Computation and Experimental Results of Wear in a Slurry Pump Impeller

1986 ◽  
Vol 200 (6) ◽  
pp. 439-445 ◽  
Author(s):  
K Ahmad ◽  
R C Baker ◽  
A Goulas
Keyword(s):  
Computer Program ◽  
Calculation Method ◽  
Prediction Method ◽  
Internal Flow ◽  
Leading Edge ◽  
Solid Particles ◽  
Experimental Results ◽  
Pressure Side ◽  
Pump Impeller ◽  
Good Agreement

Using a computer program to obtain the internal flow in a pump impeller, the trajectories of solid particles were found and used to predict the regions of wear within the pump. In order to assess the validity of this prediction method tests were undertaken to obtain the erosion-prone areas of the pump by observing the erosion of layers of paint on the pump impeller. There was good agreement but the level of erosion was underestimated by the predictions. The calculation method and the use of paint to obtain wear patterns were both promising methods. Maximum wear in this case was near the leading edge on the pressure side and on the back shroud in the eye of the impeller.

Internal Flow Analysis in a Two-Channel Pump Used for Salt Transportation

2018 ◽  
Author(s):  
Jiaqi Wang ◽  
Xianwu Luo ◽  
Wanming Li ◽  
Bin Ji
Keyword(s):  
Particle Concentration ◽  
Flow Analysis ◽  
Internal Flow ◽  
Leading Edge ◽  
Pressure Side ◽  
Operation Condition ◽  
Static State ◽  
Erosion Risk ◽  
Salt Particle ◽  
Blade Leading Edge

Two-channel pumps usually have very complicated flow field due to the special impeller geometry. The present paper treats the internal flow analysis based on numerical simulation so as to investigate the pumping performance and passage erosion for a two-channel centrifugal pump used for transporting salt particles. The static state flows are calculated by applying RANS method and k-omega SST turbulence model. The numerical results indicate that there are strong circulation flows near the impeller inlet and blade pressure side, and zones with high turbulent kinetic energy near impeller exit when the pump is operated under the designed flow rate i.e. Qd. Pressure decay is also found at the rear part of blade pressure side. At the operation condition of 1.3Qd, the internal flow becomes better. Further, the numerical analysis based on Eulerian-Lagrangian method shows the trajectory of salt particle, salt particle concentration and erosion rate in the pump. It is noted that the salt particles go smoothly in the flow passage due to the large section size of the pump, and there is severe erosion at the blade leading edge and the wall of volute casing due to strong impingement and high particle concentration. Thus, these areas such as blade leading edge and the wall of volute casing are the zones with high erosion risk in the two-channel pump.

Numerical Simulation of Cavitating Flow in Mixed Flow Pump With Closed Type Impeller

2009 ◽  
Author(s):  
Katsutoshi Kobayashi ◽  
Yoshimasa Chiba
Keyword(s):  
Leading Edge ◽  
Suction Side ◽  
Experimental Results ◽  
Absolute Pressure ◽  
Pressure Side ◽  
Blade Surface ◽  
Mixed Flow ◽  
Closed Type ◽  
The Absolute ◽  
Flow Pump

LES (Large Eddy Simulation) with a cavitation model was performed to calculate an unsteady flow for a mixed flow pump with a closed type impeller. First, the comparison between the numerical and experimental results was done to evaluate a computational accuracy. Second, the torque acting on the blade was calculated by simulation to investigate how the cavitation caused the fluctuation of torque. The absolute pressure around the leading edge on the suction side of blade surface had positive impulsive peaks in both the numerical and experimental results. The simulation showed that those peaks were caused by the cavitaion which contracted and vanished around the leading edge. The absolute pressure was predicted by simulation with −10% error. The absolute pressure around the trailing edge on the suction side of blade surface had no impulsive peaks in both the numerical and experimental results, because the absolute pressure was 100 times higher than the saturated vapor pressure. The simulation results showed that the cavitation was generated around the throat, then contracted and finally vanished. The simulated pump had five throats and cavitation behaviors such as contraction and vanishing around five throats were different from each other. For instance, the cavitations around those five throats were not vanished at the same time. When the cavitation was contracted and finally vanished, the absolute pressure on the blade surface was increased. When the cavitation was contracted around the throat located on the pressure side of blade surface, the pressure became high on the pressure side of blade surface. It caused the 1.4 times higher impulsive peak in the torque than the averaged value. On the other hand, when the cavitation was contracted around the throat located on the suction side of blade surface, the pressure became high on the suction side of blade surface. It caused the 0.4 times lower impulsive peak in the torque than the averaged value. The cavitation around the throat caused the large fluctuation in torque acting on the blade.

The Influence of Oil Lubricated Journal Bearings on the Dynamics of Rotating Systems

1976 ◽  
Vol 190 (1) ◽  
pp. 627-633 ◽  
Author(s):  
H. McCallion ◽  
D. R. Wales
Keyword(s):  
Boundary Conditions ◽  
Computer Program ◽  
Translational Motion ◽  
Journal Bearings ◽  
Experimental Results ◽  
Oil Film ◽  
Rotating Systems ◽  
Film Boundary ◽  
Good Agreement

SYNOPSIS A computer program representing a shaft and rotor whirling in bearings which allows for realistic oil film boundary conditions and non-circular bearing profiles has been developed. It gave good agreement with experimental results published by Brown and France. With the aim of increasing understanding of the influence of bearing profile on system instability, the program calculates the timewise variation of the energy in translational motion supplied to the rotor by oil film forces. One case is illustrated.

The Steady State Rheological Behavior of Semisolid AlSi6Mg2 Alloy

2011 ◽  
Vol 339 ◽  
pp. 257-260 ◽  
Author(s):  
Hong Chao Luo ◽  
Shi Pu Chen ◽  
Qin Nie ◽  
En Sheng Xu ◽  
Li Ping Ju
Keyword(s):  
Steady State ◽  
Shear Rate ◽  
Rheological Behavior ◽  
Volume Fraction ◽  
Solid Volume Fraction ◽  
Solid Particles ◽  
Experimental Results ◽  
Present System ◽  
Flow Conditions ◽  
Good Agreement

In the present work, basing on the rheological model of Chen and Fan (CF) [1] of semisolid metal slurries (SSMS), the rheological behavior at steady state of AlSi6Mg2 alloy is investigated. Experimental results on steady state viscosity of the present system in the literature are used to determine the parameters of the CF model by fitting. It has been shown that the steady state viscosity and the average agglomerate size increase with increasing the solid volume fraction and decreasing the shear rate. The theoretical prediction of the CF model is in good agreement with the experimental results in the literatures quantitatively. The importance of the effective solid volume fraction is shown by explaining the strong coupling between the viscosity and the microstructure. Specifically, the external flow conditions such as shear rate influences the viscosity by changing the agglomeration degree of the solid particles, that is, the effective solid volume fraction and then changing the viscosity.

scholarly journals The Effect of Inlet Air Vitiation on Combustion Efficiency

1985 ◽  
Author(s):  
Fan Zuomin ◽  
Jiang Yijun
Keyword(s):  
Test Data ◽  
Calculation Method ◽  
Combustion Efficiency ◽  
Empirical Correlation ◽  
Experimental Results ◽  
Ramjet Combustor ◽  
Stirred Reactor ◽  
Good Agreement

Experimental results of the effect of inlet air vitiation produced by a vitiating preheater on combustion efficiency of a turbojet combustor and a model ramjet combustor are presented in this paper. An empirical correlation and a calculation method based on stirred reactor theory are derived to correct the vitiation effect. Results obtained by means of these two methods are in good agreement with test data.

scholarly journals Mathematical model of unsteady gas to solid particles heat transfer in fluidized bed

2009 ◽  
Vol 13 (1) ◽  
pp. 55-68 ◽  
Author(s):  
Mladen Stojiljkovic ◽  
Branislav Stojanovic ◽  
Jelena Janevski ◽  
Gradimir Ilic
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Computer Program ◽  
Fluidized Bed ◽  
Particle Temperature ◽  
Prediction Method ◽  
Solid Particles ◽  
Gas Temperature ◽  
One Dimensional ◽  
The Mathematical Model

The mathematical model of unsteady one-dimensional gas to particles heat transfer for non-isothermal fluidized bed with periodic heating of solid particles has been described. The method of numerical solution of governing differential equations, the algorithm and the computer program, have been presented. By using mathematical model and computer program, the temperature profiles for interstitial gas, gas in bubbles, and solid particles along the height of fluidized bed in function of time, have been determined. The results obtained on the basis of prediction method are compared to the experimental results of the authors; the satisfactory agreement has been found for interstitial gas temperature and solid particle temperature. On the basis of this comparison, the mathematical model has been verified.

Study of Heat Transfer and Hydrodynamics in a Gas-Solid Fluidized Bed Reactor Experimentally and Numerically

2011 ◽  
Vol 110-116 ◽  
pp. 4187-4197
Author(s):  
Mahdi Hamzehei ◽  
Hassan Rahimzadeh ◽  
Goodarz Ahmadi
Keyword(s):  
Heat Transfer ◽  
Computational Model ◽  
Fluidized Bed ◽  
Particle Temperature ◽  
Fluidized Bed Reactor ◽  
Solid Particles ◽  
Experimental Results ◽  
Heat Conducting ◽  
Momentum Exchange ◽  
Good Agreement

—In this research, the heat transfer and hydrodynamics of a gas–solid fluidized bed reactor were studied experimentally and computationally. A multi-fluid Eulerian computational model incorporating the kinetic theory for solid particles was developed and used to simulate the heat conducting gas–solid flows in a fluidized bed configuration. Momentum exchange coefficients were evaluated using the Syamlal–O’Brien drag functions. Temperature distributions of different phases in the reactor were also computed. Good agreement was found between the model predictions and the experimentally obtained data for the bed expansion ratio as well as the qualitative gas–solid flow patterns. The simulation and experimental results showed that the gas temperature decreases as it moves upward in the reactor, while the solid particle temperature increases. Pressure drop and temperature distribution predicted by the simulations were in good agreement with the experimental measurements at superficial gas velocities higher than the minimum fluidization velocity. Also, the predicted time-average local voidage profiles were in reasonable agreement with the experimental results. The study showed that the computational model was capable of predicting the heat transfer and the hydrodynamic behavior of gas-solid fluidized bed flows with reasonable accuracy.

scholarly journals Numerical Flow Simulation in a Centrifugal Pump at Design and Off-Design Conditions

2007 ◽  
Vol 2007 ◽  
pp. 1-8 ◽  
Author(s):  
K. W. Cheah ◽  
T. S. Lee ◽  
S. H. Winoto ◽  
Z. M. Zhao
Keyword(s):  
Centrifugal Pump ◽  
Three Dimensional ◽  
Flow Simulation ◽  
Internal Flow ◽  
Leading Edge ◽  
Design Flow ◽  
Vortical Flow ◽  
Navier Stokes ◽  
Pump Impeller ◽  
Rate Condition

The current investigation is aimed to simulate the complex internal flow in a centrifugal pump impeller with six twisted blades by using a three-dimensional Navier-Stokes code with a standardk-εtwo-equation turbulence model. Different flow rates were specified at inlet boundary to predict the characteristics of the pump. A detailed analysis of the results at design load,Qdesign, and off-design conditions, Q = 0.43Qdesignand Q = 1.45Qdesign, is presented. From the numerical simulation, it shows that the impeller passage flow at design point is quite smooth and follows the curvature of the blade. However, flow separation is observed at the leading edge due to nontangential inflow condition. The flow pattern changed significantly inside the volute as well, with double vortical flow structures formed at cutwater and slowly evolved into a single vortical structure at the volute diffuser. For the pressure distribution, the pressure increases gradually along streamwise direction in the impeller passages. When the centrifugal pump is operating under off-design flow rate condition, unsteady flow developed in the impeller passage and the volute casing.

Desiccant Dehumidification System for Space Radiant Cooling in Tropical Climate

2012 ◽  
Vol 622-623 ◽  
pp. 1575-1579
Author(s):  
T. Kiewkem ◽  
P. Chaiwiwatworakul ◽  
S. Chirarattananon
Keyword(s):  
Computer Program ◽  
Thermal Comfort ◽  
Simulation Study ◽  
Cooling System ◽  
Tropical Climate ◽  
Experimental Results ◽  
Radiant Cooling ◽  
Simulation Results ◽  
Good Agreement

This paper presents an experimental and simulation study on application of a rotating desiccant dehumidification system under a tropical climate. The system was used to dehumidify the ventilation air before supplying to a space where a radiant cooling system was installed to provide thermal comfort. In the study, a computer program of the desiccant system was coded and used to evaluate the system performances. The experimental results show good agreement with the results from coded program. Using the program, the simulation results demonstrate that the desiccant system can reduce and handle the load of the ventilation air. The results also show that in order to remove the whole latent load, the minimum regeneration temperature is 80°C.

CFD Evaluation of Internal Flow Effects on Turbine Blade Leading-Edge Film Cooling With Shaped Hole Geometries

2021 ◽  
Author(s):  
Christopher C. Easterby ◽  
Jacob D. Moore ◽  
David G. Bogard
Keyword(s):  
Film Cooling ◽  
Fluid Dynamic ◽  
Turbine Blades ◽  
Internal Flow ◽  
Leading Edge ◽  
Flow Fields ◽  
Experimental Results ◽  
Key Factor ◽  
Flow Effects ◽  
Film Cooling Holes

Abstract In gas turbine engines, the highest heat loads occur at the leading-edge areas of turbine blades and vanes. To protect the blades and vanes, a “showerhead” configuration of film cooling holes is often used for this location, in which several rows of holes are configured closely together to maximize film coverage. Typically, these film cooling holes are fed by impingement cooling jets, helping to cool the leading edge internally, but also changing the internal flow field. The effects of these internal flow fields on film cooling are not well known, and experimental research is very limited in its ability to analyze them. Because of this, computational fluid dynamic (CFD) simulations using RANS were used as a way to analyze these internal flow fields. To isolate the effects of the impingement jet, results were compared to a pseudo-plenum internal feed, and rotation in the hole was found to be a key factor in performance. Computational results from both coolant feed configurations were compared to experimental results for the same configurations. The CFD RANS results were found to follow the same trends as the experimental results for both the impingement-fed and plenum-fed cases, suggesting that RANS is able to accurately model some of the important physics associated with leading-edge film cooling.

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