Application Of Centrifugal Pumps Research Articles

IMPROVING THE PERFORMANCE INDICATOR OF CENTRIFUGAL PUMPS

This article is devoted to the research and development of methods to improve the performance of centrifugal pumps. Centrifugal pumps are key elements in various industrial and technical systems, ensuring efficient transportation of liquids. This article reviews the operation of centrifugal pumps, shows the scheme of the pumping part of the centrifugal type equipment, the scheme of the cantilever type centrifugal pump and describes their main components. Further, the factors affecting pump performance, including fluid viscosity and operating conditions, are analyzed, and methods for improving performance are described in detail, including design optimization, the use of new materials and modern technologies, as well as speed control and monitoring of pump condition. The advantages and disadvantages of centrifugal pumps are noted, the concept of what the operation of this equipment is based on is given, and the fields of application of centrifugal pumps are considered. In order to improve the operation of pumps, the article includes a table showing the existing problems in the operation of the pumps described by the author, the correction of which will lead to positive results, namely, an increase in quantitative and qualitative performance indicators. Further, in the article, a color diagram is shown, which shows the share distribution, that is, the percentage of damage to the structural elements of centrifugal pumps. To improve the reliability and efficiency of operation of centrifugal pumps, the article discusses in detail two ways to solve this task. The first way to solve the problem is the development and manufacture of new, namely more advanced pumps in design, which most often requires significant financial costs, and the second way was noted the modernization of already functioning equipment, which allows you to reduce your own costs and thereby ensure the implementation of energy saving programs. Based on the analysis and the examples considered, it is concluded that an increase in the performance of centrifugal pumps can lead to a significant improvement in efficiency and cost reduction. Keywords: centrifugal pump, productivity, performance indicators, optimization, materials, control.

The influence of ring clearance on the performance of a double-suction centrifugal pump

Due to the complex structure of a double-suction pump's suction chamber, the flow in the pump's cavity is often ignored in numerical simulations because of difficulties in structured hexahedral meshing. However, the wear ring clearance interlinking the pump chamber leads the fluid at the impeller inlet directly to the impeller area. This significantly impacts the pump's internal flow field, so the influence of the clearance on the internal flow of a double-suction pump cannot be ignored. This paper develops four three-dimensional double-suction pump models with different wear ring clearances to investigate their influence on pump performance, and structured hexahedral meshes were used for all the computational domains. The clearances varied from 0.2 to 0.5 mm in 0.1 mm increments. The influences of the clearance on the energy loss, external characteristics, and internal flow field distribution of the pump were simulated via a verified computational fluid dynamics method. The results show that the wear ring leakage decreases with the flow rate and increases with wear ring clearance. The increase in backflow leads to an internal flow disorder inside the impeller, resulting in a decreased head and efficiency. Energy loss is mainly caused by increasing the turbulence entropy production with an increasing wear ring clearance. Also, the low-pressure region in the pump cavity expands to the volute with increasing clearance, and the impeller outlet pressure decreases. This study's research on wear ring clearance provides a reference for the design and application of double-suction centrifugal pumps.

CFD Investigation on Three Turbulence Models for Centrifugal Pump Application

CFD Investigation on Three Turbulence Models for Centrifugal Pump Application

Study on Leakage Performance and Rotordynamic Characteristics of a Novel Semi-Y Type Labyrinth Seal

A new type of labyrinth seal with semi-Y of rotor teeth (SYLS) is proposed in this paper. The rationality and accuracy of the numerical model are validated by the experimental results, and the static characteristics are investigated. Furthermore, the effects of pressure drop, rotation speed, tilt angle, and tip clearance on the dynamic coefficients and stability are also studied in detail. The results imply that the novel SYLS structure generally has better leakage and stability performance compared with the traditional labyrinth seal. The maximum error applied in the numerical simulation is only 2.81%, and the worst leakage occurs when the tilt angle is 70° for the SYLS structure due to the smaller vortex dissipation. Moreover, the novel SYLS structure shows the best stability when the tilt angle is 45°. The novel SYLS structure and corresponding results can provide a reference for the research and design for labyrinth seal and the application of centrifugal pump.

Review of the Hydraulic and Structural Design of High-Speed Centrifugal Pumps

In recent years, much attention has been paid to the application of high-speed centrifugal pumps; still, the development of this pump faces several challenges. In order to obtain a more comprehensive understanding of the high-speed centrifugal pump, this paper reviewed the engineering application, technical challenges, and feasible solutions of this pump from the aspects of hydraulic design, including cavitation, hydraulic excitation, efficiency issue at an ultra-low specific speed, and the solution to these problems. The current state of the structural design of the high-speed centrifugal pump was briefly described in addition. For the faults in the existing high-speed centrifugal pump, some research studies on pump monitoring were presented. Finally, the status and shortcomings of the design of the pump were simply analyzed and summarized. It is hoped that this study can provide some references for the design and practical usage of high-speed centrifugal pumps.

Application of CFD to Improve on Reliability and Efficiency of Centrifugal Pump for Oil and Gas Processing Plant

Centrifugal pump is one of the standard pump specification uses in process industries for qualitative and quantitative fluid transfer. Most industrial application of centrifugal pump has mechanical configuration problems that resulted to pump inefficiency and malfunctions. Fault or bad design pumps are characterized due to quality engineering design which prompted this investigation. In this study, CFD code was used to simulate pump efficiency and compared with real experimental studies. Within the limit of simulation experimental error, it was found that, the centrifugal pump was designed within the constraint of pumping at a flow rate of 0.04 m3/s and at a Head of 55-70 m. After the design calculations, the system was model and drawn in SOLIDWOKS, it was found that the pump was given the required material from the software material library in line with the design specifications and parameters using local materials. The performance of the pump was simulated and evaluated to have a flow rate of 0.043 m3/s, velocity of 8.2 m/s with a head of 70 m and various efficiencies ranging from 68.45 - 81.61%. After the analysis was done, 590 it was identified to be the optimum impeller outlet blade angle in which volumetric efficiency and hydraulic efficiency is maximum. The efficiency pressure ratio has also increased; therefore the pump head also increase. Keywords: Flow, pump, efficiency and reliability

COMPARISON OF ENERGY CONSUMPTION OF VARIOUS ELECTRICAL MOTORS OPERATING IN A PUMPING UNIT

Purpose. Comparative analysis of energy consumption of various types electric motors in fixed speed centrifugal industrial pump applications is carried out. The purpose of the analysis is to choose the most efficient motor in the considered application. It is assumed that hydraulic flow of the pump is adjusted by throttling. The rated power of the pump unit is 2.2 kW. Direct on line motors of various energy efficiency classes from various manufacturers are considered: induction motors with permanent magnets on the rotor of IE4 class and squirrel cage induction motors of IE3 and IE4 classes. Methodology. Assessment of energy consumption of the motors is carried out based on the catalogue data from manufacturers of the pump and the motors. Pump hydraulic equations, interpolation of motor catalogue data and statistical data are also used. Results. The following values have been obtained: annual and daily energy consumption of the motors and electricity cost savings comparing with the least effective motor considered. Practical value. The following practical consideration are presented based on the theoretical results: choosing the motor based only on its IE efficiency class according to IEC 60034-30-1 is not enough to ensure the minimum energy consumption of pump units with variable flow during the load cycle. In addition, the energy consumption may be higher in the case of permanent magnet motors of IE4 class in comparison with induction motors of IE4 or even IE3 class. Therefore, it is necessary to take into account efficiency of the motors at underload and it is needed to calculate the energy consumption during the actual load cycle. It should be noted, that the existing approach based on the Energy Efficiency Index (EEI) calculation does not provide information about absolute values of energy savings and cost savings, in contrast to the described approach. While choosing motors to run in the considered application it is also important to take into account that the motors with permanent magnets on the rotor have significantly higher price and very restricted starting capabilities comparing with induction motors. In addition, the production of rare earth magnets causes a significant environmental damage.

Performance Analysis and Cavitation Prediction of Centrifugal Pump Using Various Working Fluids

Background: The application of centrifugal pumps is found in domestic and petrochemical industries. Industrial centrifugal pumps are designed and tested using water as working fluid before supplied to industries, as water is commonly available. However, centrifugal pumps are used in industries for various applications, which involve the handling of fluids other than water- like saline-water, crude oil, gasoline, etc. Consequently, hydraulic performance of the pump differs from the designed and tested values and pump performance becomes unpredictable. Cavitation characteristics of the pump handling different fluids other than water are also changed and many a time, cavitation starts prematurely. As a result, the operating cost of pump is increased. Objective: A CFD based computational analysis of a single-stage, single-entry industrial centrifugal pump having double-volute casing is carried out to compare the performance and cavitation characteristics for various working fluids, namely water, saline water with varying salinity, gasolene and crude oil. Methods: Multiple Reference Frame method (MRF) available in Reynolds-Averaged Navier-Stokes (RANS) equations based CFD solver Ansys-CFX is used in the present study. CFD simulation is carried out for five flow rates with Standard k-ε turbulence model. Rayleigh-Plesset equation describing the growth of a single vapor bubble in a liquid is used for predicting the cavitation flow behaviour. Results: Minimum static pressure is computed at the suction side of saline water as compared to the other working fluids studied here. Hydraulic efficiency of crude oil is found to be the lowest as compared to other fluids. Supercavitation (excessive formation of vapor bubbles and sudden drop in head up to 3%) starts early for saline water with 40g/kg salinity. Conclusion: The results show little variation in pump efficiency when water and saline water are used as working fluids. However, cavitation characteristics differ considerably with the working fluids. Recent patents filed/published in this area revealed that efforts are needed to develop effective cavitationresistant centrifugal impellers and pumps.

Investigation of efficiency models in EnergyPlus and AMCA standard 207 for induction motors powered by variable frequency drives

Variable frequency drives (VFDs) are widely applied on induction motors to reduce motor electrical power under partial load conditions by adjusting both the frequency and voltage. For centrifugal fan, pump and compressor applications, a squared voltage/frequency ratio voltage control results in better motor energy performance than a linear ratio control and is recommended by VFD manufacturers. The motor efficiency model in EnergyPlus is regressed based on manufacturer motor data without VFDs by ignoring the VFD impacts while the motor efficiency model in AMCA standard 207 adopts a linear ratio control rather than a squared ratio control, thus these two models do not reflect the actual motor operating conditions and the inaccurate motor efficiency data may be used in energy simulation. The paper is to investigate these two motor efficiency models using AHRI certified motor data and an experiment conducted on a VFD-motor-belt-fan system. The investigation results show both the EnergyPlus and AMCA models cannot accurately calculate motor efficiency controlled by the squared ratio with VFDs. The EnergyPlus model underestimates the VFD-motor-belt drive system efficiency by 10–25% while the AMCA model underestimates the VFD-motor-belt drive system efficiency by 5–10% in a frequency range between 30 and 40 Hz.

Optimization parameters of the heart pump design

In this paper, research of optimization parameters of continuous flow heart pump is presented. The application of centrifugal pumps as heart assist devices imposes design limitations on the geometry of the heart pump. Geometry and pump parameters affect the performance and the hemocompatibility of the heart pump. The main quality assessment factor for heart pump is the pump hemocompatibility i.e., the amount of mechanical damage caused by a pump on blood cells. Besides stagnation zones and recirculation zones, wall shear stress is parameter that is used to predict pump hemocompatibility. Second important factor is minimal volume of heart pump with acceptable anatomical fitting. Additional factors are high efficiency and durability. The aim of the research is to propose the optimal design of bladeless centrifugal heart pump. The dimensionless optimization parameters of the heart pump design are derived from Navier - Stokes equation. In conclusion, dimensionless optimization parameters of bladeless centrifugal continuous flow heart pump are presented.

A high-efficient centrifugal heat pump with industrial waste heat recovery for district heating

The urban construction area and heating energy consumption in northern China have been increasing greatly in recent years. At the same time, a large amount of low-grade industrial waste heat is released directly to the environment in most industrial plants. To meet the district heating demands and recover the industrial waste heat simultaneously, high-efficiency centrifugal heat pumps are applied for district heating and heat recovery. A permanent-magnetic synchronous frequency-convertible (PSF) centrifugal heat pump is developed which has a much higher COP in comparison with that of conventional heat pumps. In a district heating project with waste heat recovery from industry, testing results have shown that COP of a 500RT PSF centrifugal heat pump could reach 7.1, and the total system COP of the district heating system reaches 4.8. The operating cost for one heating season is just 40.3% of gas-fired boiler heating system. The emission of Carbon Dioxide is reduced by 60.6% and 56.3% when compared with coal-fired boiler and gas-fired boiler heating system, respectively. This shows that application of PSF centrifugal heat pumps to recover the low-grade industrial waste heat for district heating are quite attractive in the north of China cities.

Modelling and development of a vibration-based electromagnetic energy harvester for industrial centrifugal pump application

This paper reports a unique vibration-based electromagnetic energy harvester (VEH) designed to power wireless sensors used for fault monitoring of industrial centrifugal pumps. The design consists of two independent moving parts; the central part and the outer part. The uniqueness of the VEH design exists in its ability to produce higher relative velocity between its two moving parts by isolating vibration from the outer part. The developed prototype produced an open-loop voltage of 3.48V and a closed-loop voltage of 1.63V for an optimum load of 700Ω. This constituted for an average power of 3.8mW delivered to the load at a natural frequency of 200Hz and an excitation level of 1g. The experimentation results were in good agreement with the simulation results as the average percentage error was within an acceptable range of 6.15%. A case study is also presented whereby a ZigBee transceiver is successfully powered from the output generated by the VEH.

The Effect of Geometry on the Efficiency and Hemolysis of Centrifugal Implantable Blood Pumps.

The application of centrifugal pumps as heart assist devices imposes design limitations on the impeller geometry. Geometry and operating parameters will affect the performance and the hemocompatibility of the device. Among all the parameters affecting the hemocompatibility, pressure, rotational speed, blade numbers, angle, and width have significant impact on the blood trauma. These parameters directly (pressure, speed) and indirectly (geometry) affect the efficiency of the pump as well. This study describes the experimental investigation on geometric parameters and their effect on the performance of small centrifugal pumps suitable for Mechanical Circulatory Support (MCS) devices. Experimental and numerical techniques were implemented to analyze the performance of 15 centrifugal impellers with different characteristics. The effect of each parameter on the pump performance and hemolysis was studied by calculating the normalized index of hemolysis (NIH) and the shear stress induced in each pump. The results show five and six blades, 15-35° outlet angle, and the lowest outlet width that meets the required pressure rise are optimum values for an efficient hemocompatible pump.

Numerical Simulation on End Suction Centrifugal Pump Running in Inverse Flow for Microhydro Applications

The initial capital cost for most microhydro projects has always been an overriding issue for self-funded remote communities. The cost will escalate significantly in the absence of local microhydro electromechanical manufacturers. The application of end suction centrifugal pump as turbine will reduce the overall cost, which renders microhydro systems feasible for self-funded projects and are therefore suitable for rural communities. The goal of this study is to design and develop a pump as turbine (PAT) which serves as a substitute to commercial electromechanical components. Numerical analysis of an inverse flow for an end suction centrifugal pump is presented in this paper, which includes the performance curves and hydraulic characteristics of the pump. ANSYS CFX, a commercial CFD software is used to simulate the performance of the pump with specific speed, Ns of 70 units (Euroflo EU50-20). The computational flow domain inside the pump is comprises of impeller, volute and draft tube. Unstructured tetrahedral mesh is used to maintain good surface mesh due to complex flow domain geometries. The governing equations used in the simulations are three-dimensional, incompressible Navier-Stokes and k-ϵ turbulence model under steady-state condition. The simulation results are compared with pump performance curve supplied by the pump manufacturer. The verification results show good agreement for flow rates between 0.7 and 1.3 QBEP. The best efficient point (BEP) for inverse flow is attained at a higher head and flow rate compared to pump mode, whereby the value is found to be 21.55 m and 14.0 l/s, respectively. It is believed that the findings of this study will be useful to predict hydraulic characteristics and performance curves of PAT and the model may be used to identify poor flow characteristics inside the pump. It is recommended that optimization process is carried out using CFD tools in future studies.

Suspension Performance of a Two-Axis Actively Regulated Consequent-Pole Bearingless Motor

The objective of this study is to investigate the suspension performance of a proposed two-axis actively regulated consequent-pole bearingless motor with C-shaped segmented cores. The motor is intended for use in compact, contamination-free centrifugal pumps. In this bearingless motor, the two-axis radial motion of the rotor is actively regulated. Additionally, the axial and tilting motions of the rotor are passively stabilized. In addition, rotating angle detection is not required for active magnetic suspension, unlike conventional permanent-magnet-type bearingless motors. The test machine is stably driven without any mechanical contact at a rated speed of 3000 r/min. The rotor vibration in the actively and passively regulated directions is less than 1/10th of the range of rotor motion. The test results demonstrate the feasibility of the proposed bearingless motor for centrifugal pump applications.

Comparison of some laboratory wear tests and field wear in slurry pumps

A number of different laboratory wear tests have been undertaken to measure the wear resistance of a natural rubber and a eutectic and hypereutectic white iron under abrasion and erosion conditions. Laboratory work included two different slurry jet erosion tests, a Coriolis test and an ASTM dry sand rubber wheel test.The laboratory results were compared with wear of the same materials in a centrifugal slurry pump application in a mineral processing plant. The pump application has been monitored for over 2 years and over 40 parts run to destruction. Analysis of the wear data shows a factor of almost 3 difference in wear rate between the rubber and the best white iron. Coefficient of variance of the data was in line with typical wear results from the field.The laboratory wear tests were conducted with a silica sand slurry and average particle size range of 300–500μm to match the field conditions. The Coriolis and one of the jet erosion tests showed order of magnitude similarity with the field test results for the metals, but the other tests gave very different trends. The jet and Coriolis erosion tests on the rubber showed a much lower wear rate than seen in the field, while the DSRW test found that the eutectic white iron wear rate was lower than that of the hypereutectic iron (all opposite of the field test).Explanation for the different wear rates between the laboratory and field tests was postulated to be non-representative wear mechanisms. This is compounded by the lack of understanding of specific wear conditions in the pump (local velocity, concentration, particle size, size distribution and particle shape) as well as microstructure of the samples.

The Use of Steady Multi-Phase Position and Unsteady Computational Methods in the Numerical Simulation of Double-Suction Centrifugal Pump

In order to compare the steady multi-phase and unsteady calculation in double-suction centrifugal pump application, this article simulates the internal turbulent flow of the 150S-50 double suction centrifugal pump. Numerical simulation uses realizable turbulence model, simulating with two methods of steady multi-phase and unsteady in 7 cases. Based on the numerical simulation, the head, shaft power, efficiency were calculated, the simulated performance curves of a double suction centrifugal pump is processed. The results show that: The results of unsteady simulation are closer with the experimental data.

Evaluation of a Bearingless PM Motor With Wide Magnetic Gaps

A new noncontact drive system has been developed employing a consequent-pole-type bearingless permanent magnet (PM) motor and a thrust magnetic bearing. This bearingless motor has a wide magnetic gap. The wide magnetic gap may cause a decrease in radial magnetic suspension force because of an increase in magnetic reluctance. A thrust magnetic bearing is installed at the end of the shaft because strong thrust force exists in centrifugal pump applications. In this paper, the magnetic suspension forces and rotation characteristics of the experimental prototype are evaluated while the rotor is magnetically suspended. Experimental results are also compared to the calculated ones using the finite-element method. It is demonstrated that the developed consequent-pole-type bearingless PM motor possesses sufficient magnetic suspension force for noncontact operation.

Model based fault detection in a centrifugal pump application

A model based approach for fault detection in a centrifugal pump, driven by an induction motor, is proposed in this paper. The fault detection algorithm is derived using a combination of structural analysis, observer design and Analytical Redundancy Relation (ARR) design. Structural considerations on the system is used to divide it into two cascaded connected subsystems, giving an example on using a general structural approach to divide a complex problem into a set of less complex and solvable problems. The variables connecting the two subsystems are observed using an adaptive observer derived on the basis of the equations describing the first subsystem. No faults are expected to affect the first subsystem, therefore only the second subsystem is considered in the design of the fault detection algorithm. The fault detection algorithm is based on an ARR, which is designed using structural analysis and the Groebner basis algorithm. The polynomial form of the obtained ARR is utilized to achieve robustness w.r.t. parameter variations by using a set-valued approach. The applicability of the algorithm is illustrated by applying it to an industrial benchmark. The benchmark tests have shown that the algorithm is capable of detecting four different faults in the mechanical and hydraulic parts of the pump.

HYDRAULIC SUSPENSION GYRO PUMP

An impeller suspension mechanism is a major concern to avoid thrombus formation for long-term centrifugal pump application. A gyro-type centrifugal pump has been developed as permanent implantable ventricular assist device (VAD). Currently, this titanium-made gyro pump utilizes a novel hydraulic impeller suspension system. This study aims to evaluate the anti-thrombogenicity of the hydraulic suspension (HS) gyro pump. In vitro studies were conducted to examine the platelet adhesion at the bottom pivot, which is a primary lesion of white thrombus after pump implantation. For the pump hemorheology analysis, the particle tracing flow visualization was performed utilizing. In addition to these in vitro studies, current in-vivo animal studies were retrospectively examined.TableHS pumps demonstrated 50% lower platelet adhesion rate at the bottom pivot lesion compared to the control gyro pump. With the flow visualization study, continuous washout flow was created around the the center pivot behind the impeller. Total 20 pumps were implanted to 10 calves, and no thromboembolism was observed. Only one case had thrombus formation inside the right pump head due to low pump flow caused by the outflow graft kinking. This HS gyro pump is a compact, secure, and affordable VAD.