The Influence of Major Diameter Solid Particle on the Double-Channel Pump Performance

2011 ◽  
Author(s):  
Yi Li ◽  
Qiaoling Cui ◽  
Zuchao Zhu ◽  
Zhaohui He ◽  
Baoling Cui
Keyword(s):  
Numerical Simulation ◽  
Flow Rate ◽  
Sliding Wear ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Particle Diameter ◽  
Wall Region ◽  
Impeller Outlet ◽  
Anticlockwise Direction ◽  
Double Channel

Based on mixture model, the numerical simulation of solid-liquid two-phase flow in a double channel pump (Specific speed ns = 81) was carried out. The effects of particle diameter, particle volume fraction and flow rate on solid volume concentration distribution, relative velocity distribution and abrasion characteristics were studied. The results reveal that in the impeller, more particles concentrate at the nut of the shaft end and the edge of the impeller outlet. So those regions are worn seriously. The abrasive types are sliding wear on the impeller outlet edge and impact wear on the nut respectively. In the wall of the volute, the concentrated areas of particles move round the anticlockwise direction when the mixture flow rate is larger. The reason is the mixture velocity is larger as the flow rate increases, and meanwhile the centrifugal force and gravity force are invariable. So the particles move round the impeller rotational direction consequently. In the volute, particles concentrate on the tongue and wall region, especially on the sections I, II, V and VII. So the areas are easily worn out. The abrasive type is the heavy sliding wear in the volute wall. Numerical simulation results are consistent with the actual situation. It follows that the calculating method is feasible.

Vortex Simulation for Behavior of Solid Particles Falling in Air

2011 ◽  
Author(s):  
Hisanori Yagami ◽  
Tomomi Uchiyama
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Air Flow ◽  
Three Dimensional ◽  
Particle Diameter ◽  
Vortex Method ◽  
Solid Particles ◽  
Particle Volume ◽  
Two Phase ◽  
Spherical Region

The behavior of small solid particles falling in an unbounded air is simulated. The particles, initially arranged within a spherical region in a quiescent air, are made to fall, and their fall induces the air flow around them, resulting in the gas-particle two-phase flow. The particle diameter and density are 1 mm and 7.7 kg/m3 respectively. A three-dimensional vortex method proposed by one of the authors is applied. The simulation demonstrates that the particles are accelerated by the induced downward air flow just after the commencement of their fall. It also highlights that the particles are whirled up by a vortex ring produced around the downward air flow after the acceleration. The effect of the particle volume fraction at the commencement of the fall is also explored.

Effects of Particle Concentration on the Partitioning of Suspensions at Small Divergent Bifurcations

1996 ◽  
Vol 118 (3) ◽  
pp. 287-294 ◽  
Author(s):  
R. Ditchfield ◽  
W. L. Olbricht
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Particle Diameter ◽  
Circular Cross Section ◽  
Experimental Results ◽  
Hydrodynamic Interactions ◽  
Spherical Particles ◽  
Straight Tube ◽  
Particle Volume ◽  
Reynolds Number Flow

Experimental results are reported for the low Reynolds number flow of a suspension of spherical particles through a divergent capillary bifurcation consisting of a straight tube of circular cross-section that splits to form two tubes of equal diameter. The partitioning of particles between the downstream branches of the bifurcation is measured as a function of the partitioning of total volume (particles + suspending fluid) between the branches. Two bifurcation geometries are examined: a symmetric Y-shaped bifurcation and a nonsymmetric T-shaped bifurcation. This experiment focuses on the role of hydrodynamic interactions between particles on the partitioning of particles at the bifurcation. The particle diameter, made dimensionless with respect to the diameter of the branch tubes, ranges from 0.4 to 0.8. Results show that hydrodynamic interactions among the particles are significant at the bifurcation, even for conditions where interactions are unimportant in the straight branches away from the bifurcation. As a result of hydrodynamic interactions among particles at the bifurcation, the partitioning of particles between the branches is affected for particle volume fractions as small as 2 percent. The experimental results show that the effect of particle volume fraction is to diminish the inhomogeneity of particle partitioning at the bifurcation. However, the magnitude of this effect depends strongly on the overall shape of the bifurcation geometry, and, in particular on the angles between the branches.

An investigation on dry sliding wear behaviour of pressure infiltrated AA1050-XMg/B4C composites

2018 ◽  
Vol 25 (1) ◽  
pp. 67-73 ◽  
Author(s):  
Engin Cevik ◽  
Yavuz Sun ◽  
Yunus Turen ◽  
Hayrettin Ahlatci
Keyword(s):  
Weight Loss ◽  
Sliding Wear ◽  
Applied Load ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Wear Behaviour ◽  
Dry Sliding Wear ◽  
Dry Sliding ◽  
Pressure Infiltration ◽  
Sliding Wear Behaviour

AbstractIn this study, the effect of Mg alloying addition (1–4 wt.%) on dry sliding wear behaviour of AA1050 matrix composites was investigated. Composites were produced by the pressure infiltration technique at 800°C and had a B4C particle volume fraction of 60%. Reinforcement particles were uniformly distributed in the aluminium matrix. Compared with the AA1050 matrix, the weight loss of the composites decreased with increasing Mg content. The wear rate of the composites increased when the applied load and sliding distance were increased. The results show that when the applied load reaches critical values (30 N), the weight loss increases significantly.

Experimental Research on the Particles Reflux in the Particle Impact Drilling System

2011 ◽  
Vol 361-363 ◽  
pp. 381-385
Author(s):  
Zhen Zhong Ma ◽  
Yang Zhang ◽  
Bin Bin Wang
Keyword(s):  
Flow Rate ◽  
Volume Fraction ◽  
Drilling Fluid ◽  
Particle Volume Fraction ◽  
Drill Pipe ◽  
Dimension Theory ◽  
Particle Impact ◽  
Fluid Viscosity ◽  
Annular Gap ◽  
Drilling Technology

Particle Impact Drilling technology (PID) is a new drilling technology, which is designed especially to solve the oil and gas exploration under hard terrane. In PID system, the steel particles were added in the drilling fluid to impact rock. The particles would be recycled and put to use again, thus it is of great significance to adjust proper drilling fluid flow rate for steel particle’s reflux. The flow rate of drilling fluids carrying particles is influenced by the fluid viscosity, the annular gap between drill pipe and wellbore, the particle volume fraction and particle size, etc. This paper mainly studied the influence of the annular gap and the flow rate, while the other factors keep constant. Both experimental method and dimension theory were employed in the research. Furthermore, empirical formula was proposed to describe the mechanism.

Direct Numerical Simulation of Particle-Laden Turbulent Flows in Two-Way Coupling Using Equilibrium Assumption

2006 ◽  
Author(s):  
Babak Shotorban ◽  
S. Balachandar
Keyword(s):  
Numerical Simulation ◽  
Direct Numerical Simulation ◽  
Turbulent Flows ◽  
Isotropic Turbulence ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Concentration Field ◽  
Fluid Phase ◽  
Trajectory Approach ◽  
Two Fluid

A two-fluid approach is proposed for direct numerical simulation of particle-laden turbulent flows in two-way coupling through equilibrium assumption that is valid for particles with sufficiently small time constants. Making this assumption, a Eulerian velocity field is calculated for the particle phase through a truncated series expansion in terms of the velocity and acceleration of the fluid phase and the gravity acceleration. The transport equation of the Eulerian concentration field of particles (particle volume fraction) is solved along with the fluid phase equations for which the effect of particles on the fluid phase is taken into account through source terms in the momentum equations. For the assessment purposes, particle-laden isotropic turbulence is simulated. The results obtained through this approach are compared against those obtained by a trajectory approach in which the particle equations are solved in the Lagrangian framework. It is shown that there is a good agreement between the results obtained by the proposed two-fluid model and the trajectory approach by comparing the mean turbulent kinetic energy and its dissipation rate of the fluid phase as well as their spectra.

Investigation of Multiphase Unsteady Flow in a Double-Channel Pump by CFD Simulation and PIV Measurement

2012 ◽  
Author(s):  
Binjuan Zhao ◽  
Shouqi Yuan ◽  
Zhongfu Huang ◽  
Duohua Hou
Keyword(s):  
Unsteady Flow ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Volume Fraction ◽  
Particle Diameter ◽  
Tetrahedral Mesh ◽  
Data Set ◽  
Pressure Surface ◽  
Piv Measurement ◽  
Double Channel

The multiphase unsteady flow fields in a double-channel pump have been investigated both numerically and experimentally for the design condition and also off-design conditions. Three-dimensional, unsteady Reynolds-averaged Navier–Stokes equations are solved on high-quality unstructured tetrahedral mesh with the shear stress transport turbulence model by using the CFD code Fluent 6.4. Furthermore, PIV measurements are successfully conducted in the impeller, in order to capture the complex flow with abundant measurement data and to validate the CFD results. The main conclusions include: 1) The velocity field changes according to the blade orientation. When the impeller channel is near to the outlet of volute, the velocity distribution is relatively regular than when the impeller channel is far from the outlet of volute. 2) At the tongue of the volute, the fluid discharged from the impeller mixes with the re-circulating fluid in the volute, which contributes a lot to the impeller-volute interaction. 3) The pressure vibration in the volute is very obvious, pressure fluctuation on monitors far from the volute outlet is more obvious than those near to the volute outlet, and becomes stronger as drawing near the tongue. 4) The sand volume fraction distribution is extremely inhomogeneous in both impeller and volute. Particles mainly flow along the pressure surface and hub of the impeller; Particles mainly accumulate in the region near to the exit of volute, and the largest sand volume fraction is observed at the tongue. 5) Particle diameter has great influence on the particle distribution, and particles tend to accumulate on the pressure surface of the balde with the increase of particle diameter. 6) The total pressure difference of the pump declines with the increase of inlet sandy volume fraction or particle diameter. 7) PIV measurement results correspond well with the CFD simulation results, which in turn gives a good validation of the simulation accuracy. This work offers a good data set to develop the comprehension of the unsteady multiphase flow in the double-channel pump.

Numerical Simulation of Particle-Gas Flow Through a Fixed Pipe, Using One-Way and Two-Way Coupling Methods

2016 ◽  
Vol 33 (2) ◽  
pp. 205-212 ◽  
Author(s):  
Z. Namazian ◽  
A. F. Najafi ◽  
S. M. Mousavian
Keyword(s):  
Numerical Simulation ◽  
Gas Flow ◽  
Volume Fraction ◽  
Fluid Velocity ◽  
Particle Volume Fraction ◽  
Stokes Number ◽  
Continuous Phase ◽  
Turbulent Pipe Flow ◽  
Particle Volume ◽  
Two Phase

AbstractA numerical simulation of the particle-gas flow in a vertical turbulent pipe flow was conducted. The main objective of the present article is to investigate the effects of dispersed phase (particles) on continuous phase (gas). In so doing, two general forms of Eulerian-Lagrangian approaches namely, one-way (when the fluid flow is not affected by the presence of the particles) and two-way (when the particles exert a feedback force on the fluid) couplings were used to describe the equations of motion of the two-phase flow. Gas-phase velocities which are within the order of magnitude as that of particles, volume fraction, and particle Stokes number were calculated and the results were subsequently compared with the available experimental data. The simulated results show that when the particles are added, the fluid velocity is attenuated. With an increase in particle volume fraction, particle mass loading and Stokes number, velocity attenuation also increases. Moreover, the results indicate that an increase in particle Stokes number reduces the special limited particle volume fraction, according to which one-way coupling method yields plausible results. The results have also indicated that the significance of particle fluid interaction is not merely a function of volume fraction and particle Stokes number.

scholarly journals Dynamic characteristic analysis of vertical screw conveyor in variable screw section condition

2020 ◽  
Vol 103 (3) ◽  
pp. 003685042095105
Author(s):  
Jianming Yuan ◽  
Mingzhi Li ◽  
Fangping Ye ◽  
Zhenhui Zhou
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Screw Conveyor ◽  
Characteristic Analysis ◽  
Particle Volume ◽  
Flow Rate Increase ◽  
Particle Feeding

Vertical screw conveyors are used widely in industry for elevating bulk materials over relatively short distances, but the problem of insufficient feeding and low conveying efficiency always exist in the vertical conveying process. In this paper, a vertical screw conveyor with variable screw section is presented, and the characteristics of vertical screw conveyor are investigated under the variable screw sections using discrete element method (DEM). The results show that the particle volume fraction in the inlet and the mass flow rate increase in the condition of variable screw section, and the screw rotational speed has a significant influence on mass flow rate. It is evident that the design of variable screw section provides an effective way in improving the particle feeding rate and the conveying efficiency.

Design and Simulation of Continuous Dielectrophoretic Flow Sorters

2006 ◽  
Vol 22 (2) ◽  
pp. 99-106 ◽  
Author(s):  
T.-S. Leu ◽  
H.-Y. Chen ◽  
F-B. Hsiao
Keyword(s):  
Numerical Simulation ◽  
Linear System ◽  
Flow Rate ◽  
Applied Voltage ◽  
Particle Diameter ◽  
Length Ratio ◽  
Time Duration ◽  
Negative Particle ◽  
Electrical Fields ◽  
Inverse Proportion

AbstractThis paper was an attempt to investigate, through numerical simulation, the designs of DEP flow sorters when applied with different ratios of the electrodes to generate different electrical fields, and to explore the sorting capability of the flow sorters, defined as the degree of particle deflection, under different operation of parameters.In order to obtain the maximal DEP negative particle deflection, which was believed as an indicator of greater sorting capability, we have investigated different non-uniform electrical fields produced by combinations of electrodes with different length of two poles, ranging from 1:2 up to 1:9. The finding of numerical simulation indicated that the length ratio 1:3 of the electrode poles produced the electrical fields that maximized the particle deflection.Moreover, different parameters of applied voltage, flow rate, particle diameters, and distance between two electrical poles were designed to investigate their effects on particle deflection of flow sorters. The numerical simulation of the study showed that the DEP flow sorter was demonstrated as a linear system with respect to the applied voltage and particle diameter. In this study, we tried to operationally define flow rate as the time duration while the flow passed the electrical fields, and thus investigated how particle deflect with the different time given. We found that the particle deflected more when the flow was allowed with longer time to pass the electrical fields. The study also showed that the distance the particles deflect from the centerline is in inverse proportion to the square distance between the two electrical poles.

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