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Multistage pumps are intended to improve designs with low-vibration and -noise features as the industry applications increase the technical requirements. In this frame, it becomes really important to fully understand the vibration patterns of these kinds of complex machines. In this study, a vibration test bench was established to examine the vibra...
Citations
... The feature selection for MPL-ANNs are crucial to developing an effective regression model. Mechanical vibration demonstrates a high correlation with changes in pressure fluctuations [10], flow rate increase [13], out-design operational points [11], and change in fluid properties [4].This study introduces a MLP-ANN framework with RMS extraction from different mechanical vibration frequency bands and hyperparameters optimization throughout The Tree-structured Parzen Estimator (TPE) algorithm [14]. ...
... Regarding the research on pump vibration, Luo et al. 14 proposed that the abnormal vibration frequencies caused by backflow and rotational stall are mainly concentrated in the low-frequency band, approximately 0.23-0.25 times the rotational frequency. Bai et al. 15 established that flow rate significantly affects pump inlet and outlet vibration, with main vibration frequencies ranging from one to four times the blade passing frequency (BPF). Khalifa et al. 16 found a strong correlation between vibration and the pressure pulsation behavior of the pump, particularly at high speeds and offdesign flow rates, which excite stronger vibrations. ...
When a vessel reaches a specific speed, the circulating pump in the cooling system stops driving. It relies only on the kinetic energy its speed generates to provide cooling seawater for the condenser. This cooling strategy is known as natural flow cooling. Under natural flow conditions, the impeller rotates passively due to flow impact, and the circulating pump serves as a significant resistance component in the cooling system. The unstable flow within a pump is primarily attributed to the varying scales of stall vortex, which can induce vibration and potentially result in severe damage to components. To investigate the generation of stall vortex and vibration characteristics under natural flow conditions, the numerical simulation method was employed to study the structure and motion characteristics of stall vortex in multi-stage pumps at different flow rates. Moreover, vibration signals were collected through a natural flow experiment, and the obtained data were analyzed using empirical mode decomposition with singular value decomposition and wavelet transform methods. The result indicates that natural flow conditions can be categorized into impeller stuck and passive rotation. During passive rotation, the speed increases linearly with the flow rate. Thus, the blade inlet's attack angle remains consistent at different flow rates, making the internal flow features similar. The stretching and bending of the stall vortex structure primarily cause the variation of the vorticity. Additionally, the internal structure and motion pattern of stall vortex exhibit similarities. The excitation force increases continuously with the flow rate and is related to the effects of flow losses and turbulent kinetic energy. Vibration energy caused by stall vortex and rotor–stator interference is mainly concentrated in the low-frequency band.
... As mentioned by [2], "knowledge of distinguishing fault is ambiguous because definite relationships between symptoms and fault types cannot be easily identified". Alterations in pressure, flow rate, and elevation are normally detected by dedicated software through spectral analysis [3][4][5], but the type of mechanical fault that originally provoked the identified failure normally remains obscure [2]. ...
... Two pumps with 4 and 6 stages were used exclusively to provide data for healthy conditions. We recall that most previous experimental works consider single stage pumps of one particular model (see, e.g., [2][3][4][5][10][11][12][13][14]). ...
... Bai et al. [4] assembled a vibration test bench to examine the vibration and stability of a cantilever multistage centrifugal pump under different flow conditions. Vibration was observed to depend on mass unbalance at the shut-off flow rate point. ...
The present work assesses the feasibility of using vibration signals to establish correlations between different types of faults (a state) and related failure modes (an event) in electric submersible pumps (ESPs). Most available diagnosis software strives to distinguish between normal and abnormal conditions in centrifugal pumps, but are not capable of directly correlating a detected type of failure to an existing mechanical fault. Here, several types of controlled mechanical faults are applied to seven different ESPs as a means to try to correlate via spectrum analysis typical signatures to given fault-failure pairs. Pressure and flow rate data together with vibration signals were collected to detect the wear state and operational conditions of known pumps. The acceleration data were analyzed using Spectral Analysis and Power Spectral Density techniques. This paper introduces an approach based on Random Forests, an algorithm that uses decision trees for classification and regression. The work shows that the proposed procedure is accurate and general enough to allow fault-failure identification and classification.
... When the flow rate of the booster pump 2 increases in range of 50 to 90%, by opening CV, the flow rate in the pump stabilizes and the vibration intensity of the impeller decreases. The analysis shows that at small flow rates, the flow in the booster pump is very unstable, with significant backflow and strong local abrasion, and as the particle concentration increases, the flow resistance increases [12]. With the increase of flow through another opening of CV from 50 to 90%, the flow in the pump tends to be stable, and the increase of flow causes the vibration of the whole centrifugal pump to change in a small range. ...
PurposeVibration monitoring is being utilizing for decades to determine the condition monitoring of the various rotating systems and Plasma Facing Components (PFCs) during operation. With this aim, a vibration diagnostics along with LabVIEW program for vibration analysis is being setup at the High Temperature Technologies Division (HTTD) of IPR for condition monitoring.Method
Vibration diagnostics consists of an accelerometer, signal conditioning unit, NI PXI based acquisition card and LabVIEW code (developed in-house) to analyze the results in terms of acceleration, Root Mean Square (RMS) and frequency spectrum analysis.ResultsThe results of condition monitoring using developed vibration diagnostics provides heath of the rotating components and PFCs in High Heat Flux Test Facility (HHFTF).Conclusion
To summarize, the development of vibration monitoring diagnostics and its results on application for condition monitoring of (1) rotating systems such as Vacuum Systems (VS), High Pressure High Temperature Water Circulation System (HPHT-WCS) and (2) PFCs during the Critical Heat Flux (CHF) test in HHFTF are demonstrated.
... The direct correlation between vibration and the pump's operating state has also been extensively observed and studied, providing a foundation for further research in state detection and classification [18]. Ling et al. have proven that the combination of Internet of Things (IoT) technology and advanced machine learning methods offers cost-effective and user-friendly tools for condition monitoring in irrigation pump operation with high reliability [19]. Previous studies have also explored the use of artificial intelligence (AI) in preventive maintenance, utilizing techniques such as support vector machine (SVM) algorithms for vibration-based pump failure detection [20,21]. ...
... Digital Twins and simulation models Accurately predict the operating state of a centrifugal pump through simulation models [4,7] Sensor-less Detection Utilizing deviations in motor electrical signals to detect cavitation [5] Vibration Analysis Monitoring vibrations caused by cavitation-induced instabilities [18][19][20][21][22] Acoustic Emission Analysis Detecting acoustic signals generated during cavitation events [13][14][15][16][17] Flow Visualization Close-up imaging of cavitation formation to study impeller geometry and cavitation magnitude [8] Computation Fluid Dynamics (CFD) Analyzing vibration and sound data for various types of compressors, including pumps and fans [9] Artificial Neural Networks (ANN) Utilizing neural networks for signal and image analysis to detect operating conditions [10,[19][20][21] Convolutional Neural Networks (CNN) Employing CNN models for diagnosing deviations in pump operation and piping leakage using acoustic data [11,16,17] The scope of this study was to assess and compare four standard classification methods using raw signals from a low-cost data acquisition platform, ultimately identifying a simple yet highly reliable algorithm for detecting cavitation. By using signal and vibration data with minimum processing (no feature extraction) and leveraging machine learning and deep learning techniques, the research explored their effectiveness in fault detection and condition monitoring of centrifugal pumps, providing invaluable insights for future advancements in IoT-integrated real-time fault detection and operation monitoring applications. ...
... Digital Twins and simulation models Accurately predict the operating state of a centrifugal pump through simulation models [4,7] Sensor-less Detection Utilizing deviations in motor electrical signals to detect cavitation [5] Vibration Analysis Monitoring vibrations caused by cavitation-induced instabilities [18][19][20][21][22] Acoustic Emission Analysis Detecting acoustic signals generated during cavitation events [13][14][15][16][17] Flow Visualization Close-up imaging of cavitation formation to study impeller geometry and cavitation magnitude [8] Computation Fluid Dynamics (CFD) Analyzing vibration and sound data for various types of compressors, including pumps and fans [9] Artificial Neural Networks (ANN) Utilizing neural networks for signal and image analysis to detect operating conditions [10,[19][20][21] Convolutional Neural Networks (CNN) Employing CNN models for diagnosing deviations in pump operation and piping leakage using acoustic data [11,16,17] The scope of this study was to assess and compare four standard classification methods using raw signals from a low-cost data acquisition platform, ultimately identifying a simple yet highly reliable algorithm for detecting cavitation. By using signal and vibration data with minimum processing (no feature extraction) and leveraging machine learning and deep learning techniques, the research explored their effectiveness in fault detection and condition monitoring of centrifugal pumps, providing invaluable insights for future advancements in IoT-integrated real-time fault detection and operation monitoring applications. ...
The scope of this study is the evaluation of early detection methods for cavitation phenomena in centrifugal irrigation pumps by analyzing the produced vibration and sound signals from a low-cost sensor and data acquisition system and comparing several computational methods. Vibration data was acquired using the embedded accelerometer sensor of a smartphone device. Sound signals were obtained using the embedded microphone of the same commercial smartphone. The analysis was based on comparing the signals in different operating conditions with reference to the best efficiency operating point of the pump. In the case of vibrations, data was acquired for all three directional axes. The signals were processed by computational methods to extract the relative features in the frequency domain and use them to train an artificial neural network to be able to identify the different pump operating conditions while the cavitation phenomenon evolves. Three different classification algorithms were used to examine the most preferable approach for classifying data, namely the Classification Tree, the K-Nearest Neighbor, and the Support Vector Data algorithms. In addition, a convolutional neural network was utilized to examine the success rate of the classification when the datasets were formed as spectrograms instead. A detailed comparison of the classification algorithms and different axes was conducted. Comparing the results of the different methods for vibration and sound datasets, classification accuracy showed that in the case of vibration, the detection of cavitation in real conditions is possible, while it proves more challenging to identify cavitation conditions using sound data obtained with low-cost commercial sensors.
... As a high-speed rotating machine, the influence of vibration cannot be neglected. A lot of research has been done on the inducing factors of centrifugal pump vibration, and the main influencing factors are divided into two categories: mechanical structure and fluid excitation [1,2,3]. ...
... When conducting the electric auxiliary machine test, the main steps include the following: (1) We disconnect the circuits, install the electric auxiliary machine on the test bench, check whether the four bracket bolts and vibration-damping rubber pads are loose, and check whether the power supply line is normal. (2) We have access to power for the auxiliary power test; if the equipment runs smoothly without noise, then through the installation and commissioning, we disconnect the power. (3) In the electric auxiliary machine bracket of four corner positions, we install acceleration sensors, arrange the signal acquisition system, and debug the upper computer. ...
... The model of multi-factor analysis of variance is a continuation of the general linear model. The generalized model is expressed as: (2) where is the total variation of the observed variable, and are the variations caused by the independent action of factor and factor , is the variation caused by the interaction of factor and factor , and is the variation caused by random factors. can be used as an indicator of the effect size of ANOVA [24]. ...
In some important equipment such as vessels, the requirements for vibration reduction and cost-effectiveness of centrifugal pumps are becoming more and more stringent. It becomes really essential to present a method to assign manufacturing accuracy for shaft system assembly considering vibration and cost. A numerical model of the pump shaft system is developed to analyze the residual unbalance of the pump shaft system. The finite element model was verified through prototype tests. A machining accuracy allocation scheme is proposed by using an orthogonal design, and the cost and vibration intensity of the shaft system generated by vibration are evaluated. Based on this, a method to distribute shaft system machining accuracy is proposed to control the cost as much as possible while ensuring the vibration. Through orthogonal design, multiple sets of key parameter combinations are obtained, the vibration response of the shaft system under the parameter combination is calculated, and the contribution of each shaft system error to the shaft frequency vibration is analyzed. Combining the relative machining cost of the shaft system under different parameter combinations, the optimal allocation of the key parameters of the shaft system is completed based on vibration evaluation and relative cost.
... They also noted that higher flow rates resulted in higher pressure fluctuations, which affect the pump's vibration. Similarly, Bai et al. [28] and Wang et al. [29] observed that the vibration amplitudes increased with the flow rate for a multistage centrifugal pump. Cui et al. [30] observed that the vibration energy decreases as the pump approaches its highest efficiency point. ...
Electric Submersible Pumps (ESPs) are multistage centrifugal pumps used in the artificial lift and transport of multiphase fluid mixtures. The flow regime is a liquid–liquid flow when the fluids correspond to two non-miscible fluids. Liquid–liquid flow is a mixture with a continuous and dispersed phase. As the amount of fluid in the dispersed phase increases, the dispersed phase suddenly becomes continuous and vice-versa. This transition phenomenon is called phase inversion. The flow regimes in oil–water mixtures are oil-in-water (o/w) and water-in-oil (w/o) flow regimes. This work demonstrates a correlation between the flow regime and the flow-induced vibration (FIV) in ESP operating with an oil–water mixture. This research proposes a novelty method to flow regime identification based on the Root Mean Square (RMS) of the vibration acceleration of the Fast Fourier Transform (FFT) signal.
The experimental setup consists of an 8-stage Electrical Submersible Pump (ESP) and a vibration acquisition system with six accelerometers uniformly distributed along the ESP. The experimental procedure consists of changing the water cut (percentage of water) from the oil flow regime to the water flow regime, maintaining stable ESP rotational speed, the total flow rate, and the oil viscosity. For each water cut, mechanical vibration is collected. The operational conditions consider 30, 40, and 50 Hz rotational speeds and viscosities between 70 and 210 cP.
Frequency domain analysis involves studying FFT between 0 and 5000 Hz, considering different water cuts and frequency ranges. Statistical features – mean, variance, geometric mean harmonic mean, and RMS – were extracted from the FFT for each frequency range. Results showed a strong correlation between the RMS of FFT and the phase inversion phenomena considering the rotational speed. A logistic regression model was employed to establish a transition boundary between oil-in-water and water-in-oil using 10% of the data. The model successfully separated at least 95.67% of the remaining data in the least favorable scenario.
... Under the same cavitation number, the sound power on the suction side of the blade is greater than that on the pressure side. With a decrease in cavitation number, the fluctuating radiation noise of the cavitation volume is the main noise source for the increased sound power [25][26][27][28][29][30]. ...
Low specific speed centrifugal pumps typically suffer from low efficiency and severe backflow; adding optimally structured splitter blades can play a role. In this paper, the distribution of pressure and velocity in the flow channel is analyzed using CFD simulation for a low specific speed centrifugal pump. The geometric parameters of the splitter blade are optimized using an orthogonal test and an artificial fish swarm algorithm; then the optimal splitter blade structure is obtained. Results showed that the splitter blade not only effectively solves the backflow of the flow channel and compresses the range of the trailing vortex, but it also alleviates the cavitation at the inlet of the main blade. When considering the best head, the order of influence of each factor is: Splitter blade thickness > Splitter blade inlet diameter > Splitter blade inlet width. At this time, the thickness of the splitter blade is 4.5 mm, splitter blade inlet diameter is 155 mm (0.775) and Splitter blade inlet width is 23 mm. Through the closed pump experimental system, it is confirmed that hydraulic performance has been improved.
... The centrifugal pump, which converts mechanical energy into kinetic and pressure energy when fluid rotates in an impeller, is one of the most popular and important fluidconveying equipment in the field of ocean engineering [1][2][3]. The impeller plays the most important role among all pump components [4]. ...
... Mansour et al. [15] used numerical calculations and a high-speed camera to compare the effects of a round BTE and trimmed BTE on the performance and flow regime of a single-phase and air-water two-phase flow in a centrifugal pump, showing that the round BTE provided better performance than the trimmed BTE in both the single and two-phase flow. According to the study by Huang et al. [1], cutting the BTE on the PS to reduce the outlet angle could increase the pump head and efficiency, reduce the velocity in the jet zone of the PS near the impeller outlet, improve the uniformity of the Euler head distribution, and reduce the intensity of pressure pulsation. Lin et al. [16] and Lin et al. [17] investigated the effect of a bionic sinusoidal trailing edge on the pressure pulsation and energy loss of a centrifugal pump, and their results showed that a reasonably designed bionic trailing edge can effectively reduce pressure pulsation and internal flow loss. ...
... There are a total of 16 BTE models, including the original one. As shown in Figure 1a, the 4th-order Bezier curve controlled by five points from P0-P4 is plotted by Equation (1). P0 is the intersection of the PS and the BTE, and P4 is the intersection of the SS and the BTE; they can move along the blade surface. ...
The centrifugal pump is one of the most widely used types of power machinery in the field of ship and ocean engineering, and the shape of the impeller blade trailing edge has an important influence on their performance. To reveal the mechanism of the effect of different trailing edges on external performance, the internal flow of 16 types of impeller blade trailing edges of a centrifugal pump, consisting of Bezier trailing edges, rounding on the pressure side, cutting on the suction side, and the original trailing edge is studied by numerical simulation. The reverse flow, shaft power, and energy loss distribution in the impeller and diffuser along the streamwise direction are analyzed by calculating them on each micro control body sliced from the fluid domain. The entropy production theory and Ω-vortex identification method are used to display the magnitude and location of energy loss and the vortex structure. Finally, a static structural analysis of the impeller with different trailing edges is performed. The results show that different impeller trailing edges can clearly affect the efficiency of the pump, i.e., the thinner the trailing edge, the higher the efficiency, with the thickest model reducing efficiency by 5.71% and the thinnest model increasing efficiency by 0.59% compared to the original one. Changing the shape of the impeller trailing edge has a great influence on the reverse flow, shaft power, and energy loss near the impeller trailing edge and diffuser inlet but has little influence on the leading part of the impeller. The distribution of local entropy production rate, energy loss, and reverse flow along the streamwise direction shows similar rules, with a local maximum near the leading edge of the impeller due to the impact effect, and a global maximum near the impeller trailing edge resulting from strong flow separation and high vortex strength due to the jet-wake flow. Thinning the impeller trailing edge and smoothing its connection with the blade can reduce the vortex strength and entropy production near the impeller trailing edge and diffuser inlet, improve the flow pattern, and reduce energy loss, thus improving the pump efficiency. In all models, the maximum equivalent stress is less than 6.5 MPa and the maximum total deformation is less than 0.065mm. The results are helpful for a deeper understanding of the complex flow mechanism of the centrifugal pump with different blade trailing edges.
... Zhang et al. and Zhang et al. proposed and optimized the equations and parameters of 3D blade formation [8,9]. Bai et al. built a vibration test stand to examine the vibration and stability of cantilever multistage centrifugal pumps at diferent fow rates [10]. Feng et al. studied the rotational stall characteristics inside the vane difuser of a centrifugal pump based on ANSYS CFX [11]. ...
Centrifugal pumps are widely used for the transport of fluids, but low-specific-speed centrifugal pumps widely have problems with serious backflow and low efficiency. In this paper, a low-specific-speed centrifugal pump with a specific speed of 55 is used as a research object. By combining numerical simulation and orthogonal experiment, the pressure distribution and velocity distribution of the flow channel are analyzed, the priority of each geometric factor for slits on pump performance is determined, the geometric parameter structure of the slotted blade is optimized by entropy weight on TOPSIS, the optimal impeller slit solution is obtained. The results show that with a balance of head and efficiency, the order of influence of the factors is: slit center width b > diameter of slit D > shrinkage ratio of slit f > depth of slit h > deflection angle of slit β . The optimal combination of slit geometry parameters is: slit center width is 3 m m , diameter of the slit is 200 m m , shrinkage ratio of the slit is 0.5, depth of the slit is 6 m m , and the deflection angle of the slit is 20°. Through ANSYS FLUENT simulation and experiment of closed pump experiment system, confirmed that hydraulic performance is improved.
