a complicated 3-D transient process where the electric field, the flow field and the particle motion are coupled together. The objective is to numerically investigate how one particle influences the electric field and the flow field surrounding the other particle and the particle moving velocity. It is also aimed to investigate and demonstrate that the effects of particle size and electrokinetic properties on particle moving velocity. Under the assumption of thin electrical double layers, the electroosmotic flow velocity is used to describe the flow in the inner region. The model governing the electric field and the flow field in the outer region and the particle motion is developed. A direct numerical simulation method using the finite element method is adopted to solve the model. The numerical results show that the presence of one particle influences the electric field and the flow field adjacent to the other particle and the particle motion, and that this influences weaken when the separation distance becomes bigger. The particle motion is dependent on its size, with the smaller particle moving a little faster. In addition, the zeta potential of particle has an effective influence on the particle motion. For a faster particle moving from behind a slower one, numerical results show that the faster moving particle will climb and then pass the slower moving particle then two particles’ centers are not located on a line parallel to the electric field.

On the capture of interstellar matter by stars

1940 ◽  
Vol 36 (3) ◽  
pp. 314-322 ◽  
Author(s):  
R. d'E. Atkinson
Keyword(s):  
Radial Velocity ◽  
The Other ◽  
Interstellar Matter ◽  
Centre Of Gravity ◽  
Compelling Reason ◽  
Other Hand ◽  
The Mean ◽  
The One ◽  
The Individual ◽  
Capture Radius

The derivation given by Hoyle and Lyttleton for an accretion formula proposed by them is examined. A number of arguments against its validity are put forward, especially that on the one hand their capture radius depends on the theorem that if the velocity of certain masses of gas after collision is less than the velocity of escape at the point, they will not in fact escape, while on the other hand it is clear (and is now admitted) that the gas cannot in fact move with this velocity at all. It is also shown that since, ex hypothesi, the individual molecules will all, on the average, retain their hyperbolic velocities, there is not the compelling reason for their capture that there appeared to be in Hoyle and Lyttleton's argument, where only the mean radial velocity of the centre of gravity of the mass was considered. Further, it seems improbable that the temperature of the interstellar matter can be low enough for the initial assumptions of their theory to hold.

Constructing stage discharge relationship with numerical simulation including hydraulic resistance

2020 ◽  
Author(s):  
atsuhiro yorozuya
Keyword(s):  
Numerical Simulation ◽  
Risk Assessment ◽  
Shear Stress ◽  
Flow Field ◽  
Flow Resistance ◽  
River Flow ◽  
Flow Simulation ◽  
Flood Risk Assessment ◽  
The One ◽  
Flow Stage

<p>A flood risk assessment has implemented with an inundation map or with other simulated results; e.g., a rainfall-runoff simulation. In order to conduct the flood risk assessment, it is usual that the case with maximum floods are subject for discussion. At the same time, it is usual that observed data of the maximum floods are not available, since the maximum floods has not experienced, or observation have not conducted. Estimation of the discharge values are not simple, since the river flow at the targeted cross section are affected by river shape, or roughness changes. Both of them are sensitive with different flow stage.</p><p>The present study discusses about constructing the stage discharge relationship with numerical simulation. For this purpose, the author implements the 2-D depth integrated flow simulation including the flow resistance. The flow resistance is one of the traditional studies of the sediment hydraulics. It deals with the changing of resistance with different micro-scale bed forms as the bed shear stress changes. Similar with the one by Engelund (1966), the relationship with grain shear stress and total shear stress are constructed in qualitative manner by Kishi and Kuroki (1973). It is useful to obtain the bed roughness with different flow stage. The author implements the changes of the roughness in the 2-D depth integrated flow simulation and obtains the flow field in actual river flow in order to obtain the discharge values.</p><p>The authors conducted the numerical simulation in steady flow condition. In order to construct the stage-discharge relationship based on the results, 10 different cases with appropriate ranges of stage were conducted. The domain of the simulation is 5 times longer than the width of the targeted section. In order to construct the initial condition, bathymetry data in the one point in 5 m with the laser technique, and sediment size distribution at the different location; e.g., at center of flow, top of the dune and etc., were obtained. The calculated results were compared with observed flow field by float measurements and other non-contact current meter. The results indicate that the numerical stage-discharge relationship shows some good agreements and few disagreements with the one created based on observation. For example, at the water stage which represents the dune I, the simulated results are similar with observed. However, at the stage of dune II, simulated velocity shows smaller velocity than observed. As Hirai (2015) suggested, shape of micro-bed form classified as Dune II is unstably changes between Dune and flat bed. Therefore, velocity at the stage is sensitively changes as well. From this aspect, the authors concluded that not only the numerical simulation but also field measurement are necessary in order to construct good stage-discharge relationships, in particular if the shear stress at the targeted discharge involves the Dune II.</p>

scholarly journals AKAR-AKAR TRADISI POLITIK SUNNI DI INDONESIA

ALQALAM ◽  
2009 ◽  
Vol 26 (2) ◽  
pp. 171
Author(s):  
Muhammad Iqbal
Keyword(s):  
Great Influence ◽  
Colonial Period ◽  
The Other ◽  
The Political ◽  
Great Role ◽  
Other Hand ◽  
The Social ◽  
The Government ◽  
The One ◽  
Dutch Colonial

The Sunni doctrine plays an important role in the government. Its accommodative characteristic is something important that makes Sunni doctrine to be a device of the legitimation of the authority. The Muslim thinkers of classical Sunni such as al-Mawardi (975-1058 M), al-Ghazali (1058-1111 M) and lbn Taimiyah(1263-1329 M) have a great role in formulating the political doctrine of Sunni. In spite of the different nuance, all of these three classical Sunni thinkers develop the moderate political doctrine of Sunni. On the one hand, it is, of course, significant in situating the harmonious relation between the ruler and community. Therefore, the social and political stabilities will be well-maintained On the other hand, such a thought for a certain extent evokes stagnancy. Because there is no radical thought which is critical and opposite against the authority, the Sunni idea is frequently made use for the instantaneous interests of power. On evenlttally, the mutual interrelationship between the Sunni ulama and the ruler often happens. While ulama feel obtaining the patronage from the authority, the ruler gains religious justification from ulama. In this context, Indonesia as the country with the majority of Sunni Muslims, as a matter of fact, applies the political doctrine of Sunni. It is because Sunni has had a long and establishei root since. the period of Islamic kingdoms in the archipelago, before Dutch-Colonial period. The archipelago ulama also formulated the harmonious relation between Islam and authority as formulated by the ulama of classical Sunni. The polotical tradition of Sunni was becoming stronger in line with the great influence of ulama in the archipelago kingdoms. This article tries to elaborate the relation between the Sunni ulama with the power of the kings in the archipelago and the patronage of the archipelago rulers toward them.

scholarly journals Numerical Investigation of Flow Field and Energy Loss in a Centrifugal Pump as Turbine

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Jingze Li ◽  
Dongrong Meng ◽  
Xun Qiao
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Energy Loss ◽  
Entropy Generation ◽  
Flow Separation ◽  
Guide Vane ◽  
Great Influence ◽  
Internal Flow ◽  
Asymmetric Structure ◽  
Centrifugal Pumps

Centrifugal pumps as turbine (PAT) are widely used in petrochemical and water conservancy industries. The research on the internal flow field and energy loss of PAT is of great significance to improve the performance and efficiency of PAT. In this paper, experimental and numerical simulation methods are used to study the energy loss and flow field. The results show that the numerical simulation method can accurately simulate the internal flow field of PAT. And the entropy generation theory is applied to visualize the internal energy loss of PAT through the comparison of total pressure loss and entropy generation. The highest energy loss among PAT components is the guide vane. The loss in the guide vane is mainly caused by the flow separation caused by the wake of the guide vane and the asymmetric structure of the volute. The losses in the impeller are mainly due to flow separation and wake. Besides, the unsteady simulation results show that rotor-stator interaction has a great influence on the gap between the impeller and the guide vane. The research results provide a reference for the design of the PAT. This study is beneficial to studying the dynamic and static interference and PAT vibration to improve the stability of the PAT.

Research on Hover Characteristics of Ducted Fan with Coaxial Rotors

2013 ◽  
Vol 427-429 ◽  
pp. 216-220
Author(s):  
Xing Zhu He ◽  
Shu Nan Liu ◽  
Yan Li Chen ◽  
Chun Xue Wang ◽  
Song Yang
Keyword(s):  
Numerical Simulation ◽  
Flow Field ◽  
Aerodynamic Characteristics ◽  
Complex Flow ◽  
Ducted Fan ◽  
The One ◽  
Coaxial Rotors

The method of handling respectively is used to refine the grid of ducted fan with coaxial rotors. Research the complex flow field of the ducted fan by numerical simulation to analyze its hover characteristics. The curve of the upper rotors lift, the lower rotors lift, the ducts lift with collective and the distance between rotors is got respectively. By comparing with the aerodynamic characteristics of ducted fan with a single rotor, results show that there is interference between the upper and lower rotors, the upper one interferes the lower one more heavily and interference is reduced with the increase of distance between the rotors; the duct of ducted fan with coaxial rotors can provide more lift than the one with a single rotor.

QUANTUM NUMBER PROJECTIONS OF NUCLEAR DEFORMED STATES

2006 ◽  
Vol 15 (03) ◽  
pp. 643-657 ◽  
Author(s):  
M. R. OUDIH ◽  
M. FELLAH ◽  
N. H. ALLAL ◽  
N. BENHAMOUDA
Keyword(s):  
Angular Momentum ◽  
Quantum Number ◽  
General Expression ◽  
Projection Method ◽  
Axial Symmetry ◽  
Particle Number ◽  
The Other ◽  
Equilibrium Deformation ◽  
System Energy ◽  
The One

We combine the exact particle-number projection method with the method of Peierls-Yoccoz in order to build the simultaneous eigen-functions of the particle number and the angular momentum operators. In the axial symmetry case, the general expression of the system energy resulting from this double projection is derived. In order to overcome the complexity of the method, the calculations are performed within the Gaussian overlap approximation. It turns out that, on the one hand, the double projection introduces a non–negligible correction of the energy of the system, and on the other hand, this correction is sensitive to the deformation. Future calculations have to therefore include an evaluation of the equilibrium deformation.

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