scholarly journals Performance Optimization of Centrifugal Pump for Crude Oil Delivery

2018 ◽  
Vol 15 (1) ◽  
pp. 88 ◽  
Author(s):  
S.A.I. Bellary ◽  
Afzal Hussain ◽  
Abdus Samad ◽  
R.A. Kanai
Keyword(s):  
Crude Oil ◽  
Centrifugal Pump ◽  
Performance Optimization ◽  
Oil And Gas ◽  
Stokes Equations ◽  
Reverse Flow ◽  
Flow Characteristics ◽  
Vortical Flow ◽  
Centrifugal Pumps ◽  
Pump Performance

Crude oil transport is an essential task in oil and gas industries, where centrifugal pumps are extensively used. The design of a centrifugal pump involves a number of independent parameters which affect the pump performance. Altering some of the parameters within a realistic range improves pump performance and saves a significant amount of energy. The present research investigated the pump characteristics by modifying the number of blades and the exit blade-angles. Reynolds-Averaged Navier-Stokes equations with standard k-ε two-equation turbulence closure were used for steady and incompressible flow of crude oil through the pump. The experimental set-up was installed and the pump performance calculated numerically  was compared with the experiments.   The investigations showed that the number of blades and the exit blade-angles have a significant influence on the head, shaft power, and efficiency. The vortical flow structures, recirculation and reverse flow characteristics around the impeller were investigated to explain the flow dynamics of impeller and casing. A larger number of blades on the rotor showed dominant streamlined flow without any wake phenomena. The combined effect of the number of blades and exit blade angle has led to an increase in head and efficiency through the parametric optimization.

scholarly journals Investigation on centrifugal pump performance degradation under air-water inlet two-phase flow conditions

2018 ◽  
pp. 41-48 ◽  
Author(s):  
Qiaorui Si ◽  
Qianglei Cui ◽  
Keyu Zhang ◽  
Jianping Yuan ◽  
Gérard Bois
Keyword(s):  
Centrifugal Pump ◽  
Pressure Pulsation ◽  
Flow Characteristics ◽  
Performance Degradation ◽  
Inlet Pressure ◽  
Pulsation Frequency ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Flow Rates ◽  
Pump Performance

In order to study the flow characteristics of centrifugal pumps when transporting the gas-liquid mixture, water and air were chosen as the working medium. Both numerical simulation and experimental tests were conducted on a centrifugal pump under different conditions of inlet air volume fraction (IAVF). The calculation used URANS k-epsilon turbulence model combined with the Euler-Euler inhomogeneous two-phase model. The air distribution and velocity streamline inside the impeller were obtained to discuss the flow characteristics of the pump. The results show that air concentration is high at the inlet pressure side of the blade, where the vortex will exist, indicating that the gas concentration have a great relationship with the vortex aggregation in the impeller passages. In the experimental works, pump performances were measured at different IAVF and compared with numerical results. Contributions to the centrifugal pump performance degradations were analyzed under different air-water inlet flow condition such as IAVF, bubble size, inlet pressure. Results show that pump performance degradation is more pronounced for low flow rates compared to high flow rates. Finally, pressure pulsation and vibration experiments of the pump model under different IAVF were also conducted. Inlet and outlet transient pressure signals under four IAVF were investigated and pressure pulsation frequency of the monitors is near the blade passing frequency at different IAVF, and when IAVF increased, the lower frequency signal is more and more obvious. Vibration signals at five measuring points were also obtained under different IAVF for various flow rates.

Numerical simulation of the stalled flow within a vaned centrifugal pump

2004 ◽  
Vol 218 (4) ◽  
pp. 425-435 ◽  
Author(s):  
K M Guleren ◽  
A Pinarbasi
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
High Speed ◽  
Stokes Equations ◽  
Reverse Flow ◽  
Flow Characteristics ◽  
Navier Stokes ◽  
Leakage Flow ◽  
Navier Stokes Equations ◽  
Low Pass

The main goal of the present work is to analyse the numerical simulation of a centrifugal pump by solving Navier-Stokes equations, coupled with the ‘standard k-∊’ turbulence model. The pump consists of an impeller having five curved blades with nine diffuser vanes. The shaft rotates at 890r/min. Flow characteristics are assumed to be stalled in the appropriate region of flowrate levels of 1.31-2.861/s. Numerical analysis techniques are performed on a commercial FLUENT package program assuming steady, incompressible flow conditions with decreasing flowrate. Under stall conditions the flow in the diffuser passage alternates between outward jetting when the low-pass-filtered pressure is high to a reverse flow when the filtered pressure is low. Being below design conditions, there is a consistent high-speed leakage flow in the gap between the impeller and the diffuser from the exit side of the diffuser to the beginning of the volute. Separation of this leakage flow from the diffuser vane causes the onset of stall. As the flowrate decreases both the magnitude of the leakage within the vaneless part of the pump and reverse flow within a stalled diffuser passage increase. As this occurs, the stall-cell size extends from one to two diffuser passages. Comparisons are made with experimental data and show good agreement.

Effect of Baffles in Between Stages on Performance and Flow Characteristics of a Two-Stage Split Case Centrifugal Pump

2017 ◽  
Author(s):  
Yiyun Wang ◽  
Ji Pei ◽  
Shouqi Yuan ◽  
Wenjie Wang
Keyword(s):  
Centrifugal Pump ◽  
High Efficiency ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Production Method ◽  
Navier Stokes ◽  
Centrifugal Pumps ◽  
Two Stage

Two-stage split case centrifugal pumps play an important role in large flow rate and high lift water transfer situations. To investigate the influence of baffles in between stages on the performance and internal flow characteristics, the unsteady simulations for the prototype pump were carried out by solving the three-dimensional Reynolds-averaged Navier-Stokes equations with a shear stress transport (SST) turbulence model. The structured grids were generated for the whole flow passage. The calculated performance results were verified by the experimental measurements. The entropy production method based on numerical simulation was applied to analyze the distribution and mechanism of flow losses. The results show that the turbulence dissipation is the dominant flow loss, and the viscous dissipation can be neglected. The baffles can reduce the turbulence dissipation power obviously and can improve the hydraulic efficiency by maximum 5%, especially under QBEP and over-load conditions. The baffles have the greatest effect on the hydraulic losses in the double suction impeller., because they change the flow characteristics in the channels between the first stage impeller and the double suction impeller, affecting the inflow condition dramatically for the impeller. The study can give a reference to optimize the design of the two-stage split case centrifugal pump for high efficiency.

scholarly journals The Effect of Viscosity on Performance of a Low Specific Speed Centrifugal Pump

2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Rouhollah Torabi ◽  
Seyyed Ahmad Nourbakhsh
Keyword(s):  
Centrifugal Pump ◽  
Stokes Equations ◽  
Reduction Rate ◽  
Viscous Fluids ◽  
Navier Stokes ◽  
Centrifugal Pumps ◽  
Navier Stokes Equations ◽  
Pump Performance ◽  
Low Specific Speed ◽  
Specific Speed

Centrifugal pump delivery head and flow rate drop effectively during the pumping of viscous fluids. Several methods and correlations have been developed to predict reduction rate in centrifugal pump performance when handling viscous fluids, but their results are not in very good agreement with each other. In this study, a common industrial low specific speed pump, which is extensively used in different applications, is studied. The entire pump, including impeller, volute, pipes, front and rear sidewall gaps, and balance holes, is simulated in Computational Fluid Dynamics and 3D full Navier Stokes equations are solved. CFD results are compared with experimental data such as pump performance curves, static pressure in casing, and disk friction loss. Dimensionless angular velocity and leakage rate are investigated in sidewall gap and efficiency variation due to viscosity is studied. The results demonstrate that the behavior of the fluid in sidewall gap is strictly sensitive to viscosity. Increasing viscosity improves the volumetric efficiency by reducing internal leakage through wear rings and balance holes, causing, however, a significant fall in the disk and overall efficiency. Results lead to some recommendations for designing centrifugal pumps which may be used in transferring viscous fluids.

Performance and Internal Flow Characteristics of a Very Low Specific Speed Centrifugal Pump

2005 ◽  
Vol 128 (2) ◽  
pp. 341-349 ◽  
Author(s):  
Young-Do Choi ◽  
Junichi Kurokawa ◽  
Jun Matsui
Keyword(s):  
Centrifugal Pump ◽  
Reverse Flow ◽  
Tangential Velocity ◽  
Flow Characteristics ◽  
Internal Flow ◽  
Centrifugal Pumps ◽  
Positive Displacement ◽  
Speed Range ◽  
Low Specific Speed ◽  
Specific Speed

In very low specific speed range (ns<0.25), the efficiency of the centrifugal pump designed by the conventional method becomes remarkably low. Therefore, positive-displacement pumps have been widely used for long. However, the positive-displacement pumps remain associated with problems such as noise and vibration and they require high manufacturing precision. Since the recently used centrifugal pumps are becoming higher in rotational speed and smaller in size, there appear to be many expectations to develop a new centrifugal pump with high performance in the very low specific speed range. The purpose of this study is to investigate the internal flow characteristics and its influence on the performance of a very low specific speed centrifugal pump. The results show that large reverse flow at the semi-open impeller outlet decreases absolute tangential velocity considerably which in turn decreases the pumping head.

Study on the Reduction of Pressure Fluctuation for a Double-Suction Centrifugal Pump With Staggered Blades

2018 ◽  
Author(s):  
Qian-qian Li ◽  
Da-zhuan Wu
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
Cfd Simulation ◽  
Stokes Equations ◽  
Low Noise ◽  
Living Environment ◽  
Centrifugal Impeller ◽  
Fluctuation Analysis ◽  
Centrifugal Pumps ◽  
Vibration Performance

Due to the distinctive characteristic of massive flow rates, double-suction centrifugal pump has been extensively applied in lots of perspectives, such as drainage, irrigation, transportation projects and other hydraulic engineering realms. Nevertheless, the significance of the pressure fluctuation inside the double-suction centrifugal pump, which is getting more and more prominent under the soaring demands for low noise and comfortable living environment, could not be underestimated. Consequently, how to reduce the pressure fluctuation as far as possible and enhance the running stability of the pump is always the research hotspot. In this study, the double-suction centrifugal impeller with abominable vibration performance is redesigned to improve the internal flow and reduce the flow-induced noise. What’s addition, the two redesigned impellers wearing splitter blades were compared in staggered arrangement with different angles for the purpose of ulteriorly decreasing the pressure fluctuation. On the basis of Realizable k-ε model and SIMPLEC algorithm, the unsteady Reynolds-averaged Navier-Stokes equations (URANS) were resolved by means of CFD simulation and the flow performance and the vibration performance were validated with the experiments. The results illustrate that the redesigned impeller with multi-blade could raise the hydraulic performance and reduce the pressure fluctuation inside the pump. When the impeller of each side was laid with the staggered angle of 12 degrees, the pressure distribution tended to be more uniform and the pressure fluctuation was well ameliorated. Through the pressure fluctuation analysis in time domain and frequency domain, the pressure change inside the pumps could be evaluated quantitatively and accurately, hence different pumps could be contrasted in detail. The consequences of this paper could provide reference for pressure fluctuation reduction and vibration performance reinforcement of double-suction centrifugal pumps as well as other vane pumps.

scholarly journals Effects of a Combination Impeller on the Flow Field and External Performance of an Aero-Fuel Centrifugal Pump

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 919
Author(s):  
Jia Li ◽  
Xin Wang ◽  
Yue Wang ◽  
Wancheng Wang ◽  
Baibing Chen ◽  
...  
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Power Plants ◽  
Flow Characteristics ◽  
Significant Feature ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Flow Losses ◽  
Simulation And Experiment ◽  
Aero Engines

Aero-fuel centrifugal pumps are important power plants in aero-engines. Unlike most of the existing centrifugal pumps, a combination impeller is integrated with the pump to improve performance. First, the critical geometrical parameters of the combination impeller and volute are given. Then, the effects of the combination impeller on the flow characteristics of the impeller and volute are clarified by comparing simulation results with that of the conventional impeller, where the effectiveness of the selected numerical method is validated by an acceptable agreement between simulation and experiment. Finally, the experiment is set to test the external performance of the studied pump. A significant feature of this study is that the flow characteristics are significantly ameliorated by reducing the flow losses that emerged in the impeller inlet, impeller outlet, and volute tongue. Correspondingly, the head and efficiency of a combination impeller are higher with comparison to a conventional impeller. Consequently, it is a promising approach in ameliorating the flow field and improving external performance by applying a combination impeller to an aero-fuel centrifugal pump.

scholarly journals Experimental Investigation and Passive Flow Control of a Cavitating Centrifugal Pump

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Spyridon D. Kyparissis ◽  
Dionissios P. Margaris
Keyword(s):  
Flow Control ◽  
Centrifugal Pump ◽  
Leading Edge ◽  
Total Efficiency ◽  
Centrifugal Pumps ◽  
Pump Performance ◽  
Passive Flow Control ◽  
Passive Flow ◽  
Pump Test ◽  
Blade Leading Edge

Passive flow control techniques are used to improve the flow field and efficiency of centrifugal pumps and turbomachines, in general. An important phenomenon that mechanical engineers have to take into account is cavitation. It leads to the decrease of the pump performance and total head. In the present experimental study, a centrifugal pump is investigated in cavitating conditions. A passive flow control is realized using three different blade leading edge angles in order to reduce the cavitation development and enhance the pump performance. The experiments are carried out in a pump test rig specially designed and constructed, along with the impellers. The head drop and total efficiency curves are presented in order to examine the effect of the blade leading edge angle on the cavitation and pump performance. Finally, the vapour distribution along with the blades is illustrated for the tested blade leading edge angles.

An Experimental Study on the Gas Entrainment in Horizontally and Vertically Installed Centrifugal Pumps

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Martin Neumann ◽  
Thomas Schäfer ◽  
André Bieberle ◽  
Uwe Hampel
Keyword(s):  
Centrifugal Pump ◽  
Gas Flow ◽  
Gamma Ray ◽  
Minor Effect ◽  
Centrifugal Pumps ◽  
Flow Conditions ◽  
Two Phase ◽  
Inlet Flow ◽  
Pump Performance ◽  
Gas Entrainment

In this work, we have studied how gas accumulates in an industrial centrifugal pump under various steady-state two-phase flow conditions. Thereby, we considered both horizontal and vertical pump installation positions. Phase fractions within the impeller region of the pump have been quantitatively disclosed using high-resolution gamma-ray computed tomography (HireCT) and applying time-averaged rotation-synchronized CT scanning technique. The study was made for inlet volumetric gas flow rates between 0% and 5%. To account for different inlet flow conditions, which are assumed to occur during unwanted gas entrainment by hollow vortices, we produced disperse and swirling gas–liquid inlet flows. In this way, the influence of inlet flow boundary conditions on the pump performance as well as gas fraction distributions and gas holdup within the impeller wheel region could be successfully analyzed and compared with respect to the impeller alignment. It was shown that the installation position offers only a minor effect on the pump performance in comparison to the inlet flow conditions. In addition, for the first time, thin gas films at the pressure side of the impeller wheel blades could be visualized in an industrial centrifugal pump.

The effect of wear ring clearance on flow field in the impeller sidewall gap and efficiency of a low specific speed centrifugal pump

2017 ◽  
Vol 232 (17) ◽  
pp. 3062-3073 ◽  
Author(s):  
M DaqiqShirazi ◽  
R Torabi ◽  
A Riasi ◽  
SA Nourbakhsh
Keyword(s):  
Flow Field ◽  
Centrifugal Pump ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Volumetric Efficiency ◽  
Centrifugal Pumps ◽  
Disk Friction ◽  
Low Specific Speed ◽  
Overall Efficiency ◽  
Specific Speed

In this paper, the flow in the impeller sidewall gap of a low specific speed centrifugal pump is analyzed to study the effect of wear ring clearance and the resultant through-flow on flow field in this cavity and investigate the overall efficiency of the pump. Centrifugal pumps are commonly subject to a reduction in the flow rate and volumetric efficiency due to abrasive liquids or working conditions, since the wear rings are progressively worn, the internal leakage flow is increased. In the new operating point, the overall efficiency of the pump cannot be predicted simply by using the pump characteristic curves. The flow field is simulated with the use of computational fluid dynamics and the three-dimensional full Navier–Stokes equations are solved using CFX software. In order to verify the numerical simulations, static pressure field in volute casing and pump performance curves are compared with the experimental measurements. The results show that, for the pump with minimum wear ring clearance, the disk friction efficiency is the strongest factor that impairs the overall efficiency. Therefore, when the ring clearance is enlarged more than three times, although volumetric efficiency decreases effectively but the reduction in overall efficiency is remarkably smaller due to improvement in the disk friction losses.

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