scholarly journals Numerical Investigation of the Characteristics of Erosion in a Centrifugal Pump for Transporting Dilute Particle-Laden Flows

2021 ◽  
Vol 9 (9) ◽  
pp. 961
Author(s):  
Rui-Jie Zhao ◽  
You-Long Zhao ◽  
De-Sheng Zhang ◽  
Yan Li ◽  
Lin-Lin Geng
Keyword(s):  
Centrifugal Pump ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Finite Size ◽  
Wall Region ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Particle Volume ◽  
Impeller Blade ◽  
The Impact

Erosion in centrifugal pumps for transporting flows with dilute particles is a main pump failure problem in many engineering processes. A numerical model combining the computational fluid dynamics (CFD) and Discrete Element Method (DEM) is applied to simulate erosion in a centrifugal pump. Different models of the liquid-solid inter-phase forces are implemented, and the particle-turbulence interaction is also defined. The inertial particles considered in this work are monodisperse and have finite size. The numerical results are validated by comparing the results with a series of experimental data. Then, the effects of particle volume fraction, size, and shape on the pump erosion are estimated in the simulations. The results demonstrate that severe erosive areas are located near the inlet and outlet of the pressure side of the impeller blade, the middle region of the blade, the corners of the shroud and hub of the impeller adjoining to the pressure side of the blade, and the volute near the pump tongue. Among these locations, the maximum erosion occurs near the inlet of the pressure side of the blade. Erosion mitigation occurs under the situation where more particles accumulate in the near-wall region of the eroded surface, forming a buffering layer. The relationship between the particle size and the erosion is nonlinear, and the 1 mm particle causes the maximum pump erosion. The sharp particles cause more severe erosion in the pump because both the frequency of particle-wall collisions and the impact angle increase with the increasing sharpness of the particle.

scholarly journals Study on Wear Properties of the Flow Parts in a Centrifugal Pump Based on EDEM–Fluent Coupling

Processes ◽  
2019 ◽  
Vol 7 (7) ◽  
pp. 431
Author(s):  
Si Huang ◽  
Jiaxing Huang ◽  
Jiawei Guo ◽  
Yushi Mo
Keyword(s):  
Centrifugal Pump ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Leading Edge ◽  
Suction Side ◽  
Pressure Side ◽  
Flow Conditions ◽  
Wear Properties ◽  
Impeller Blade ◽  
Fluid Medium

By using EDEM–Fluent codes and coupling the continuous fluid medium with a solid particle discrete element, the solid–liquid two-phase flow field in a centrifugal pump was simulated under the same inlet conditions of the particle volume fraction and three flow conditions of 0.7Qd, 1.0Qd and 1.3Qd. By introducing the Archard wear model, the wear was calculated, and the wear law was obtained for the pump flow parts such as the leading edge of the impeller blade, blade tip, blade pressure side, blade suction side, impeller shroud, hub and volute. The results demonstrate that the wear of volute is about 70% of the total wear of pump. The wear in the impeller mainly occurs in the blade leading edge, the junction of the hub and the trailing part of the blade pressure side, and the junction of the shroud and the rear part of the blade suction side. Under lower flow conditions, the wear in the impeller shroud is relatively considerable. As the flow rate increases, the wear in the blade pressure side and the hub increases significantly.

scholarly journals Pressure Fluctuation Reduction of a Centrifugal Pump by Blade Trailing Edge Modification

Processes ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1408 ◽  
Author(s):  
Bin Huang ◽  
Guitao Zeng ◽  
Bo Qian ◽  
Peng Wu ◽  
Peili Shi ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Pressure Side ◽  
Centrifugal Pumps ◽  
Trailing Edge ◽  
Impeller Blade ◽  
Blade Passing Frequency ◽  
Impeller Outlet ◽  
Edge Profile ◽  
Edge Trimming

The pressure fluctuation inside centrifugal pumps is one of the main causes of hydro-induced vibration, especially at the blade-passing frequency and its harmonics. This paper investigates the feature of blade-passing frequency excitation in a low-specific-speed centrifugal pump in the perspective of local Euler head distribution based on CFD analysis. Meanwhile, the relation between local Euler head distribution and pressure fluctuation amplitude is observed and used to explain the mechanism of intensive pressure fluctuation. The impeller blade with ordinary trailing edge profile, which is the prototype impeller in this study, usually induces wake shedding near the impeller outlet, making the energy distribution less uniform. Because of this, the method of reducing pressure fluctuation by means of improving Euler head distribution uniformity by modifying the impeller blade trailing edge profile is proposed. The impeller blade trailing edges are trimmed in different scales, which are marked as model A, B, and C. As a result of trailing edge trimming, the impeller outlet angles at the pressure side of the prototype of model A, B, and C are 21, 18, 15, and 12 degrees, respectively. The differences in Euler head distribution and pressure fluctuation between the model impellers at nominal flow rate are investigated and analyzed. Experimental verification is also conducted to validate the CFD results. The results show that the blade trailing edge profiling on the pressure side can help reduce pressure fluctuation. The uniformity of Euler head circumferential distribution, which is directly related to the intensity of pressure fluctuation, is improved because the impeller blade outlet angle on the pressure side decreases and thus the velocity components are adjusted when the blade trailing edge profile is modified. The results of the investigation demonstrate that blade trailing edge profiling can be used in the vibration reduction of low specific impellers and in the engineering design of centrifugal pumps.

Radiation and non-uniform heat sink/source effects on 2D MHD flow of CNTs-H2O nanofluid over a flat porous plate

2019 ◽  
Vol 16 (4) ◽  
pp. 791-809
Author(s):  
Himanshu Upreti ◽  
Sawan Kumar Rawat ◽  
Manoj Kumar
Keyword(s):  
Magnetic Field ◽  
Heat Sink ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Porous Plate ◽  
Mhd Flow ◽  
Particle Volume ◽  
Content Type ◽  
Uniform Heat ◽  
The Impact

Purpose The purpose of this paper is to examine the velocity and temperature profile for a two-dimensional flow of single- and multi-walled nanotubes (CNTs)/H2O nanofluid over a flat porous plate, under the impact of non-uniform heat sink/source and radiation. The influence of suction/blowing, viscous dissipation and magnetic field is also incorporated. Design/methodology/approach The solution of the PDEs describing the flow of nanofluid is accomplished using Runge–Kutta–Fehlberg approach with shooting scheme. Findings Quantities of physical importance such as local Nusselt number and skin friction coefficient for both types of nanotubes are computed and shown in tables. Also, the impact of copious factors like Prandtl number, magnetic field, Eckert number, porosity parameter, radiation parameter, non-linear stretching parameter, injection/suction, heating variable, particle volume fraction and non-uniform heat sink/source parameter on temperature and velocity profile is explained in detail with the aid of graphs. Originality/value Till date, no study has been reported that examines the role of radiation and non-uniform heat sink/source on MHD flow of CNTs‒water nanofluid over a porous plate. The numerical outcomes attained for the existing work are original and their originality is authenticated by comparing them with earlier published work. This problem is of importance, as there are many applications of the fluid flowing over a flat porous plate.

Numerical study of heat transfer and Hall current impact on peristaltic propulsion of particle-fluid suspension with compliant wall properties

2019 ◽  
Vol 33 (35) ◽  
pp. 1950439 ◽  
Author(s):  
M. M. Bhatti ◽  
Rahmat Ellahi ◽  
A. Zeeshan ◽  
M. Marin ◽  
N. Ijaz
Keyword(s):  
Heat Transfer ◽  
Volume Fraction ◽  
Hall Current ◽  
Numerical Study ◽  
Nonlinear Differential Equations ◽  
Particle Volume Fraction ◽  
Mathematical Formulation ◽  
Solid Particles ◽  
Particle Volume ◽  
The Impact

In this paper, the effects of heat transfer and Hall current on the sinusoidal motion of solid particles through a planar channel has been discussed. The walls of the channel are considered as compliant under the effects of magnetohydrodynamics. The mathematical formulation has been performed using energy equation, momentum equation, and Ohm’s law. The modeled equations are further modified by taking the assumption of a zero Reynolds number and long wavelength. Numerical shooting technique has been employed to solve the nonlinear differential equations. The impact of all the emerging parameters such as wall rigidity, wall tension, mass characterization, Hall parameter, Hartmann number, Weissenberg number, particle volume fraction, Prandtl number, and Eckert number, respectively. Particularly, we discussed their effects on velocity and temperature profile.

Electro-osmosis modulated biologically inspired flow of solid liquid suspension in a channel with complex progressive wave: An application of targeted drugging

2021 ◽  
Author(s):  
A. Zeeshan ◽  
F. Bashir ◽  
F. Alzahrani
Keyword(s):  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Wave Length ◽  
Expansion Method ◽  
Body Parts ◽  
Particle Volume ◽  
Liquid Suspension ◽  
Electro Osmosis ◽  
Solid Liquid ◽  
The Impact

Electrokinetic microperistaltic pumps are important biomechanical devices, helps in targeted drugging of sick body parts. The current article is written to focus on mathematical modelling and analysis of some important aspect of such flows in a channel with complex wave. It is considered that solid partilcle are uniformly distributed in the flow and these particle are non-conducting. Parameters such as Particle volume fraction coefficient, Electro-osmotic parameter and Helmholtz-Smoluchowski parameter are specially been focused in this study. Spherical shaped equally sized are uniformly floated in a non-Newtonian Powell-Eyring base fluid. The defined flow problem is modelled and analyzed analytically for the transport of solid liquid suspension. It is accepted that the flow is steady, nonturbulent and propagating waves do have a considerably longer wave-length when compared to amplitude. The conditions and assumptions lead to a model of coupled partial differential equations of order two. The exact results by HPM expansion method are procured and shown accordingly. The predictions about the behaviour of important appearing parameters are displayed using figures. The impact of sundry parameters are analyzed. The application of current study involved transporting/ targeted drug delivery system using Peristaltic micropumps and magnetic field in pharmacological engineering of biofluids like blood.

scholarly journals Performance of Variable Negative Stiffness MRE Vibration Isolation System

2015 ◽  
Vol 2015 ◽  
pp. 1-8 ◽  
Author(s):  
Run-pu Li ◽  
Cheng-bin Du ◽  
Fei Guo ◽  
Guo-jun Yu ◽  
Xiao-guo Lin
Keyword(s):  
Magnetic Particles ◽  
Vibration Isolation ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Vibration Response ◽  
Negative Stiffness ◽  
Iron Core ◽  
Particle Volume ◽  
Isolation System ◽  
The Impact

Magnetorheological elastomer (MRE) vibration isolation devices can improve a system’s vibration response via adjustable stiffness and damping under different magnetic fields. Combined with negative stiffness design, these MRE devices can reduce a system’s stiffness and improve the vibration control effect significantly. This paper develops a variable negative stiffness MRE isolation device by combining an improved separable iron core with laminated MREs. The relationship between the negative stiffness and the performance of the device is obtained by mathematical transformation. Its vibration response under simple harmonic excitation at small amplitude and the impact of the volume fraction of soft magnetic particles on the isolation system are also analyzed. The results show that the negative stiffness produced by the magnetic force is a major factor affecting the capacity of the isolation system. Compared to devices of the same size, the isolation system equipped with low-particle volume fraction MREs demonstrates better performance.

scholarly journals Turbulent flow of finite-size spherical particles in channels with viscous hyper-elastic walls

2019 ◽  
Vol 873 ◽  
pp. 410-440 ◽  
Author(s):  
M. N. Ardekani ◽  
M. E. Rosti ◽  
L. Brandt
Keyword(s):  
Single Phase ◽  
Volume Fraction ◽  
Particle Volume Fraction ◽  
Finite Size ◽  
Spherical Particles ◽  
Normal Velocity ◽  
Particle Volume ◽  
Hyper Elastic ◽  
Rigid Walls ◽  
Elastic Walls

We study single-phase and particle-laden turbulent channel flows bounded by two incompressible hyper-elastic walls with different deformability at bulk Reynolds number $5600$. The solid volume fraction of finite-size neutrally buoyant rigid spherical particles considered is $10\,\%$. The elastic walls are assumed to be of a neo-Hookean material. A fully Eulerian formulation is employed to model the elastic walls together with a direct-forcing immersed boundary method for the coupling between the fluid and the particles. The data show a significant drag increase and the enhancement of the turbulence activity with growing wall elasticity for both the single-phase and particle-laden flows when compared with the single-phase flow over rigid walls. Drag reduction and turbulence attenuation is obtained, on the other hand, with highly elastic walls when comparing the particle-laden flow with the single-phase flow for the same wall properties; the opposite effect, drag increase, is observed upon adding particles to the flow over less elastic walls. This is explained by investigating the near-wall turbulence, where the strong asymmetry in the magnitude of the wall-normal velocity fluctuations (favouring positive $v^{\prime }$), is found to push the particles towards the channel centre. The particle layer close to the wall contributes to turbulence production by increasing the wall-normal velocity fluctuations, so that in the absence of this layer, smaller wall deformations and in turn turbulence attenuation is observed. For a moderate wall elasticity, we increase the particle volume fraction up to $20\,\%$ and find that particle migration away from the wall is the cause of turbulence attenuation with respect to the flow over rigid walls. However, for this higher volume fractions, the particle induced stress compensates for the decreasing Reynolds shear stress, resulting in a higher overall drag for the case with elastic walls. The effect of the wall elasticity on the overall drag reduces significantly with increasing particle volume fraction.

Effect of the Rotating Speed of Centrifugal Machine on Microstructures and Properties of Recycled WCP/Fe-C Composites

2011 ◽  
Vol 704-705 ◽  
pp. 1000-1005
Author(s):  
Yan Pei Song ◽  
Yong Kai Li ◽  
Hui Gai Wang
Keyword(s):  
Volume Fraction ◽  
Centrifugal Casting ◽  
Particle Volume Fraction ◽  
Wear Behaviour ◽  
Particle Volume ◽  
Rotating Speed ◽  
Centrifugal Machine ◽  
The Dead ◽  
Recycled Composites ◽  
The Impact

The dead or scrap WCP/Fe-C composites parts were remelted via medium frequency induction furnace. Two recycled composites rings were made of the remelted mixture by centrifugal casting method at 720rpm and 920rpm, respectively. The effect of rotating speed of centrifugal machine on microstructures and properties of the recycled composites rings were investigated by mechanical property tester, SEM, EDS, and XRD. The results show that the recycled rings are a composite structure consisting of outer recycled composites region reinforced with undissoved WCP and core Fe-C alloy region unreinforced. The undissoved WCP-distribution in the recycled composites region is even. At the rotating speed of 720 rpm, the particle volume fraction in the recycled composites region reaches 54 vol.%, the hardness and impact toughness attain to HRC55.8 and 3.5J/cm2, respectively. As the rotating speed is raised to 920 rpm, the particle volume fraction rises to about 70 vol.%, the hardness increases to HRC63.3 and yet the impact reduces to 2.8 J/cm2. The microstructure in the inner Fe-C alloy region consists of bainitic, precipitated carbides with short rod like shape and graphite phase. Finally, the high-speed sliding wear behaviour of the recycled composites rings was investigated in the paper. Keywords: The dead or scrap composites parts; Recycled composites; rotating speed of centrifugal machine; Microstructures and properties.

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