Design and Materials for Reduced Pump Corrosion★

CORROSION ◽  
1959 ◽  
Vol 15 (9) ◽  
pp. 41-44
Author(s):  
JACK E. PICCARDO
Keyword(s):  
Corrosion Resistance ◽  
Centrifugal Pump ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Synthetic Materials ◽  
Alloy Steels ◽  
Pump Shaft ◽  
Shaft Seals ◽  
High Degree ◽  
Canned Motor

Abstract Of the pumps used in the chemical and allied industries, about 90 percent are of the centrifugal and diaphragm types. These pumps are required to handle corrosive liquids under conditions of high pressure and high temperature, expensive or hazardous liquids where leakage to atmosphere cannot be tolerated, liquids with solids in suspension, often of an abrasive nature, creating both a corrosion and abrasion problems and extremely corrosive liquids which may be radioactive. Diaphragm type pumps have certain advantages over centrifugal pumps for severe chemical applications because there is no shaft sealing problem, solids in suspension can be handled at relatively low velocities and a high degree of corrosion resistance can be obtained by the use of high alloy steels for the pump body and synthetic materials for diaphragms. Packingless pumps include the so-called canned-motor centrifugal pump in which the pump impeller is mounted on the same shaft as the rotor. Both the rotor and the stator are sealed from the fluid by corrosion resistant cans or shields and the rotor moves in the liquid being pumped. The rotor-impeller shaft is supported on sleeve type bearings submerged in the liquid pumped. Canned-motor pumps usually cannot be applied where the liquid contains solids because of close clearances and possibility of damage to bearings by abrasion. Designs giving longer service life in the conventional centrifugal pump usually include the following: Improved sealing devices where the pump shaft passes through the casing, new alloys or metals for the wetted end to provide a better corrosion resistance, improved elastomers, plastics and ceramics which permit lining entire pumps for a high degree of corrosion resistance. Improved shaft seals are discussed along with a study of new materials available for pump parts, and linings for pumps commonly used in chemical pumping service. 7.3

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.

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 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.

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.

Design and Analysis of Airfoil-Shaped Impeller Blades of Centrifugal Pump

2016 ◽  
Vol 852 ◽  
pp. 539-544
Author(s):  
Parth Shah ◽  
M. Ashwin Ganesh ◽  
Thundil Kuruppa Raj
Keyword(s):  
Centrifugal Pump ◽  
Transport Model ◽  
Turbulence Models ◽  
Suction Side ◽  
3D Analysis ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Outlet Pressure ◽  
Shear Stress Transport Model ◽  
Centrifugal Pump Impeller

This paper deals with a comparative study of the outlet pressure-energy between a conventional and normal blade impeller and an airfoil-shaped blade impeller of a centrifugal pump. Although the volute casing is an important component along with an impeller [1], the present comparative analysis makes the volute casing redundant to the study, hence neglected. All centrifugal pumps are usually designed and manufactured using backward swept blades with equal camber on the top and bottom sides. An increased camber on the top side is an ideal trait for a lift generating airfoil. The purpose is to implement the principle of lift generation of airfoil for centrifugal pumps. As a result, a local suction side and pressure side can be visualized using CFX-post processor. The 3D analysis of such a centrifugal pump impeller is designed in SOLIDWORKS® and analyzed using ANSYS® CFX. The SST (Menter’s Shear Stress Transport) model is used as it combines both the k-ω and k-ε turbulence models.

Improvement of Centrifugal Pump Performance by Using Different Impeller Diffuser Angles with and Without Vanes

2018 ◽  
Vol 35 (4) ◽  
pp. 577-589 ◽  
Author(s):  
D. Khoeini ◽  
E. Shirani ◽  
M. Joghataei
Keyword(s):  
Centrifugal Pump ◽  
Experimental Studies ◽  
High Flow ◽  
Divergence Angle ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Vaned Diffuser ◽  
Flow Rates ◽  
Operating Region ◽  
Overall Efficiency

ABSTRACTThis study aims at improving the performance of a centrifugal pump by using different angular diffusers on the downstream side of the centrifugal pump impeller. Numerical and experimental studies have been carried out on different vaned and non-vaned diffuser with three different wall divergence angle (α) of 0°, 5° and 10° to achieve that purpose. The data analyses show good agreement between the numerical and experimental results. They reveal profound effect of the divergence angle (α) of angular vaned diffuser on the head and overall efficiency of centrifugal pumps especially at high flow rates as they broaden operating region of the centrifugal pump. In fact it is found that the head and overall efficiency of impeller with vaned diffuser α = 10° enhance by 15.4 and 9 percent respectively compared to that of centrifugal pump with no vaned diffuser at high flow rates. Furthermore the head and overall efficiency of impeller with vaned diffuser α = 10° increase by 5.7 and 7 percent respectively in comparison with the impeller with vaned diffuser α = 0°.

Experimental Investigation on Pressure Fluctuation Reduction in a Double Suction Centrifugal Pump: Influence of Impeller Stagger and Blade Geometry

2020 ◽  
Vol 142 (4) ◽  
Author(s):  
Yongshun Zeng ◽  
Zhifeng Yao ◽  
Fujun Wang ◽  
Ruofu Xiao ◽  
Chenglian He
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuation ◽  
High Amplitude ◽  
Operating Conditions ◽  
Center Frequency ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Axial Forces ◽  
Large Peak ◽  
Blade Geometry

Abstract The reduction in pressure fluctuation can suppress noise, balance the radial and axial forces, and restrain the vibration level of a centrifugal pump. Impeller stagger and blade geometry influence the pressure fluctuation characteristics of double suction centrifugal pumps. In the present investigation, the pressure fluctuation characteristics of the baseline impeller, the staggered impeller, and the blade geometry modified impeller were investigated experimentally under design and off-design operating conditions. The frequency spectrum was analyzed by fast Fourier transform (FFT) and continuous wavelet transform (CWT) methods. The broadband frequencies are defined quantitatively and analyzed emphatically. The significant linear relationship between the center frequency of the broadband frequencies and the flowrate is discovered for the first time. The center frequency decreases as the flowrate increases. The linearity varies below and above the design flowrate. When the discrete frequencies are in range of the broadband frequencies, a high amplitude of pressure fluctuation occurs. This could explain the large peak-to-peak value of the pressure fluctuation at 1.24Qn, which may be due to the coincidence between broadband frequencies and the components at the frequencies fr and 2fr. Both the staggered impeller and the blade geometry modified impeller can reduce the level of pressure fluctuation; in particular, it is reduced to 35% and 13% compared to that of baseline impeller near the volute tongue region under the design flowrate, respectively. The staggered impeller and the blade geometry can obviously affect the decreasing slopes between the center frequencies and the flowrate.

Compendious Review on “Internal Flow Physics and Minimization of Flow Instabilities Through Design Modifications in a Centrifugal Pump”

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
Neeta A. Mandhare ◽  
K. Karunamurthy ◽  
Saleel Ismail
Keyword(s):  
Centrifugal Pump ◽  
Pressure Fluctuations ◽  
Internal Flow ◽  
Boundary Layer Separation ◽  
Industrial Applications ◽  
Centrifugal Pumps ◽  
Pump Impeller ◽  
Design Modification ◽  
Flow Physics ◽  
And Performance

Centrifugal pumps are one of the significant consumers of electricity and are one of the most commonly encountered rotodynamic machines in domestic and industrial applications. Centrifugal pumps operating at off-design conditions are often subject to different periodic flow randomness, which in turn hampers functionality and performance of the pump. These limitations can be overcome by modification in the conventional design of different components of a centrifugal pump, which can assuage flow randomness and instabilities, reconstitute flow pattern and minimize hydraulic flow losses. In this article, flow vulnerabilities like pressure and flow inconsistency, recirculation, boundary layer separation, adverse rotor–stator interaction, and the effects on operation and performance of a centrifugal pump are reviewed. This article also aims to review design modification attempts made by different researchers such as impeller trimming, rounding, geometry modification of different components, providing microgrooves on the impeller and others. Based on the findings of this study, it is concluded that some design modifications of the impeller, diffuser, and casing result in improvement of functionality, efficiency, and reduction in pressure fluctuations, flow recirculation, and vibrations. Design modifications should improve the performance without hampering functionality and useful operational range of the pump. Considerable research is still necessary to continue understanding and correlating flow physics and design modifications for the pump impeller, diffuser, and casing.

scholarly journals The simulation of the service life of the rotary shaft of a centrifugal pump

2019 ◽  
Vol 287 ◽  
pp. 01025
Author(s):  
Madina Isametova ◽  
Rollan Nussipali ◽  
Aysen Isametov
Keyword(s):  
Service Life ◽  
Centrifugal Pump ◽  
Safety Factor ◽  
Operating Time ◽  
Radial Force ◽  
Life Safety ◽  
Centrifugal Pumps ◽  
Computer Technique ◽  
Rotor Shaft ◽  
Pump Shaft

The article describes an automated calculation of such an essential part of a centrifugal pumps the rotor shaft, so the highest level CAD NASTRAN system PATRAN module was used for the analysis. The computational mechanical scheme was drawn up, the axial and radial force acting on the impeller and the pump shaft were determined. The stress for the maximum feed case are determined. The results of the automated strength calculation were used for further analysis of the service life of the rotor shaft of a centrifugal pump. A computer technique for determining the service life of the shaft is given, taking into account the technological, mechanical conditions of operation and taking into account the projected service life equal to the lifetime of the uranium well. Using the automated MSC FATIGUE module, the number of loading cycles was determined, the service life safety factor was determined, which showed the efficiency of the pump throughout the entire operating time of the uranium well.

scholarly journals Effect of Impeller Diameter on Dynamic Response of a Centrifugal Pump Rotor

Vibration ◽  
2021 ◽  
Vol 4 (1) ◽  
pp. 117-129
Author(s):  
Alireza Shooshtari ◽  
Mahdi Karimi ◽  
Mehrdad Shemshadi ◽  
Sareh Seraj
Keyword(s):  
Dynamic Response ◽  
Centrifugal Pump ◽  
Model Updating ◽  
Equations Of Motion ◽  
Beam Theory ◽  
Oil Refinery ◽  
Centrifugal Pumps ◽  
Concentrated Mass ◽  
Inverse Dynamic ◽  
Pump Impeller

This paper investigates the effect of impeller diameter on the dynamic response of a centrifugal pump using an inverse dynamic method. For this purpose, the equations of motion of the shaft and the impeller are derived based on Timoshenko beam theory considering the impeller as a concentrated mass disk. For practical modeling, the model of Jones and Harris is added to the equation to include the effect of bearings. As a case study, the model is applied to a process pump used in an oil refinery. Computing the eigenvalues of the model and comparing them with the natural frequencies of the structure, the model updating of the problem is performed through an indirect method. Three impellers with different diameters are applied to the updated model. The results show that increasing the diameter of the pump impeller can increase the amplitude of vibration up to 52% at critical speeds of the rotor. It is found that in addition to the hydraulic condition and efficiency, the impeller diameter should be considered as an important factor in the selection of centrifugal pumps.

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