Single-stage Centrifugal Pump Research Articles

Prediction of Progressive Erosion Characteristics of Centrifugal Pump Blades Based on Dynamic Boundaries

Abstract The conventional method of fixed boundaries for predicting erosion inadequately reflects the erosion characteristics of centrifugal pumps under realistic operating conditions. In this research, we employ the dynamic boundary method, considering the influence of changes in wall morphology due to erosion on the flow field. We utilize the Euler-Lagrange approach and the E/CRC erosion model, incorporating a dynamic boundary geometry reconstruction strategy, to predict the erosion characteristics of the IS80-50-315 single-stage single-suction centrifugal pump. Solid-liquid two-phase flow calculations are conducted on the pump to predict erosion characteristics under varied operating conditions. The results show that the dynamic boundary-based progressive erosion prediction method realistically forecasts the erosion characteristics of the overflow wall and captures the evolution of blade morphology with erosion time. Erosion intensity on the blade suction surface significantly surpasses that on the pressure surface, guided by particle distribution characteristics in the centrifugal pump flow channel. Particle diameter primarily influences the erosion position of centrifugal pump blades; smaller particles induce erosion in the middle region of the blade, while an increase in particle diameter shifts the severe erosion position towards the impeller outlet direction. At a consistent particle diameter, higher particle concentrations correspond to elevated erosion rates in the blade area. We establish a relationship between the blade mass loss rate and erosion time during 2500 hours of pump operation at the design condition, introducing the blade mass loss rate for convenient assessment and prediction of blade damage in the centrifugal pump.

Performance Prediction of Centrifugal Norm Pumps Operating as Turbines

Pump-as-turbines (PAT) has been widely used during the last decade as one of the most interesting technologies in the field of energy recovery. Many studies and papers have been published in which the performance of the pumps in the turbine operating regime were analysed. Since horizontal single stage centrifugal norm pumps are most commonly used as PATs, their performances are analysed in this paper. Most of the research was related to individual pump aggregates or smaller groups and to obtaining their performance curves in turbine random mode. In this work, extensive experimental, numerical, and theoretical investigations were conducted to obtain complete dimensionless performance characteristics of single stage centrifugal norm pumps operating as turbines. One of the goals was to form a simple analytical expression that will, for this type of aggregate, map the pump operating characteristic to the appropriate turbine operating regime. By using the expressions obtained and presented in the paperwork, engineers are enabled to make the appropriate choice of pump aggregate for operation in turbine random mode for potential locations. For this purpose, the procedure for choosing the appropriate PAT aggregate or parallel operation of aggregates and the analysis of their operation on the existing system are presented in the paper. This innovative procedure allows us to select quickly PAT aggregates for a potential location and carry out appropriate techno-economic analyses and analyses of possible energy savings.

Analysis of axial force and pressure pulsation of centrifugal pump as turbine impeller based on dynamic mode decomposition

To investigate the spatiotemporal evolution mechanism of the axial force on a centrifugal pump acting as a turbine, this study focuses on a single-stage single-suction centrifugal pump and applies dynamic mode decomposition (DMD) to decompose the flow field of the turbine impeller's axial force. The axial force of the impeller under three flow conditions, namely, 1.0Qd, 1.3Qd, and 1.6Qd, is extracted and analyzed. Results show that the DMD method can accurately extract the spatiotemporal coherent structural characteristics of the main modes of axial force, with the first five modes accounting for more than 99.97% of the total mode energy. Under the 1.3Qd condition, the flow field is stable, and the axial force remains constant over time with a very small degree of pressure pulsation. However, under the 1.6Qd condition, the flow field inside the pump becomes complex and unstable, leading to larger changes in axial force compared to the 1.0Qd condition, with an increase in 2.13 times. The amplitude of the pressure pulsation gradually decreases from the impeller inlet to the outlet under both 1.0Qd and 1.6Qd conditions, with vibration caused by the axial force mainly occurring at the impeller inlet. These findings provide a reference basis for improving the stability of centrifugal pumps acting as turbines.

Numerical and Experimental Investigations on the Acoustic Characteristics of a Single-Stage Centrifugal Pump

The acoustic properties of a single-stage centrifugal pump with low specific speed are investigated by means of compressible 3D CFD simulations (URANS) and experiments. In order to determine the pump’s acoustic transmission and excitation characteristics, a four-pole approach in the frequency domain is used. The transmission parameters determined by simulation are compared to experiments in water and air as functions of the Helmholtz number. The results indicate that the acoustic transmission characteristics within the experiments are significantly influenced by the structural compliance of the volute casing in terms of a fluid–structure interaction (FSI). A modelling approach for a one-dimensional representation of the centrifugal pump’s acoustic transmission characteristics in the time and frequency domains is applied to the current pump. As one model parameter, the effective speed of sound in the 1D model needs to be reduced to 607 ms−1 to account for the FSI. The agreement of the simulation results and the experiments underlines the above statement about the influence of the FSI. In a last step, the acoustic excitation parameter, depicted as monopole and dipole amplitudes, at two different blade-passing frequencies (fBP≈[111;169] Hz) are determined for several operating points. Especially for dipole amplitudes, a good agreement between experiments and simulations can be seen. The monopole amplitudes are also of similar orders of magnitude, but show stronger deviations. The cause of discrepancies between the 3D CFD simulations and experiments is believed to be the neglected influence of the FSI and surface roughness as well as the inaccurate reproduction of flow separation at the volute’s tongue due to the use of wall functions. A final important observation made during the numerical investigations is that the excitation mechanisms at the blade-passing frequency are probably independent of the piping system’s acoustic impedance.

Exploring a new criterion to determine the onset of cavitation in centrifugal pumps from energy-saving standpoint; experimental and numerical investigation

This paper proposes a new criterion to determine the cavitation initiation in centrifugal pumps. Because of the importance of saving energy, and the need for specifying a margin for the required net positive suction head (NPSHr) in all centrifugal pumps, a new criterion based on dropping three percent in efficiency (NPSHr,η) was investigated. Extensive experimental and numerical studies were undertaken to assess the effectiveness of the novel criterion from the energy-saving standpoint and its margin compared to the conventional one (NPSHr,Ht). A test bench was employed to conduct numerous experiments on five single-stage centrifugal pumps, generating comprehensive head-drop and efficiency-drop curves under part-load, designed, and over-load conditions. Additionally, simulations were carried out using CFD, employing an appropriate turbulence model and the ZGB cavitation model. Subsequently, dropping curves of total head, hydraulic efficiency, and the torque-rise curve against available NPSH were extracted. Analysis of these simulations revealed that NPSHr,η is consistently higher than NPSHr,Ht. A three-percent total head-drop diminishes the efficiency by an average of 6.04%, ranging from 4.79% to 8.92% depending on the specific case. Using NPSHr,η provides enough distance from the NPSHr,Ht without any need to specify a margin, and a huge amount of energy can be saved annually.

Cavitation diagnosis method of centrifugal pump based on characteristic frequency and kurtosis

Centrifugal pumps are important equipment in industrial production. At present, vibration signals are often used to diagnose cavitation in centrifugal pumps, but the vibration signals are easy to be disturbed and the fault characteristics are unstable to be detected. In this paper, a single stage centrifugal pump is taken as the study object, and the vibration signals of various parts of the centrifugal pump cavitation state are collected under different flow conditions. The short-time Fourier transform and one-third octave analysis are performed on the filtered signals, and the characteristic frequency of cavitation and the energy near the characteristic frequency with the development of cavitation are obtained. Based on vibration signals, the vibration root mean square (rms) and kurtosis values of different cavitation states are obtained. Flow state, kurtosis, and rms are used as input variables in the double-layer backpropagation neural network model to identify and classify the cavitation states of centrifugal pumps. The results show that the trained neural network model can accurately identify and classify the cavitation state of the centrifugal pump under the conditions of low flow rate, rated flow rate, and large flow rate, and the accuracy is more than 99.5%. This study provides a new technique for diagnosing cavitation in centrifugal pumps.

Influence of bionic structure on hydraulic performance and drag reduction effect of a centrifugal pump

Based on bionic theory, miniature dimple-type structures are constructed on the blades of a single-stage centrifugal pump to investigate the influence of the bionic structures on the hydraulic performance and drag reduction effect of the pump. The results show that dimples with shallower depth and which are located near the front section of the blade suction surfaces are more effective in improving the efficiency and reducing the drag of the pump. At small flow rate, due to the mismatch between the incoming flow angle and the blade placement angle, serious flow separation occurs in several flow channels, accompanied by the formation of the vortices, which would deteriorate the performance of the pump. With the arrangement of the dimples on blade suction surfaces, some low-speed vortices formed in the dimples, which is equivalent to increasing the effective thickness of the viscous substrate layer and decreasing the velocity gradient of the boundary layer. Therefore, the velocity distribution in the flow channels gets more uniform, and the turbulence kinetic energy and wall shear stress are thereby reduced.

Модель информационно-измерительной системы контроля центробежного грузового насоса на танкере-химовозе типа «Иван Поддубный»

On chemical tankers, the main cargo devices are pumps, so it is necessary to constantly monitor their operating conditions and performance indicators during operation. The article discusses modeling using MATLAB/Simulink software of a single-stage horizontal centrifugal pump, which can be used to create an information-measuring system for monitoring the performance of cargo pumps using the example of a chemical tanker of the Ivan Poddubny type. An analysis of the modeling results is carried out, including an assessment of pump efficiency, pressure loss and other indicators in various operating modes. The results allow us to draw conclusions about the operation of the pump under various loads and variable conditions. The simulated pump worked with seven different liquids pumped in chemical tankers: ethyl alcohol, N-propyl alcohol, phenol, chloroform, castor oil, 55% nitric acid and water. After this, a neural network was created using the MATLAB/Neural Network Fitting Tool application. The input data of the network were volumetric flow, pressure, shaft power, torque and suction pressure. The output value was the pump efficiency, the value of which was estimated for each fluid. The root mean square error of approximation was very close to zero. According to these results, the artificial neural network showed satisfactory results for predicting the efficiency of the centrifugal cargo pump of the Ivan Poddubny type chemical tanker; therefore, it can be used in ship information and measurement systems. Overall, this paper represents a valuable research contribution to the field of modeling horizontal centrifugal pumps using Simulink that can be useful to engineers and researchers involved in the design and optimization of these pumps.

Study on Performance Characteristics and Influencing Factors of Four-outlet Centrifugal Pump

In order to study the influence of different geometric parameters and performance parameters on the external characteristics and outlet head uniformity of a single-stage multi-outlet centrifugal pump, a certain single-stage four-outlet water pump was chosen as the research object. Under the premise of keeping all parameters except the target parameter constant, the number of impeller blades, outlet width, and mass flow rate at the outlet were studied separately to explore the variation trends of the average pressure fluctuation rate and average head when the number of blades changed from 5 to 8. The study was combined with numerical simulation calculations. The research showed that as the number of blades increased, the head of the centrifugal pump gradually increased. When the number of blades was between 5 and 7, the increase in head was more significant, with an increase of 0.61m. When the number of blades increased to 8, the increase in head became relatively gentle, with only a 0.17m increase. When the impeller blades increased from 5 to 6, the pressure fluctuation rate at the outlet decreased by 0.4%. When the number of blades increased to 7, the pressure fluctuation rate decreased by 1.85%. When the number of blades increased to 8, the pressure fluctuation rate decreased by 0.8%. When the outlet width changed from 5.2mm to 6.7mm, the head increased by 0.4m, with an increase of 6.4%, and the pressure fluctuation rate at the outlet decreased by 2.9%. As the outlet flow rate increased from 15L/min to 30L/min, the head of the centrifugal pump decreased by 1m, and the pressure fluctuation rate at the outlet increased by 3.4%, indicating an increasing difference in head among the outlets.

Impact characteristics and erosion mechanism of solid particles in a centrifugal pump

To study the impact and erosion mechanism of solid particles in centrifugal pumps, the standard k–ε turbulence model and SIMPLE algorithm are adopted in this paper. Based on the discrete phase model (DPM) of the Lagrange method and McLaury erosion model, the flow impact characteristics and erosion mechanism of solid particles impacting the surface of flow passage components in a single-stage centrifugal pump were numerically simulated, and the test data were compared with the numerical simulation results of the external characteristics of the pump in clean water. The results show that the erosion mechanism of the pressure surface of the blade is mostly the impact erosion caused by high-speed particles with large impact angles, and the impact angle and impact velocity are larger near the tail of the pressure surface. The impact angle of solid particles on the shroud and hub is relatively small, but the erosion mechanism is still impact erosion. The erosion mechanism of the volute wall is mostly the cutting friction erosion caused by the low-velocity particles with small impact angles, and it is only impacted by the particles with large angles near the volute tongue, which is impact erosion. Overall, the average impact angle and impact velocity of the particles on the pressure surface of the blade are higher than those on the volute, so the erosion of the pressure surface is more serious than that of the volute in theory. The research results have certain theoretical reference value for improving the wear resistance of a centrifugal pump.

Effects of unstable flow structures on energy transfer mechanism in a centrifugal pump

To reveal the energy loss mechanism of the centrifugal pump, numerical simulation and experimental investigation are conducted to obtain the complex flow field of a single-stage centrifugal pump under various flow conditions. Particular emphasis is focused on the qualitative and quantitative analysis of the distribution and variation characteristics of irreversible loss in the pump model. The results show that the energy loss in the centrifugal pump mainly originates from the entropy generation caused by the turbulent dissipation and wall friction, which are typically generated in the volute and impeller domains. It is worth noticing that the energy loss in the volute is closely associated with non-uniform velocity distribution and the evolution of the shedding vortices from the impeller exit whilst the energy loss in the impeller are greatly affected by unstable flow phenomena such as flow separation, backflow, and jet-wake pattern. At the overload operating conditions, the wall entropy generation possesses a substantial influence on energy loss, which is mainly related to the wall shear stress. Meanwhile, the influence of the rotor-stator interaction and inflow impacting on the energy loss is enhanced with increasing flows. Finally, the omega method captured the vorticity structures near the tongue at partial flow conditions, thereby, revealing the relationship between the high magnitude of flow loss and the evolution of different scales of strong vorticity sheets.

Design, computational and experimental investigation of a small-scale turbopump for organic Rankine cycle systems

The hydraulic design, computational analysis, and experimental investigations of a high-speed small-scale turbopump for mobile waste heat recovery applications based on organic Rankine cycle systems are presented in this paper. Such applications demand high-pressure rise, lightweight, and compact pumping systems with simple construction. The investigated turbopump features an unshrouded 37.75 mm tip diameter single-stage centrifugal pump equipped with eight radial blades, eight splitters blades, and a rectangular axisymmetric volute. The pump should deliver 0.28 kg/s of mass flow rate with a pressure rise of 20 bar at a designed rotational speed of 25,000 rpm. Due to uncertainties observed in employing state-of-the-art 1-d methods that are valid for much larger machines, computational fluid dynamics is utilized to obtain a design meeting the specifications. The pump’s performance is evaluated experimentally at different rotational speeds, mass flow rates, and impeller tip clearances. The excellent agreement between experimental data and predictions from computational fluid dynamics validates the design methodology and computational results. The turbopump’s characteristics are then utilized to estimate the possible performance improvement of a target organic Rankine cycle using the novel turbopump instead of a commercial multi-stage centrifugal pump. The comparison suggests that the novel turbopump increases the efficiency of the target organic Rankine cycle by 0.3 % points and decreases its back-work ratio by nearly 50 %. The novel turbopump is approximately ten times more compact compared to commercial systems.

Analysis and Research on Vibration Characteristics of Nuclear Centrifugal Pumps Rotor Rubbing Fault

To investigate the vibration characteristics of nuclear centrifugal pumps rotor rubbing fault, the mechanical model of rotor rub is established, and the causes, types, and mechanisms of rotor rub fault are introduced. Taking the HAZ50-250 Type Horizontal single-stage centrifugal pump prototype as the object, through a reasonable test scheme, the vibration test and analysis of the rotor under different rub conditions were carried out using the Enpac2500 Dual channel spectrum analyzer, and the fault data of different rub impact degrees were collected. Combining the characteristics of vibration parameters such as time-domain, frequency-domain, and axis trajectory, it is found that the time-domain signal of rub fault shows an obvious “Top Clipping phenomenon.” The frequency-domain signal is mainly concentrated in one-time rotation frequency, two times rotation frequency, and a large number of nonlinear high harmonics. The axis trajectory will produce a concave image in the rub direction. In the actual rotor rub vibration fault diagnosis, it is necessary to comprehensively judge the vibration caused in combination with the operating state of the centrifugal pump, the state of the time domain, the frequency domain, and the axis trajectory. Based on the analyzed spectrum characteristics of the rub impact vibration, it is applied to the vibration fault diagnosis case of the centrifugal pump in the power plant, which timely prevents the pump damage and other faults caused by the deterioration of the rub impact fault, and plays a key role in the safe and stable operation of the centrifugal pump. It also provides an important reference for pump design and vibration fault diagnosis of rotating equipment in nuclear power plants.

Hydraulic optimization design of centrifugal pumps aiming at low vibration noise

In order to reduce the vibration noise generated by the centrifugal pump in the working process and improve the working efficiency of the centrifugal pump, the sound field numerical calculation of IS80-65-160 single-stage single-suction centrifugal pump was carried out. Under the condition that the parameters of the pump body and the impeller remain unchanged, the number of blades of the prototype pump impeller was designed as 4, 5, 6, and 7, respectively. The flow-induced vibration and noise characteristics of centrifugal pumps were studied from two aspects of numerical simulation and test, and the renormalization group k-ε model was used to simulate the steady and unsteady state of centrifugal pumps with different blade numbers. The external characteristics, pressure pulsation characteristics, vibration, and noise of the centrifugal pump were obtained, and the flow-induced vibration and noise test platform of the centrifugal pump was built for experimental verification. The research showed that the flow induction in the model pump was the main factor affecting the vibration of the prototype pump, and the shaft frequency and blade frequency were the main reasons causing the noise of the prototype pump. The vibration of each blade was the most concentrated at onefold blade frequency, and the peak of the sound field acoustic pressure level of the pump body was higher than other frequencies at threefold blade frequency, which was most obvious in the tongue region of the volute. With the increase of blades, the noise in volute decreased. The vibration intensity of the 4-blade prototype pump was lower, but the efficiency and head were also lower. The vibration intensity of the 5-blade prototype pump was the highest, the comprehensive performance of the 6-blade prototype pump was better, and the vibration of the 7-blade prototype pump was unstable. The test results showed that six blades could effectively reduce the flow-induced vibration noise of centrifugal pumps and improve the working environment, which provided certain application value and guiding significance for the hydraulic design of the subsequent low-noise centrifugal pumps.

Multiple Performance Optimization of a Single Stage Centrifugal Pump using an Intelligent System Approach

This study aims the use of an intelligent system to analyze and enhance the performance of a single stage centrifugal pump (SSCP) with respect to the blade number of impeller, which is crucial for the centrifugal pump design. In general, maximizing the efficiency (h) is the most common performance cost. Moreover, maximizing the pump head (H) and minimizing the power (P) are the other important criteria that should be considered for the optimal blade number. These goals are not simultaneously considered usually in the studies on this topic. The motivation of this study is to expand the system management perspective by evaluating the performance of the system with these multiple criteria. The centrifugal pump design is a typical Multi-Objective Optimization (MOO) problem. The MOO approach consists of five decision variables and three objective functions with different blade numbers for impellers. To determine the optimal solution of this MOO problem, the experimental data is initially expanded using a learning by examples methods based on an intelligent network model training. Then, extended data is used for calculating performance measures at each input-output pairs. In order to evaluate the results of the proposed approach on a real-time system, B50-200/100 type model pump with the speed of 2950 rpm and an outlet angle of 22.150 was tested at State Sugar Machine Plant, Eskisehir (Turkey). Since the main purpose is to determine the optimal blade number, different blade numbers has been used while other geometric parameters were kept constant. To determine the optimal solution, experimental data has used to train a selected soft computing model known as FWNN model. This model has advanced to express the relationship between the inlet and outlet values of the centrifugal pump. FWNN model achieves the general characteristics of the performance measure. The analysis with the use of FWNN model shows that, the optimum number of blades by considering the specified performance parameters for the centrifugal pump design is seven. Comparing with pump impeller with number of blades 5, 6, 8 and 9 increases in efficiency rates are 0.4%, 2.57%, 6.4% and 7.2%, respectively. The FWNN model over the performance analysis algorithm completes the missing data if exists and indicates the best performance solution as given.

Deneysel Tasarım Yöntemleri İle Bir Santrifüj Pompa Çarkında Dengeleme Deliği Tasarım Optimizasyonu

Bu çalışmanın amacı, rulmanlara gelen eksenel kuvvetleri azaltarak rulman ömrünü uzatmak için pompa çarkına açılacak en uygun dengeleme deliğinin belirlenmesidir. Çalışmada eksenel kuvvetlerin azaltılmasının yanı sıra pompa veriminde meydana gelen değişiklikler de dikkate alınmıştır. Bu çalışma için 1480 rpm hız, 350 m³/h debi ve 51 m basma yüksekliğine sahip tek kademeli santrifüj pompa seçilmiştir. Seçilen pompa çarkı üzerindeki dengeleme deliğinin tasarım optimizasyonu, deneysel tasarım metodu ve Hesaplamalı Akışkanlar Dinamiği (HAD) kullanılarak gerçekleştirilmiştir. HAD analizleri için Ansys Fluent programı kullanılmıştır. Optimum sonuca ulaşmak amacıyla dengeleme deliklerinin çark içerisindeki; delik merkezi açısı, delik çapı, delik merkezi çapı ve adedini belirleyen 4 parametre tespit edilmiş ve Çok Amaçlı Taguchi Yöntemi kullanılarak optimizasyon çalışması gerçekleştirilmiştir. Amaçlar; düşük eksenel yük ve yüksek pompa verimi olarak kabul edilmiştir. HAD sonuçları, varyans analizi (ANOVA) ve sinyal/gürültü (S/N) oranına göre değerlendirilmiştir. Yapılan çalışmalar sonucunda; delik çapının amaçlar üzerinde en etkili parametre olduğu tespit edilmiştir. Optimum tasarımın; belirlenen dört parametre için sırasıyla 0°, 12 mm, 100 mm ve 6 adet olduğu belirlenmiştir.

Effects of impeller geometry modification on performance of pump as turbine in the urban water distribution network

Nowadays, by increasing energy consumption, micro-scale energy production has received a lot of attention worldwide. Pressure control and electricity generation using existing hydraulic energy are possible by substituting the Soft Pressure Regulation System (SPRS) for a pressure reducing valves (PRV) in urban water distribution network (WDN) pipelines. The economical benefit and short start-up time are unique features of the SPRS that uses a pump as turbine (PAT). In this study, the numerical and experimental results of a single-stage centrifugal pump in direct and reverse working modes were compared and validated. The effect of passage width increasing, adding splitter blades and simultaneous modification of these parameters on improving the hydraulic performance of the PAT in the working range are investigated. Geometric modifications do not have the same effect on hydraulic parameters and efficiency in all operating ranges due to the significant range of flow rate variations in the WDN. Therefore, the statistical analysis was performed to identify the optimum modifications based on the PAT's working time in the specified flow rate ranges. The results show that simultaneous modification of parameters in the range of part-load condition (0.8QBEP) to over-load condition (1.2QBEP) reduces losses while increasing efficiency and power generation.

Investigation on the Influence of Entrained Air to Internal Flow of Centrifugal Pumps under Cavitation Condition

The introduction of air is often used in engineering to delay the occurrence of cavitation. A steady simulation on a single-stage and single-suction centrifugal pump was used to study the influence of the air on the internal flow under cavitation condition at 1% inlet void fraction. Steady simulation based on SST k-ω turbulence model and Rayleigh-Plesset cavitation model included in Ansys CFX 17.0 were processed to obtain vapor volume fraction, gas volume fraction and the turbulent energy of the impeller under the condition of natural cavitation and cavitation with entrained air. A homogeneous two-phase flow model was adopted to describe the air-water mixed flow. The experimental cavitation performance curve provides boundary condition support for the numerical simulation. In conclusion, it shows that the head of the pump keeps steady after 1% air entrained like natural cavitation. Then it goes worse when the cavitation number decreases but with lower NPSHr which means cavitation performance is improved by 1% air entrained. It indicated that the entrained air changes the distribution of the vapor in the passage of the impeller. However, the descent of the pressure over a certain value will also do harm to the internal flow of the model pump whether it is ventilating or not. The internal flow of the pump will be seriously damaged and even be blocked completely due to more and more vapor generated causing a dramatic decline of the head.

Analysis of Fluid-Structure Coupling Dynamic Characteristics of Centrifugal Pump Rotor System

Safety and reliable operation is one of the most important research areas for centrifugal pump systems, due to the interaction of complex flow, large structural load, and vibration caused by the operation of the impeller. To analyze the internal flow and impeller deformation of the centrifugal pump, the single-stage single-suction centrifugal pump titled IS100-80-160 was selected as the research object. Under the principle of single variable, the turbulent flow and structural response of three impellers designed by different parameters were calculated by CFX and ANSYS Workbench. A numerical simulation of steady flow at different flow rates of the centrifugal pump was carried out, and its hydraulic performance is consistent with the corresponding experimental results. By comparing the deformation of the impeller rotor system, it was found that the closed impeller has the worst stability with the best hydraulic performance; the impeller with split blades has the worst stability with the best hydraulic performance. This study could enhance the understanding of impeller FSI on centrifugal pump stability and provide a reference for improving the operational stability of centrifugal pumps.

Numerical and Experimental Research on the Influence of Clearance Between Impeller and Cover on the Pump Performance

Centrifugal pump is widely used and plays an important role in national economy. However, according to plenty of engineering practice and model tests, it indicated that the clearance between the impeller and pump cover is an important parameter for leakage loss and hydraulic efficiency. In this paper, a single stage centrifugal pump was selected to study the influence of clearance between impeller and pump cover on the hydraulic performance through combination of experiment and numerical simulation. Commercial software ANSYS CFX was employed to simulate the internal flow field with a clearance of 0 mm, and the experimental verification was carried out. The results presented that only a small difference was generated between experiment and numerical simulation, the maximum error is less than 4%, which can ensure the accuracy of the numerical calculation. At the same time, by comparing the simulation results with clearance of 0.1 mm, 0.22 mm, 0.42 mm and 0.62 mm, it found that with the increase of clearance, the impact loss at the tongue was significantly improved. In addition, with the increase of clearance, the effect of water flowing out from clearance interferes with the water at impeller inlet gradually improve. Finally, the hydraulic experiment with different clearance were carried out to verify the numerical result. Therefore, this research results have significant guiding effect for the design of clearance between impeller and cover in the future.