Multi-stage, vertical, seal-less, non-metallic magnetic drive, centrifugal pumps

World Pumps ◽  
1998 ◽  
Vol 1998 (383) ◽  
pp. 10
Keyword(s):  
Centrifugal Pumps ◽  
Multi Stage ◽  
Magnetic Drive

Measurements of Rotordynamic Forces on an Artificial Heart Pump Impeller

2007 ◽  
Vol 129 (11) ◽  
pp. 1422-1427 ◽  
Author(s):  
Takayuki Suzuki ◽  
Romain Prunières ◽  
Hironori Horiguchi ◽  
Tomonori Tsukiya ◽  
Yoshiyuki Taenaka ◽  
...  
Keyword(s):  
Artificial Heart ◽  
Journal Bearing ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Fluid Forces ◽  
Heart Pump ◽  
Wide Range ◽  
Artificial Hearts ◽  
Rotordynamic Forces ◽  
Magnetic Drive

In centrifugal pumps for artificial hearts, a magnetic drive with lightly loaded journal bearing system is often used. In such a system, the rigidity of the bearing is small and the impeller usually rotates over the critical speed. In such cases, the rotordynamic fluid forces play an important role for shaft vibration. In the present study, the characteristics of the rotordynamic fluid forces on the impeller were examined. The rotordynamic fluid forces were measured in the cases with/without the whirling motion. It was found that the rotordynamic forces become destabilizing in a wide range of positive whirl. The effect of leakage flow was also examined.

Centrifugal Pump Leak-Free Technology Introduction and Its Applications in EPR Nuclear Power Plant

2010 ◽  
Author(s):  
Guohui Cong ◽  
Ling Zhang
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Centrifugal Pump ◽  
Nuclear Power ◽  
Operating Conditions ◽  
Critical Conditions ◽  
Mechanical Seal ◽  
Centrifugal Pumps ◽  
Canned Motor ◽  
Magnetic Drive

Environmental protection requirement is more and more critical now, and it increases the request to prevent dangerous liquid to leak outside in nuclear power plant too. Centrifugal pumps are the most important active equipments in nuclear power plant, but there is a shaft clearance between rotor and stator of centrifugal pump. The shaft clearance can lead pumped fluid to the outside, so the environment may be polluted by the leakage. In some critical conditions such as transferring high radioactive fluid in the pump, the leakage shall be totally forbidden. So solutions have to be found to make centrifugal pumps totally leak-free for applications in nuclear power plant. Normally there are three leak-free technologies for centrifugal pumps: mechanical seal with auxiliary system, canned motor and magnetic drive. In this paper, all the three leak-free technologies and some of their applications in EPR 3rd generation PWR nuclear power plants are presented and discussed. The results show that in EPR nuclear power plant, canned motor pumps can be preferably used for strict environmental requirement of leak-free if the pump power and operating conditions are applicable. For other conditions, pumps with double mechanical seal can also be used with additional sealing water system support. For centrifugal pumps with magnetic drive are not so applicable in high pressure condition, and the safety aspect is weaker than canned motor pumps, generally they are not used in EPR nuclear power plant at present.

Axial Thrust Prediction for a Multi-Stage Centrifugal Pump

2017 ◽  
Author(s):  
K. A. J. Bruurs ◽  
B. P. M. van Esch ◽  
M. S. van der Schoot ◽  
E. J. J. van der Zijden
Keyword(s):  
Hybrid Method ◽  
Setup Time ◽  
Correct Selection ◽  
Centrifugal Pumps ◽  
Axial Thrust ◽  
Multi Stage ◽  
Empirical Relations ◽  
Cfd Method ◽  
Semi Empirical ◽  
Computer Resources

The prediction of axial thrust for centrifugal pumps has been an important topic for many years. This is especially the case for multi-stage pumps with opposed or inline impellers, as the correct selection of balancing device(s) and bearings depends highly on the accuracy of the calculated thrust. Up till now, many investigations regarding axial thrust have focused on fully analytical or (semi-)empirical relations while others have tried to predict the axial thrust using CFD simulations. Full analytical or empirical methods tend to give poor results or need tuning for each specific pump, while the full CFD methods are costly in both setup time and computer resources. This paper presents a hybrid method to calculate the axial thrust of a multi-stage pump with an inline impeller design. The hybrid method combines analytical methods and CFD to reduce the required setup time and computation costs. The CFD calculation of the main flow is used as a boundary condition for the semi-empirical models for the side chambers and the inter-stage seals, such that these tight regions can be excluded from the CFD calculation. To verify and validate the hybrid method, results are compared with measurements and with full CFD calculations that include the side chambers and seals. These results show that the hybrid method and the full CFD method give comparable results, but there is still some difference with the measurements.

Numerical Modeling of Static and Rotordynamic Characteristics for Three Types of Helically-Grooved Liquid Annular Seals

2019 ◽  
Author(s):  
Zhigang Li ◽  
Zhi Fang ◽  
Jun Li ◽  
Zhenping Feng
Keyword(s):  
Perturbation Method ◽  
Leakage Flow ◽  
Centrifugal Pumps ◽  
Flow Rates ◽  
Force Coefficients ◽  
Numerical Predictions ◽  
Multi Stage ◽  
Annular Seal ◽  
Helical Grooves ◽  
Annular Seals

Abstract This paper deals with numerical predictions of the leakage flow rates, drag power and rotordynamic force coefficients for three types of helically-grooved liquid annular seals, which include a liquid annular seal with helically-grooved stator (GS/SR seal), one with helically-grooved rotor (SS/GR seal), and one with helical grooves on stator and rotor (GS/GR seal). These seals are frequently used for multiple-stage centrifugal pumps as they have the advantage of low leakage (even to zero) due to the “pumping effect” of the helical grooves. However, the static and rotordynamic characteristics of helically-grooved liquid annular seals still are not fully understood, and even more pronounced is the lack of effective numerical models in the literature. A novel transient CFD-based perturbation method was proposed for the predictions of the leakage flow rates, drag power and rotordynamic force coefficients of helically-grooved liquid annular seals. This method is based on the unsteady Reynolds-Averaged Navier–Stokes (RANS) solution with the mesh deformation technique and the multiple reference frame theory. The time-varying fluid-induced forces acting on the rotor/stator surface were obtained as a response to the time-dependent perturbation of the seal stator surface with the periodic motion, based on the multiple-frequency elliptical-orbit stator whirling model. The frequency-independent rotordynamic force coefficients were determined using curve fit and Fast Fourier Transform (FFT) in the frequency domain. The CFD-based method was adequately validated by comparisons to the published experiment data of leakage flow rates and fluid response forces for three types of helically-grooved liquid annular seals. Based on the transient CFD-based perturbation method, numerical results of the leakage flow rates, drag powers and rotordynamic force coefficients were presented and compared for three types of helically-grooved liquid annular seals at five rotational speeds (n = 0.5 krpm, 1.0 krpm, 2.0 krpm, 3.0 krpm and 4.0 krpm), paying special attention to the effective stiffness coefficient and effective damping coefficient. Results show that the GS/GR seal has the best sealing capability, followed by the GS/SR seal and then the SS/GR seal. The leakage flow rate of all three helically-grooved seals monotonically decreases with the increasing rotational speed. The GS/SR seal possesses the best stiffness and damping capability, followed by the SS/GR seal and then the GS/GR seal. Rotordynamic instability problems are more likely caused by the GS/GR seal in multi-stage centrifugal pumps. From a rotordynamic viewpoint, the GS/SR helically-grooved liquid annular seal is a better seal concept for multi-stage centrifugal pumps.

Effects of Viscosity and Two Phase Liquid–Gas Fluids on the Performance of Multi-Stage Centrifugal Pumps

2010 ◽  
Author(s):  
Brown ‘Lyle’ Wilson ◽  
Ketan Sheth ◽  
Donn Brown
Keyword(s):  
Test Facility ◽  
Centrifugal Pumps ◽  
Two Phase ◽  
Void Fractions ◽  
Multi Stage ◽  
Significant Difference ◽  
Phase Liquid ◽  
Intake Pressure ◽  
Two Phases ◽  
Safety Considerations

The paper reports on developmental research on the effects of viscosity and two phases, liquid–gas fluids on ESPs which are multi stage centrifugal pumps for deep bore holes. The test facility work was performed using pumps with ten or more stages moving fluids with viscosity from 2 to 2500 cP at various speed, intake pressure and Gas Void Fractions (GVF). For safety considerations the injected gas was restricted to nitrogen or air. The results are a series of curves representing the performance degradation of the pump. Note that in some cases the pump performances actually improved with increasing viscosity. The resulting information will allow a better understanding and more accurate prediction of performance than has been previously available. The data indicates a significant difference in performance correction when compared to the information available from the Hydraulics Institute.

Magnetic drive for centrifugal pumps

1998 ◽  
Vol 34 (6) ◽  
pp. 389-396
Author(s):  
B. S. Zakharov
Keyword(s):  
Centrifugal Pumps ◽  
Magnetic Drive

Critical Rotation Speed Calculation and Application Development of Multi-Stage Centrifugal Pumps for Mining

2011 ◽  
Vol 130-134 ◽  
pp. 1119-1122
Author(s):  
Wei Li ◽  
Wei Dong Shi ◽  
Xiao Ping Jiang ◽  
Yan Xu
Keyword(s):  
Rotation Speed ◽  
Computational Method ◽  
Secondary Development ◽  
Centrifugal Pumps ◽  
Operational Environment ◽  
Application Development ◽  
Critical Rotation ◽  
Multi Stage ◽  
Pump Shaft ◽  
Critical Rotation Speed

Multi-stage centrifugal pumps for mining are widely used in mining and smelting industry. The operational environment in coal mine sewage is very harsh, so pump shaft and bearing failure happens frequently. In order to avoid disaster damage caused by failure of the pump shaft due to resonance, it is quite necessary and urgent to calculate critical rotation speed of the pump shaft. A calculation program of critical rotation speed for multi-stage centrifugal pumps for mining was developed using the secondary development tool of Object ARX, to give the computational method of the pump shaft load and static deflection and to achieve calculation of the critical speed, and which avoided the disadvantage of the traditional method. The practical application indicates that the program of critical rotation speed is convenient, intuitive and calculation accurate. It not only improves the work efficiency, but also reduces the labor intensity, so the program will have a good application prospect.

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