scholarly journals A New Prediction Method for the Complete Characteristic Curves of Centrifugal Pumps

Energies ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 8580
Author(s):  
Huokun Li ◽  
Hongkang Lin ◽  
Wei Huang ◽  
Jiazhen Li ◽  
Min Zeng ◽  
...  
Keyword(s):  
Mathematical Model ◽  
Centrifugal Pump ◽  
Prediction Accuracy ◽  
Small Deviation ◽  
Measured Data ◽  
Centrifugal Pumps ◽  
Operating Characteristics ◽  
Pump Impeller ◽  
Pump Station ◽  
Specific Speed

Complete pump characteristics (CPCs) are the key for establishing pump boundary conditions and simulating hydraulic transients. However, they are not normally available from manufacturers, making pump station design difficult to carry out. To solve this issue, a novel method considering the inherent operating characteristics of the centrifugal pump is therefore proposed to predict the CPCs. First, depending on the Euler equations and the velocity triangles at the pump impeller, a mathematical model describing the complete characteristics of a centrifugal pump is deduced. Then, based on multiple measured CPCs, the nonlinear functional relationship between the characteristic parameters of the characteristic operating points (COPs) and the specific speed is established. Finally, by combining the mathematical model with the nonlinear relationship, the CPCs for a given specific speed are successfully predicted. A case study shows that the predicted CPCs are basically consistent with the measured data, showing a high prediction accuracy. For a pump-failure water hammer, the simulated results using the predicted CPCs are close to that using the measured data with a small deviation. This method is easy to program and the prediction accuracy meets the requirements for hydraulic transient simulations, providing important data support for engineering design.

scholarly journals Optimal Design of Slit Impeller for Low Specific Speed Centrifugal Pump Based on Orthogonal Test

2021 ◽  
Vol 9 (2) ◽  
pp. 121
Author(s):  
Yang Yang ◽  
Ling Zhou ◽  
Hongtao Zhou ◽  
Wanning Lv ◽  
Jian Wang ◽  
...  
Keyword(s):  
Numerical Simulation ◽  
Centrifugal Pump ◽  
Large Scale ◽  
Internal Flow ◽  
Orthogonal Test ◽  
Centrifugal Pumps ◽  
Initial Model ◽  
Low Specific Speed ◽  
Specific Speed ◽  
Four Levels

Marine centrifugal pumps are mostly used on board ship, for transferring liquid from one point to another. Based on the combination of orthogonal testing and numerical simulation, this paper optimizes the structure of a drainage trough for a typical low-specific speed centrifugal pump, determines the priority of the various geometric factors of the drainage trough on the pump performance, and obtains the optimal impeller drainage trough scheme. The influence of drainage tank structure on the internal flow of a low-specific speed centrifugal pump is also analyzed. First, based on the experimental validation of the initial model, it is determined that the numerical simulation method used in this paper is highly accurate in predicting the performance of low-specific speed centrifugal pumps. Secondly, based on the three factors and four levels of the impeller drainage trough in the orthogonal test, the orthogonal test plan is determined and the orthogonal test results are analyzed. This work found that slit diameter and slit width have a large impact on the performance of low-specific speed centrifugal pumps, while long and short vane lap lengths have less impact. Finally, we compared the internal flow distribution between the initial model and the optimized model, and found that the slit structure could effectively reduce the pressure difference between the suction side and the pressure side of the blade. By weakening the large-scale vortex in the flow path and reducing the hydraulic losses, the drainage trough impellers obtained based on orthogonal tests can significantly improve the hydraulic efficiency of low-specific speed centrifugal pumps.

Comparison of Inlet Curved Disk Arrangements for Suppression of Recirculation in Centrifugal Pump Impellers

2016 ◽  
Author(s):  
Munther Y. Hermez ◽  
Badih A. Jawad ◽  
Liping Liu ◽  
Vernon Fernandez ◽  
Kingman Yee ◽  
...  
Keyword(s):  
Centrifugal Pump ◽  
High Speed ◽  
Operating Cost ◽  
Three Dimensional ◽  
Centrifugal Pumps ◽  
Unstable Flow ◽  
Pump Impeller ◽  
Flow Rates ◽  
Flow Recirculation ◽  
Flow Field Characteristics

The present work aims to numerically study the inlet flow recirculation and modified impeller interaction in a centrifugal pump. An optimization of modified shrouded impeller with curved disk arrangement to suppress the unsteady flow recirculation is pursued. This modification will enhance the impeller characteristics with a wider operation range at both low and high flow rates in a high speed centrifugal pump type. The unstable flow in the centrifugal pumps is a common problem that leads to damage in the pump’s internal parts, consequently increases the operating cost. At certain flow rates, generally below the Best Efficiency Point (BEP), all centrifugal pumps are subject to internal recirculation occurs at the suction and discharge areas of the impeller. For decades, experimental work has been done to investigate the complex three-dimensional flow within centrifugal pumps impellers, before computational work gains momentum due to advancement of computing power and improved numerical codes. In this study the impeller with a curved disk arrangement has been investigated by using a three-dimensional Navier-Stokes code with a standard k-ε turbulence model. The purpose is to evaluate and select the optimum impeller modification that would increase the pump suction flow rate range. Three-dimensional numerical Computational Fluid Dynamics (CFD) tools are used to simulate flow field characteristics inside the centrifugal pump and provide critical hydraulic design information. In the present work, ANSYS v.16.1 Fluent solver is used to analyze the pressure and velocity distributions inside impeller suction and discharge passages. The ultimate goal of this study is to manufacture and validate the most optimized and efficient centrifugal pump impeller with a curved disk. The best case curve identifies the highest increase of total pressure difference by 22.1%, and highest efficiency by 92.3% at low flowrates.

scholarly journals Numerical Simulation of 3D Solid-Liquid Turbulent Flow in a Low Specific Speed Centrifugal Pump: Flow Field Analysis

2014 ◽  
Vol 6 ◽  
pp. 814108 ◽  
Author(s):  
Baocheng Shi ◽  
Jinjia Wei
Keyword(s):  
Turbulent Flow ◽  
Centrifugal Pump ◽  
Centrifugal Pumps ◽  
Numerical Convergence ◽  
Phase Calculation ◽  
Low Specific Speed ◽  
Specific Speed ◽  
3D Solid ◽  
Solid Liquid ◽  
Numeral Simulation

For numerically simulating 3D solid-liquid turbulent flow in low specific speed centrifugal pumps, the iteration convergence problem caused by complex internal structure and high rotational speed of pump is always a problem for numeral simulation researchers. To solve this problem, the combination of three measures of dynamic underrelaxation factor adjustment, step method, and rotational velocity control means according to residual curves trends of operating parameters was used to improve the numerical convergence. Numeral simulation of 3D turbulent flow in a low specific speed solid-liquid centrifugal pump was performed, and the results showed that the improved solution strategy is greatly helpful to the numerical convergence. Moreover, the 3D turbulent flow fields in pumps have been simulated for the bottom ash-particles with the volume fraction of 10%, 20%, and 30% at the same particle diameter of 0.1 mm. The two-phase calculation results are compared with those of single-phase clean water flow. The calculated results gave the main region of the abrasion of the impeller and volute casing and improve the hydraulic design of the impeller in order to decrease the abrasion and increase the service life of the pump.

scholarly journals Optimization and Analysis of Centrifugal Pump considering Fluid-Structure Interaction

2014 ◽  
Vol 2014 ◽  
pp. 1-9 ◽  
Author(s):  
Yu Zhang ◽  
Sanbao Hu ◽  
Yunqing Zhang ◽  
Liping Chen
Keyword(s):  
Centrifugal Pump ◽  
Fluid Structure Interaction ◽  
Kriging Model ◽  
Geometrical Parameters ◽  
Centrifugal Pumps ◽  
Transient Vibration ◽  
Pump Impeller ◽  
Fluid Structure ◽  
Structure Interaction ◽  
Vibration Performance

This paper presents the optimization of vibrations of centrifugal pump considering fluid-structure interaction (FSI). A set of centrifugal pumps with various blade shapes were studied using FSI method, in order to investigate the transient vibration performance. The Kriging model, based on the results of the FSI simulations, was established to approximate the relationship between the geometrical parameters of pump impeller and the root mean square (RMS) values of the displacement response at the pump bearing block. Hence, multi-island genetic algorithm (MIGA) has been implemented to minimize the RMS value of the impeller displacement. A prototype of centrifugal pump has been manufactured and an experimental validation of the optimization results has been carried out. The comparison among results of Kriging surrogate model, FSI simulation, and experimental test showed a good consistency of the three approaches. Finally, the transient mechanical behavior of pump impeller has been investigated using FSI method based on the optimized geometry parameters of pump impeller.

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.

Numerical Simulation of Hysteresis on Head/Discharge Characteristics of a Centrifugal Pump

2003 ◽  
Author(s):  
Masamichi Iino ◽  
Kazuhiro Tanaka ◽  
Kazuyoshi Miyagawa ◽  
Takeshi Okubo
Keyword(s):  
Numerical Simulation ◽  
Hysteresis Loop ◽  
Centrifugal Pump ◽  
Characteristic Curve ◽  
Swirl Flow ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Discharge Characteristics ◽  
Discharge Characteristic ◽  
Partial Load

The objectives of the present study were to investigate influences of fins, set in a suction part, on the positive slope and hysteresis loop in head/discharge characteristic curves of centrifugal pumps in the experiment as well as in the numerical prediction. The fins were located in upstream side of a pump impeller to suppress swirl flow occurring before the impeller inlet at partial load operation. We had two kinds of centrifugal pump with/without the fins, the number of which is 16. These two centrifugal pumps had a shrouded impeller with 7 blades and a diffuser with 20 guide vanes with the same configuration. In the experiment, the pump with them had a large hysteresis loop at partial load operation in the head/discharge characteristic curve, although the pump without them had no hysteresis loop. In the numerical simulation based on periodic flow, the incompressible turbulent flow field was calculated for partial blade-passages with periodic boundary conditions. As a result, the simulated characteristics had the same tendencies as the experimental results. Furthermore, the causes of the discontinuous head/discharge characteristics depending on the direction of partial load operation were clarified through calculating and comparing the internal flow fields in the cases with/without the fins. The pumps had the large backflow and recirculation areas in two places, one of which was near the shroud at the impeller inlet including the fins area and another near the central part of the diffuser. The difference in the hysteresis loop between with and without the fins was caused by the existence of the fins, which suppressed or promoted the backflow at the impeller.

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