Numerical Simulation and Test Research on the Wear of Back Blades in Slurry Pumps

2016 ◽  
Author(s):  
Yi Tao ◽  
Shouqi Yuan ◽  
Jianrui Liu ◽  
Fan Zhang ◽  
Jianping Tao
Keyword(s):  
Optimization Design ◽  
Volume Fraction ◽  
Solid Phase ◽  
Wear Test ◽  
Solid Particles ◽  
Particle Model ◽  
Optimized Design ◽  
Trailing Edge ◽  
Blade Number ◽  
The Impact

Back blades are usually assembled on the outside surface of impeller back shroud as a sealing device in centrifugal slurry pumps. The presence of solid particles in slurry leads to an obvious problem about the abrasion of the flow components of pump. Especially, the life of sealing devices, like the back blades, the oil seals and the shaft sleeve, is only a quarter or less of other components. Hence, an important engineering significance lies in the research on the abrasion of back blades. In this paper, a single-stage horizontal type centrifugal pump was chosen as the main study model. The 3D model of the entire flow field was meshed by hexahedral structured grids. Based on the Particle model, which is an Eulerian multiphase method, the internal two-phase flow in the centrifugal slurry pump was simulated by using ANSYS CFX software. Six optimized design cases with the variation of back blades were analyzed to study the influence of vane profile and blade number of back blades on the abrasion characteristic and sealing performance. The main conclusions obtained are as follows: the volume fraction of solid phase achieved by simulation is in good agreement with the test results; the effect of vane profile on the flow of particles in the passages and the pressure on the seal is small; the usage of less back blade number will lower the flow constraint of blades on the particles and increase the area of axial vortex in each single passage, which means that the impact velocity of particles towards the pressure side grows and the pressure on the seal increases significantly. Based on the simulation mentioned above, two better cases were selected and manufactured for trial. Then, a wear test rig was set up to study the wear pattern of impeller during the operation of pump. Through the comparison of these two impellers after the wear test, it is found that: the back blades with the back forward shape can effectively reduce the abrasion of back blades at the pressure sides near the trailing edge; thickening the trailing edge of back blades to increase the life of back blades is feasible in practical application. The optimization design of back blades was preliminarily achieved which could provide some reference for the optimization design of back blades in centrifugal slurry pumps.

Comparative Assessment of Turbulence Models for Prediction of Flow-Induced Corrosion Damages

2011 ◽  
Author(s):  
Kaushik Das ◽  
Debashis Basu ◽  
Todd Mintz
Keyword(s):  
Corrosion Rate ◽  
Cross Sections ◽  
Volume Fraction ◽  
Solid Phase ◽  
Turbulence Models ◽  
Reynolds Stress Model ◽  
Continuous Phase ◽  
Comparative Assessment ◽  
Solid Particles ◽  
Protective Film

The present study makes a comparative assessment of different turbulence models in simulating the flow-assisted corrosion (FAC) process for pipes with noncircular cross sections and bends, features regularly encountered in heat exchangers and other pipeline networks. The case study investigates material damage due to corrosion caused by dissolved oxygen (O2) in a stainless steel pipe carrying an aqueous solution. A discrete solid phase is also present in the solution, but the transport of the solid particles is not explicitly modeled. It is assumed that the volume fraction of the solid phase is low, so it does not affect the continuous phase. Traditional two-equation models are compared, such as isotropic eddy viscosity, standard k-ε and k-ω models, shear stress transport (SST) k-ω models, and the anisotropic Reynolds Stress Model (RSM). Computed axial and radial velocities, and turbulent kinetic energy profiles predicted by the turbulence models are compared with available experimental data. Results show that all the turbulence models provide comparable results, though the RSM model provided better predictions in certain locations. The convective and diffusive motion of dissolved O2 is calculated by solving the species transport equations. The study assumes that solid particle impingement on the pipe wall will completely remove the protective film formed by corrosion products. It is also assumed that the rate of corrosion is controlled by diffusion of O2 through the mass transfer boundary layer. Based on these assumptions, corrosion rate is calculated at the internal pipe walls. Results indicate that the predicted O2 corrosion rate along the walls varies for different turbulence models but show the same general trend and pattern.

scholarly journals Combined wear of slurry erosion, cavitation erosion, and corrosion on the simulated ship surface

2019 ◽  
Vol 11 (3) ◽  
pp. 168781401983445 ◽  
Author(s):  
Liang Liang ◽  
Youxia Pang ◽  
Yong Tang ◽  
Hao Zhang ◽  
Hui Liu ◽  
...  
Keyword(s):  
Cavitation Erosion ◽  
Strong Support ◽  
Wear Test ◽  
Solid Particles ◽  
Surface Material ◽  
Slurry Erosion ◽  
Wear Rates ◽  
Ductile Materials ◽  
Ship Hulls ◽  
The Impact

The surface material of marine ship hulls suffers degradation by slurry erosion because of the impact of sands or solid particles in seawater. When the ship’s moving speed increases, pressure is changed suddenly and cavitation erosion will occur. Therefore, in the ocean, the corrosion of the surface material of the ship hulls is a combined damage in a slurry erosion and cavitation erosion states. An experimental device, for the combined wear, capable of simulating the above working conditions is designed and manufactured. A combined wear test of various materials (Q235, DH32, and NM360 steels) is conducted. The results show that cutting furrows of the slurry erosion, pinholes of the cavitation erosion, holes of electrochemical corrosion, and their combined effect increase the material wear rates and areas. Ductile materials of high strength have less slurry and cavitation damage, and more corrosion damage. For ductile materials of low strength, slurry and cavitation wear play an important role. When the slurry impact speed is increased, the wear degree of materials is also increased. This experimental setup for the combined wear provides a strong support for the development of wear-resistant materials for ship hulls and the structural optimization of ship hulls.

Three-Dimensional Numerical Simulation of Convective Melting of Solid Particles in a Fluid

1999 ◽  
Author(s):  
Y. L. Hao ◽  
Y.-X. Tao
Keyword(s):  
Volume Fraction ◽  
Solid Phase ◽  
Rectangular Cross Section ◽  
Three Dimensional ◽  
Phase Changes ◽  
Solid Particles ◽  
Preliminary Calculation ◽  
Two Phase ◽  
Closed Set ◽  
Gravity Effects

Abstract A physical model of two-phase flow and heat-mass transfer with the phase changes based on the theory of interacting continua is proposed. All terms in the conservation equations are analyzed and the constitutive equations are presented. A closed set of governing equations describing the convective melting of solid particles in a fluid is obtained. The numerical method is developed for the solution of velocity, temperature, and volume fraction of solid phase for the three-dimensional melting in a rectangular cross-section channel. Preliminary calculation, including gravity effects, shows that the result is reasonable. This study provides a basis for the theoretical and experimental investigation of convective melting of solid particles in a fluid.

Buoyancy-Driven Convection from a Vertical Heated Plate Suspended Inside a Nanofluid-Filled Cooled Enclosure

2020 ◽  
Vol 9 (1) ◽  
pp. 56-65
Author(s):  
Massimo Corcione ◽  
Antonio Natale ◽  
Alessandro Quintino ◽  
Vincenzo Andrea Spena
Keyword(s):  
Volume Fraction ◽  
Solid Phase ◽  
Brownian Diffusion ◽  
Heated Plate ◽  
Nanoparticle Dispersion ◽  
Two Phase ◽  
Square Enclosure ◽  
Average Temperature ◽  
Buoyancy Driven Convection ◽  
The Impact

Buoyancy-driven convection from a heated vertical plate suspended inside a nanofluid-filled square enclosure cooled at the walls, is studied numerically using a two-phase model based on the double-diffusive approach. The study is conducted under the assumption that the Brownian diffusion and thermophoresis are the only slip mechanisms by which the solid phase can develop a significant relative velocity with respect to the liquid phase. The system of the governing equations of continuity, momentum and energy for the nanofluid, and continuity for the nanoparticles, is solved by a computational code which incorporates three empirical correlations for the evaluation of the effective thermal conductivity, the effective dynamic viscosity and the coefficient of thermophoretic diffusion, all based on a high number of literature experimental data. The SIMPLE-C algorithm is used to handle the pressure-velocity coupling. Numerical simulations are executed using alumina-water nanofluids for different values of the diameter and the average volume fraction of the suspended nanoparticles, the plate length and position, the cavity width, the average temperature of the nanofluid, and the temperature difference imposed between the plate and the boundary walls of the enclosure. It is found that the impact of the nanoparticle dispersion into the base liquid increases remarkably with increasing the average temperature, whereas, by contrast, the other controlling parameters have just moderate effects. Moreover, when the top and bottom walls of the enclosure are cooled, keeping the sidewalls adiabatic, a periodic flow is detected, whose main features will be discussed.

The nonlinear dynamics of solidification of a binary melt with a quasi-equilibrium mushy region

1990 ◽  
Vol 68 (9) ◽  
pp. 790-793 ◽  
Author(s):  
Yu. A. Buyevich ◽  
L. Y. Iskakova ◽  
V. V. Mansurov
Keyword(s):  
Mass Transfer ◽  
Heat And Mass Transfer ◽  
Volume Fraction ◽  
Solid Phase ◽  
Internal Heat ◽  
Solid Particles ◽  
Mushy Region ◽  
Parameter Method ◽  
Quasi Equilibrium ◽  
Phase Volume Fraction

A mushy region (a two-phase zone) between the solid and liquid phases occurs often in the process of solidification of a binary melt. An analysis of the structure of the mushy region, which includes the liquid, solid particles, and dendrites extending from the bulk solid surface, is suggested. The processes of heat and mass transfer in the mushy region are considered on the basis of the small parameter method. The analysis leads to equations governing unsteady heat and mass transfer with internal heat, and mass sources within the mushy region, and it includes the condition for the absence of supercooling (the condition for the zone quasi-equilibrium), convection being neglected. The temperature, concentration of solute, and solid phase volume fraction are found. On the basis of this solution a new model of the process is formulated. Within the scope of this model the mushy region is replaced by a liquid–solid interface with discontinuous boundary conditions.

Effect of Rolling-Remelting SIMA Process on Semi-Solid Microstructure of ZCuSn10 Alloy

2014 ◽  
Vol 217-218 ◽  
pp. 418-425 ◽  
Author(s):  
Jia Wang ◽  
De Hong Lu ◽  
Han Xiao ◽  
Rong Feng Zhou ◽  
Rong Zhou ◽  
...  
Keyword(s):  
Liquid Phase ◽  
Deformation Process ◽  
Volume Fraction ◽  
Solid Phase ◽  
Solid Particles ◽  
Deformation Degree ◽  
Fine Grain ◽  
Sima Process ◽  
Semi Solid ◽  
Sharp Corners

Semi-solid billet of ZCuSn10 (Wt%: 88.25Cu, 10.48Sn) alloy is prepared by strain induced melt activated (SIMA) method which including rolling and remelting process. Firstly, ZCuSn10 alloy is casted, and rolling samples are cut from ingot casting. Secondly, the rolling samples are two pass or four pass rolled after holding 15 minutes at 450°C, then samples with 10% and 20% pre-deformation degree are obtained. The remelting samples are cut from pre-deformed samples. Lastly, the remelting samples are reheated up to 850°C or 875°C, water quenching after holding for 15 minutes. Then semi-solid microstructure of ZCuSn10 alloy is prepared. The semi-solid microstructure of ZCuSn10 alloy is observed and compared with annealed microstructure and microstructure of ZCuSn10 alloy directly remelted after casting. The results indicate that semi-solid microstructure of ZCuSn10 alloy by rolling-remelting SIMA process is uniform and fine grain, and spheroidization level of solid particle is well. The optimum semi-solid microstructure is obtained when alloy with pre-deformation 20% is remelted at 875°C for 15 minutes, the average grain diameter is about 75.80μm, shape factor is 1.62, and volume fraction of liquid phase reaches about 17.28%. Pre-deformation process plays a crucial role in grain refinement and spheroidization during SIMA process for preparing the semi-solid ZCuSn10 alloy, as pre-deformation degree and remelting temperature increases, volume fraction of liquid phase increases, the solid particles in semi-solid microstructure are smaller and rounder. The main mechanism of SIMA process preparing semi-solid billet of ZCuSn10 alloy is that pre-deformation breaks dendrites and stores energy of deformation into alloy, and promotes dendrites fusing through remelting process. Meanwhile, liquid phase occupies sharp corners of solid particles by Sn element diffusing from liquid phase into α solid phase, so that fine and uniform and globular α solid particles are gained.

scholarly journals Impact of the Plate Diameter on the Value of the Pre-Compaction Stress in Soils With Varied Textural Group

2016 ◽  
Vol 20 (3) ◽  
pp. 5-14 ◽  
Author(s):  
Dariusz Błażejczak ◽  
Jan B. Dawidowski
Keyword(s):  
Solid Phase ◽  
Classical Method ◽  
Testing Machine ◽  
Liquid Limit ◽  
Solid Particles ◽  
Degree Of Saturation ◽  
Dry Density ◽  
Stress Curve ◽  
Compaction Stress ◽  
The Impact

AbstractThe objective of the paper was to verify the previously obtained results of research concerning the impact of the plate diameter on the measured value of the pre-compaction stress of silt (NG), in conditions of a wider range of soil types and their initial stage. The research was carried out on samples with a diameter of 100 mm and height of 30 mm produced from the soil material (M) or collected from the subsoil of the selected soils (AWN) with the granulation type of: silt loam, loam, light loam, sandy-clay soil. The following soils properties were determined: the granulation type, density of the solid phase, content of humus and calcium carbonate, reaction, plastic and liquid limit. The properties of samples were described with moisture, dry density of solid particles, porosity of aeration, degree of plasticity and degree of saturation. The samples were loaded with a testing machine with plates with varied diameters. The value of the pre-compaction stress of soil was measured with the method of searching the crossing point of tangents with the secondary stress curve and the original stresses curve (a classical method). It was found out that for samples M with the degree of saturation of 0.40-0.50, the pre-compaction stress does not significantly depend on the plate diameter. For samples M or AWN, with the degree of saturation of 0.64-0.82, the pre-compaction stress significantly depends on the diameter of the plate. A conclusion was formulated that in the research of NG with the method of uniaxial defonnations, the relation of the diameter of the plate (d) to the diameter of the cylinder (D) should be within 0.5 ≤ d/D ≤ 0.8.

scholarly journals Study of Heat Transfer with Nonlinear Thermal Radiation on Sinusoidal Motion of Magnetic Solid Particles in a Dusty Fluid

2016 ◽  
Vol 46 (3) ◽  
pp. 75-94 ◽  
Author(s):  
M. M. Bhatti ◽  
A. Zeeshan ◽  
R. Ellahi
Keyword(s):  
Heat Transfer ◽  
Thermal Radiation ◽  
Volume Fraction ◽  
Solid Particles ◽  
Jeffrey Fluid ◽  
Physical Parameters ◽  
Nonlinear Thermal Radiation ◽  
Sinusoidal Motion ◽  
Magnetic Solid ◽  
The Impact

Abstract In this article, heat transfer with nonlinear thermal radiation on sinusoidal motion of magnetic solid particles in a dust Jeffrey fluid has been studied. The effects of Magnetohydrodynamic (MHD) and hall current are also taken under consideration. The governing equation of motion and energy equation are modelled with help of Ohms law for fluid and dust phases. The solutions of the resulting ordinary coupled partial differential equations are solved analytically. The impact of all the physical parameters of interest such as Hartmann number, slip parameter, Hall parameter, radiation parameter, Prandtl number, Eckert number and particle volume fraction are demonstrated mathematically and graphically. Trapping mechanism is also discussed in detail by drawing contour lines. The present analysis affirms many interesting behaviours, which permit further study on solid particles motion with heat and mass transfer.

The Numerical Simulation and Performance Analysis of the Vortex Pump for Solid-Liquid Two Phase Medium

2014 ◽  
Vol 527 ◽  
pp. 88-92
Author(s):  
Peng Yun Song ◽  
Hong Li Wang ◽  
Peng Cheng He
Keyword(s):  
Numerical Simulation ◽  
Volume Fraction ◽  
Internal Flow ◽  
Solid Particles ◽  
Two Phase ◽  
Pump Head ◽  
Phase Medium ◽  
And Performance ◽  
Solid Liquid ◽  
The Impact

The numerical simulation of a 3-D model of the internal flow field for a Vortex slurry pump has been analyzed in this paper. The impact of different solids volume fraction on the distribution of solid particle was analyzed. The expression of the pump head and efficiency was derived by the energy equation. The results show that either on the long blades or on the short blades, the content of the solid particles increases with the increasing of the volume fraction. The results by the expression of the pump head and efficiency are compared with the results of the simulations. The conclusions show that the expression results are similar with the numerical simulation results, and the main factors of affecting the inner and outer characteristics are the solid particles.

scholarly journals Impact of Friction on the Uniaxial Soil Sample Compression Process

2017 ◽  
Vol 21 (2) ◽  
pp. 49-58 ◽  
Author(s):  
Dariusz Błażejczak ◽  
Rafał Nowowiejski ◽  
Jan B. Dawidowski
Keyword(s):  
Friction Force ◽  
Solid Phase ◽  
Solid Particles ◽  
Carbonate Content ◽  
Dry Density ◽  
Cylinder Wall ◽  
Friction Forces ◽  
Soil Material ◽  
Sample Height ◽  
The Impact

AbstractThe objective of the research was to determine the impact of the friction force between the cylinder wall and soil on the soil compaction resistance in relation to the sample height and diameter of the compaction plate. Samples with the diameter of (D) 100 mm and heights (H) of 30, 50 or 100 mm made of of soil material collected from subsoil of the selected plastic soils were used. The soil material wasidentified by the following properties: the granulation type, density of the solid phase, humus and calcium carbonate content, reaction, plastic and liquid limit. Properties of the samples were described with moisture, dry density of solid particles, porosity of aeration, plastic degree and saturation. The samples were loaded with plates of varied diameters (dA: 20; 30; 50; 70; 80; 90 and 98 mm) measuring at the same time forces on the main plate (FA) and the bottom one (FB) with the fixed diameter (dB=98 mm). The registered relationships between the forces FA and FB and plate sinkage (samples deformation) were used for determination of the impact of external friction forces (between the cylinder wall and soil) on the compression resistance of soils. It was found out that the participation of the friction force in relation to the height of samples and plate diameter varied from 0 to ca. 70%. It was proved that one may avoid the impact of the plate diameter dA on the measurement of force FA, when the relation dA/D, for samples with the heights of H30 and H50, is respectively within 0.5 ≤ dA/D < 0.8 and 0.5 ≤ dA/D < 0.7.

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