Pump Vibration Research Articles

Research on the Vibration Characteristic of a Seawater Hydraulic Piston Pump System and Vibration Reduction Approach

Seawater hydraulic piston pump has been widely used in ocean engineering and become a key power component for underwater equipment due to its inherent characteristic such as energy conservation and environment friendly. As one of the most important properties of seawater hydraulic piston pump, vibration would further determine the stability, reliability and stealth of underwater equipment. In this paper, the dynamic of a novel crankshaft seawater piston pump with gearbox are analyzed theoretically, illustrating the dramatically effect of the gearbox on the vibration characteristic of the seawater hydraulic piston pump. Then, a new type crankshaft seawater hydraulic piston pump system driven by a permanent magnet synchronous motor instead of asynchronies motor is proposed in order to eliminate the gearbox and improve the vibration characteristics. In addition, the vibration characteristic of this new type crankshaft seawater hydraulic piston pump system driven by asynchronous motor and permanent magnet synchronous motor are studied and compared experimentally. The experiment results indicate that the seawater hydraulic piston pump system driven by permanent magnet synchronous motor eliminating the gearbox has lower vibration acceleration level in comparison with the pump system driven by asynchronous motor and gearbox. The vibration acceleration level can be reduced from 7dB to 4.3dB. Driving the seawater hydraulic piston pump by permanent magnet synchronous motor instead of asynchronous motor is of benefit to eliminating the gearbox and reducing the vibration excitation source. Consequently, the vibration characteristic of the seawater hydraulic piston pump system driven by a permanent magnet synchronous motor is significantly improved.

A Fault Diagnosis Framework for Centrifugal Pumps by Scalogram-Based Imaging and Deep Learning

Centrifugal pumps are the most vital part of any process industry. A fault in centrifugal pump can affect imperative industrial processes. To ensure reliable operation of the centrifugal pump, this paper proposes a novel automated health state diagnosis framework for centrifugal pump that combines a signal to time-frequency imaging technique and an Adaptive Deep Convolution Neural Network model (ADCNN). First, the vibration signals corresponding to different health conditions of the centrifugal pump are acquired. Vibration signals obtained from the centrifugal pump carry a great deal of information and generally, statistical features are extracted from the vibration signals to retain meaningful fault information. However, these features are either insensitive to weak incipient faults or unsuitable for tracking severe faults, thus, decreasing the fault classification accuracy. To tackle this problem, a signal to time-frequency imaging technique is applied to the pump vibration signals. For this purpose, Continuous Wavelet Transform (CWT) is applied to decompose the vibration signals over different time-frequency scales and extract the pump fault information in both the time and frequency domains. The CWT scales form two-dimensional time-frequency images commonly referred to as scalograms. The CWT scalograms are then converted into grayscale images (SGI). Over the past few decades, CNN models have been established as an effective practice to process images for classification and pattern recognition. Consequently, the extracted CWTSGIs are finally provided as inputs to the proposed ADCNN architecture to achieve feature extraction and classification for centrifugal pump faults. The performance of the proposed diagnostic framework (CWTSGI + ADCNN) is validated with a vibration dataset collected from a testbed specifically designed for centrifugal pump diagnosis. The experimental results suggest that the proposed technique based on CWTSGI and ADCNN outperformed existing methods with an average performance improvement of 4.7 – 15.6%.

A Novel Framework for Centrifugal Pump Fault Diagnosis by Selecting Fault Characteristic Coefficients of Walsh Transform and Cosine Linear Discriminant Analysis

In this paper, we propose a three-stage lightweight framework for centrifugal pump fault diagnosis. First, the centrifugal pump vibration signatures are fast transformed using a Walsh transform, and Walsh spectra are obtained. To overcome the hefty noise produced by macro-structural vibration, the proposed method selects the fault characteristic coefficients of the Walsh spectrum. In the second stage, statistical features in the time and Walsh spectrum domain are extracted from the selected fault characteristic coefficients of the Walsh transform. These extracted raw statistical features result in a hybrid high-dimensional space. Not all these extracted features help illustrate the condition of the centrifugal pump. To overcome this issue, novel cosine linear discriminant analysis is introduced in the third stage. Cosine linear discriminant analysis is a dimensionality reduction technique which selects similar interclass features and adds them to the illustrative feature pool, which contains key discriminant features that represent the condition of the centrifugal pump. To achieve maximum between-class separation, linear discriminant analysis is then applied to the illustrative feature pool. This combination of illustrative feature pool creation and linear discriminant analysis forms the proposed application of cosine linear discriminant analysis. The reduced discriminant feature set obtained from cosine linear discriminant analysis is then given as an input to the K-nearest neighbor classifier for classification. The classification results obtained from the proposed method outperform the previously presented state-of-the-art methods in terms of fault classification accuracy.

Experimental Study on Deteriorated Performance, Vibration, and Geometry Changes of an Electrical Submersible Pump Under Sand Water Flow Condition

AbstractIn the oil and gas industry, the proppant backflow from fracturing wells severely reduces the lifespan of widely used downhole electrical submersible pumps (ESPs). In field applications, a minimal sand concentration may cause severe damage to ESPs in a short time. In order to resist the three-body abrasive sand wear, flanged tungsten carbide sleeves are used in ESPs. However, the wear-resistant performance of different pump geometry is not well analyzed and understood. Therefore, a 64 h pump erosion and abrasion test was conducted with water at the pump's best efficient flowrate with a sand concentration of 1 wt% to imitate the damage caused by short-term proppant backflow. The test was divided into several periods, after which the pump performance, paint-removal wear pattern, eroded pump geometries, and stage vibration were measured and recorded. The wear-rate on pump stage geometries gradually decreased at the beginning of 8–16 h. Then, the carbide sleeves started to help sustain the pump rotation. As a result, the wear-rate and pump vibration became relatively stable. Therefore, the wear mechanism in the secondary flow region (seal rings and sleeves) is believed to change from abrasive wear to the combined erosive-abrasive wear. The pump overall performance decreased by approximately 10% after the 64 h test. The performance, pump geometry, and vibration data are previous for understanding wear mechanism, predicting failures, improving pump design, and saving the well service cost.

Electric submersible pump vibration analysis under several operational conditions for vibration fault differential diagnosis

An Electric Submersible Pump (ESP) vibration analysis was performed, considering different wear states and operational conditions. The pumps were tested with different fluid viscosities, operating points, and speeds to evaluate their vibration behavior, with the aim of providing characteristics for non-invasive differential vibration diagnosis. A specific frequency spectrum estimation method is described, focusing on the extraction of frequency component vibration amplitudes used in the petroleum industry-standard vibration analysis. A time-interval definition procedure was proposed to reduce signal amplitude losses due to variation of synchronous operating frequency. The results indicate that the frequency component peak amplitudes can be more accurately identified during synchronous frequency variation by the proposed method than by typical estimation methods. In this study, an ESP vibration differential diagnosis was achieved by analyzing relations between orders of the synchronous frequency, and by distinguishing that the synchronous component amplitude rose approximately proportionally to the square of the rotating speed; this differentiates unbalance fault from a bent shaft or a misalignment. A correlation matrix analysis is provided to demonstrate that variation in the fluid-temperature difference between the pump intake and discharge is related to the vibration amplitude variation in a pump with a vibration fault.

Numerical investigation on vibration and pressure fluctuation characteristics in a centrifugal pump under low flow rate

Vibration characteristic is an important factor in evaluating operation stability of centrifugal pump. The vibration of main shaft was measured using a laser vibrometer, internal flow field was simulated via the shear stress transport turbulence model, and distribution law of vibration and pressure fluctuation in the impeller were analysed to explore the induction factor of vibration and the inherent relationship with pressure fluctuation in a semi-open centrifugal pump under low flow rate condition. Results of the numerical simulation are consistent with the experimental data. In addition to rotation frequency caused by impeller rotation, vibration frequency also includes characteristic frequency with high amplitude induced by unstable flow. The complex vortex in the impeller is composed of tip leakage vortex (TLV), reverse flow vortex, passage vortex and tip separation vortex. The primary tip leakage vortex (PTLV) formed by the streamline spills from 0 to 0.2λ where λ is the dimensionless distance from leading edge to trailing edge collides with tip leakage flow, the leading edge overflow and reverse flow vortex at the frequency of 1.6 fn ( fn is the rotating frequency) and 2.2 fn appear, respectively. The tip separation vortex formed in the tip clearance induced a frequency of 1.2 fn. The frequency of unstable flow phenomenon was consistent with the vibration frequency of main shaft, which induced the vibration of centrifugal pump.

Analysis of oil pump vibration in long distance oil transportation system

The dynamic forces of mechanical and hydraulics may cause vibrations and noises of centrifugal pumps. To prevent the pumps from the vibrations and noises, we investigate the relationship between the oil properties/flowrate and vibration levels. The time-domain analysis and spectral characteristic analysis are used to analyze pump vibration data, it is found that the vibration level is more sensitive for the lightweight oil, the vibration becomes more severe when a specific adjacent pumps run together. Several modification suggestions are provided to the pumping station for preventing pump failure.

Effect of Blade Coating on a Centrifugal Pump Operation under Sediment-Laden Water Flow

Applying a high strength coating on a blade’s surface could significantly prolong the service life of a centrifugal pump under sediment-laden water flow because of its protection. To explore the effect of blade coating, the characteristics of energy, vibration and pressure fluctuation of a centrifugal pump (the specific speed (ns) is 81.46) with different polyurethane coating thickness coefficients were experimentally studied under sediment-laden water flow. Keeping the blade outlet angle, blade inlet angle and blade shape unchanged, the head H and efficiency η under both sediment-laden flow and clear water flow decrease significantly as the coating thickness coefficient increases. The axis rotating frequency and blade passing frequency are the main excitation frequencies of the pump vibration velocity amplitude and outlet pressure fluctuation. The vibration velocity amplitude and outlet pressure fluctuation at the frequency of 1 BPF are the largest. At the frequency of 1 axis rotating frequency, they are the second in all cases. The peak values of both vibration velocity amplitude and outlet pressure fluctuation are proportional to the coating thickness coefficient. An analysis was performed for several increasing coating thicknesses, corresponding to coating coefficients from K0 to K3. When the coating thickness coefficients are K0, K1, and K2, the peak value of vibration velocity amplitude under sediment-laden flow is larger than that under clear water flow, but the very small difference between them undercoating thickness coefficient K3. The peak values of pressure fluctuations under different flow rates decrease first and then increase with the increasing coating thickness coefficient, and lowest points are all located at the coating thickness coefficient K1.

Analysis of fluid-induced force of centrifugal pump impeller with compound whirl

In order to research the fluid-induced force of centrifugal pump impeller with compound whirling, based on the N-S equations, the RNG k-ε turbulence model is applied to simulate the low specific speed centrifugal pump under eccentric assembly condition. The effects of different flow rates, impeller eccentricities and whirl ratios on the fluid-induced force of impeller were investigated. Finally, the fitting models of fluid-induced force with compound whirl were obtained by least square method (LSM). The results imply that the calculated results considering the impeller eccentricity are closer to the experimental data than those without considering the eccentric whirl. In addition, the extremum value of fluid-induced force of impeller has a significant positive correlation with the impeller eccentricity. With the increase of flow rate, the fluid-induced force is non-monotonic. The whirl ratio can change the numbers of peak and valley of fluid-induced force, and the nonlinear fitting model of fluid-induced force using LSM presents high precision. This study can provide important references for the design and fluid-structure interaction (FSI) vibration of centrifugal pump.

Field Oriented Control-Based Reduction of the Vibration and Power Consumption of a Blood Pump

Power quality and energy efficiency are of great importance in motor control. The motor of any medical device needs to have a smooth torque and minimal vibration in order to maximise its energy efficiency and patient comfort. Furthermore, in rotary blood pumps, excessive energy wasted due to vibration is converted into uncontrolled movement of the mechanical parts and thus could reduce the life of the motor-pump. Besides mechanical or hydraulic origin, one of the causes of vibration in any pump is torque ripple resulting from motor phase commutation. In this paper, using relevant equipment, two extreme scenarios were examined for vibration and electrical efficiency comparison due to power quality in a blood pump: one trapezoidal control with a trapezoidal phase current output; the other a field oriented control (FOC) with a non-distorted sinusoidal phase current. The test motor-pump was the Arteriovenous Fistula Eligibility (AFE) System that is used prior to haemodialysis. The trapezoidal technique was implemented utilising the Allegro a4941 fan driver (Allegro Microsystem, 2012), and the FOC technique was implemented using the Texas Instrument digital signal processor (TMS320F28335). The aim was to reduce the energy wasted over vibration, and to achieve smooth operation of the AFE System. Vibration was measured with a one-axis accelerometer; results showed considerably lower vibration due to less current ripple associated with the FOC control as well as lower power consumption.

Investigation on performance of a centrifugal pump with multi-malfunction

Herein, the performance and inner flow characteristics of a single-stage single-suction centrifugal pump with multi-malfunctions (broken blade and seal ring abrasion) were determined through tests and numerical simulation. The vibration, inner flow, pressure, and radial force of the centrifugal pump were analyzed in detail. Compared with those of a normal pump, the head and efficiency of the pump with multi-malfunctions decreased by 10.56 and 10.09%, respectively, under the design flow rate. The general vibration level most significantly increased at the foot of the pump. The axial passing frequency of each measuring point increased in varying degrees, and new characteristic frequencies appeared at 5, 2, and 3 axial passing frequencies. The simulation results showed that in the pump with multi-functions, the pressure gradient near the broken blade was distinctly reduced, and the periodicity of the impeller radial force became weaker and more concentrated, thus exhibiting different performance than the normal pump. The peak-to-peak value of the pressure pulsation near the tongue increased by 8.5%, whereas that at the pump outlet decreased by 6.8%. Moreover, a vortex appeared at the inlet and another at the middle of the impeller, and the low-pressure zone near the impeller inlet expanded to the middle of the impeller. The results of this work can be used as reference for pump fault diagnosis.

Analytical Harmonic Method for Modeling High-Frequency Oscillation With Applications to Aircraft Piston Pump Vibration Analysis

Undesired oscillations are often encountered in controlled systems at steady state due to high-frequency (HF) periodic disturbance and/or feedback noises. This article presents a computationally efficient alternative to derive an analytical harmonic model (AHM) that expresses the oscillatory variable as a series of harmonic kernel vectors and a position-independent harmonic amplitude vector for identifying the dominant harmonic components of the undesired effects on the manipulated variables. Illustrated in the context of an aircraft pressure-controlled piston pump (PC-PP) where the pressure feedback pulsations and the torque disturbances from the piston/slipper assemblies lead to HF swash-plate (SP) oscillation at steady state, the AHM and its significance were investigated experimentally on a PC-PP test-rig capable of simultaneously measuring the HF feedback pressure and SP-angle. Good agreements between the experimental and numerical results validate the AHM, and reveal that the HF SP-oscillation is dominated by its fundamental harmonic component, and primarily contributed by the disturbance torque.

Strategies to reduce norovirus (NoV) contamination from oysters under depuration conditions

Depuration of oysters can effectively reduce levels of E. coli, however, may not be effective in safeguarding against viral contamination (EFSA, 2012). These trials assess the removal of Norovirus Genogroups I and II (NoV GI and GII) and F + RNA bacteriophage genogroup II (FRNAP-II) from oysters under depuration using molecular and viability assay methods. Our results show consistently better removal of NoV GII compared with Nov GI. We found approximately 46% removal of NoV GII at 18 °C after 2 days and 60% after 5 days compared with a maximum of 16% NoV GI removal. Twice the rate of NoV GII removal was achieved at 18 °C compared with 8 °C after 5 days. Results suggest better NoV removal when depuration water salinity is close to that prevailing in the harvesting area. Trials investigating algal feeding, light/dark and disturbance from pump vibration did not show any significant effect.We found that FRNAP-II was more readily removed than NoV. No significant difference was found between the rate of removal (as measured by RT-qPCR) and inactivation (as measured by bioassay) of FRNAP-II. This indicates that reduction in FRNAP-II may be primarily due to physical removal (or destruction) rather than in situ inactivation of the virus.

Experimental analysis of the influence of polymer solutions on performances and cavitation of small size pumps for professional appliances

Pumps used in professional appliances process a solution of water, soils residues and detergents. These affect vapor tension, viscosity and rheology of the solution, mainly due to the presence of surfactants and polymers. Only a few studies have been found on how these substances can influence pump performances. Therefore, an experimental analysis has been carried out with aqueous solutions of a detergent component, the Polyox WSR 301, in the concentration range of 100–7000 ppm, to evaluate their influence on pump performances and cavitation. Some properties of the solutions have been preliminary characterized with a rheometer. Then, each solution has been tested in a dedicated test rig, to compare the performance curves of a centrifugal pump used in professional warewashing machines with those obtained with pure water. A non-intrusive method, based on the investigation of high frequency vibrations and noise signals, has been developed to detect cavitation at its early stage of inception. It was observed that polymer mitigates cavitating pump vibrations, with a reduction of the acceleration to less than one g. The analysis has provided the data necessary for the successive development of a control strategy for pump operation in professional appliances.

A cavitation performance prediction method for pumps PART1-Proposal and feasibility

Pumps are essential machinery in the various industries. With the development of high-speed and large-scale pumps, especially high energy density, high requirements have been imposed on the vibration and noise performance of pumps, and cavitation is an important source of vibration and noise excitation in pumps, so it is necessary to improve pumps cavitation performance. The modern pump optimization design method mainly adopts parameterization and artificial intelligence coupling optimization, which requires direct correlation between geometric parameters and pump performance. The existing cavitation performance calculation method is difficult to be integrated into multi-objective automatic coupling optimization. Therefore, a fast prediction method for pump cavitation performance is urgently needed. This paper proposes a novel cavitation prediction method based on impeller pressure isosurface at single-phase media. When the cavitation occurs, the area of pressure isosurface Siso increases linearly with the NPSHa decrease. This demonstrates that with the development of cavitation, the variation law of the head with the NPSHa and the variation law of the head with the area of pressure isosurface are consistent. Therefore, the area of pressure isosurface Siso can be used to predict cavitation performance. For a certain impeller blade, since the area ratio Rs is proportional to the area of pressure isosurface Siso, the cavitation performance can be predicted by the Rs. In this paper, a new cavitation performance prediction method is proposed, and the feasibility of this method is demonstrated in combination with experiments, which will greatly accelerate the pump hydraulic optimization design.

Vibration analysis of Kartini reactor secondary cooling pump using FFT analyzer

The vibration of the secondary cooling system the Kartini reactor works to remove heat from the primary cooling system so that the heating element stays below the safety limit of the specified operating temperature. One component that is supported is a pump that is needed one of them by the vibration analysis method. By using vibration analysis, the type of cause of damage to the pump can be detected without dismantling the pump, so that it can provide predictability of maintenance time, scheduling repairs, picking up damaged equipment before hazardous needs. Vibration measurement with vibration meter (Lutron VB 8202) is carried out on the bearing housing of the secondary cooling pump motor housing in the direction: vertical, horizontal and axial. The value of the vibration compared with the vibration pump standard (ISO 10816-3). From the results of pump vibration measurements, there are several pump parts whose conditions are classified as vibrations that can cause damage to these components, namely the pump motor section. The average vibration on the pump motor is 5.74 mm / s greater than 4.5 mm/s that is classified as a vibration velocity value which can cause damage to other pump components. The results of the symptom analysis of variations in the vibration of abnormal values in the pump motor are caused by looseness of rotation and damage to roller bearings.

Analysis of sound and vibration interaction on a crack and its use in high-frequency parameter selection for vibro-acoustic modulation testing

Vibro-acoustic modulation (VAM) is a sensitive nonlinear method used to nondestructively detect cracks and other contact-type defects in materials and structures. However, the modulation between two excitation signals in a structure has not been investigated well. In this study, the interactions between the ultrasound (probing), vibration (pumping), and crack are investigated. Using aluminum beam samples, a sweep signal is used as the probing excitation, and synchronic demodulation and a short-time Fourier transform are used to extract the modulation from the output signal. The results demonstrate that the modulation can be affected by the crack position when it is located at the longitudinal resonance node point x0 = L m/n (where L is the beam length, n is the mode number, m is an integer, and 1 ＜ m ＜ n), and both the modulation at the multiples of the number n-order resonance frequencies and peaks on the side of these resonances are much lower. It is also demonstrated that the modulation peak values occur on both sides of the high-frequency structure response resonances. The modulation peak frequencies change with the pumping amplitude; however, the variation is too small to affect the probing frequency selection in our experimental setup. Further analysis suggested that the nonlinear spring model is appropriate for crack simulations to predict modulation distribution and select parameters. The VAM technique exhibited the best crack sensitivity when the probing frequency was selected as the sum or difference of the resonance and pumping frequency. To lock this optimum probing frequency, the minimum sweep range should be twice the beam longitudinal fundamental frequency. Further, the energy dissipation in the crack interface also plays an important role in the modulation and has the potential to be used for crack size estimation with proper excitation. All of the obtained results will aid in understanding the modulation mechanism and making further improvements to the reliability and efficiency of the VAM technique.

Stability Optimization and Analysis of a Bidirectional Shaft Extension Pump

Abstract This paper is to solve the problem of poor stability of bidirectional shaft pumps, under reverse and low-head condition. In this study, computational fluid dynamics (CFD) calculations are carried out and verified by model test, under four theoretical conditions: steady, unsteady, unidirectional, and bidirectional fluid–solid coupling. The S-shaped elbow of bidirectional pump was divided into four schemes according to the ratio b of the centerline's radius. The effects of b value on the efficiency and stability in the forward and reverse condition of the pump device were analyzed and compared. When b value was 0.75, the efficiency and stability of the pump device proved best. The frequency domain of pressure pulsation and dynamic stress of bidirectional pump under zero and design head condition was analyzed. It was found that the bidirectional pump had main frequencies corresponding to 10 and four times the rotation frequency of the runner (fn), for most working conditions. While there is a subfrequency of 14fn in zero head operation, which is similar to the natural frequencies of first- and second-order, calculated in the modal analysis. This may be the cause of the larger vibration of the bidirectional pump when it starts under the condition of zero head.

Internal flow structure, fault detection, and performance optimization of centrifugal pumps

This review mainly summarizes the latest developments in the internal flow field and external characteristics of centrifugal pumps. In particular, the latest findings of centrifugal pumps focused on turbulence and cavitation models, flow visualization methods, and fault detection based on noise and vibration. The external characteristics, cavitation, and vibration of the centrifugal pump were extensively discussed. In addition, advanced multi-objective optimization methods for improving impeller’s efficiency and reducing net positive suction head (NPSH) were briefed. Although some progress was made in this field, there remain many unsolved problems, such as monitoring and modeling of cavitation, rotational stall phenomenon, and discrepancies between simulation and measurement. In the future, researchers are encouraged to employ multi-dimensional flow visualization technologies and high-performance computing facilities to advance existing understandings on these issues and create new research directions.

Dynamic Analysis of the Stick-Slip Phenomenon in an Automotive Water Pump

In this paper, we present a study on the stick-slip torsional vibration of the spinning shaft in an automotive water pump. We propose a dynamic rotor model with a pulley, an impeller, a mechanical seal and a shaft to analyze the stick-slip vibration of a water pump. The dynamic states of the mechanical seal are classified into stick and slip states depending on whether the seal and mating rings of the mechanical seal have relative motion or not. We derived the partial differential equations of motion and the corresponding boundary conditions for each state of the seal. In addition, we established a judgement criterion for the stick and slip states of the seal. After the equations of motion were discretized by a proposed finite element procedure, the dynamic responses of the rotor system of a water pump were computed by using the generalized-a time integration method. Furthermore, we analyzed the effects of various system parameters on stick-slip vibration, including the mass moment of inertia for the pulley, the drag torque at the impeller, the external torque at the pulley, and the normal force between the seal and mating rings.