Rotary Pump Research Articles

Rotor fault diagnosis of centrifugal pumps in nuclear power plants based on CWGAN-GP-CNN for imbalanced dataset

As a crucial device in nuclear power plants, centrifugal pumps undertake the critical role of cooling water circulation. Centrifugal pump rotor misalignment and unbalanced faults cause pump performance degradation, vibration increase, and equipment damage, thus seriously affecting the safety and reliability of nuclear power plants. In the process of centrifugal pump rotor fault, the difficulty in obtaining data samples and the limited amount of data can lead to an imbalance problem between the quantity of normal state and fault state samples in the dataset. In order to solve the problem, this paper proposed a CWGAN-GP model for generating rotor fault data based on CGAN and WGAN-GP models, and combined it with a two-stream CNN model to realize the rotor fault diagnosis with an imbalanced dataset. The quality and performance of the data generated by the proposed method were evaluated and validated in terms of visualization analysis, statistical indicators, and comparison with different data generation models. The results show that the CWGAN-GP model can generate high-quality data. Meanwhile, compared with other models on datasets with different degrees of imbalance, the two-stream CNN model is more effective in fault diagnosis on the expanded dataset by the CWGAN-GP model, and the improvement of fault diagnosis accuracy ranges from 1.40% to 13.33%.

Damage mechanics coupled with a transfer learning approach for the fatigue life prediction of bronze/steel diffusion welded bimetallic material

The bronze/steel diffusion welded (BSDW) bimetallic material is often applied in the rotors of piston pumps to withstand complex alternating loads under high-speed operating conditions. Although diffusion welding is a type of solid-phase welding method to achieve high-quality material connections, the fatigue problems still deserve our attention, especially the very high cycle fatigue (VHCF) and high cycle fatigue (HCF) problems. However, due to the high cost of obtaining data, it is necessary to find an efficient and high-precision fatigue life prediction method for diffusion welded materials with a small sample size. In this study, a novel method continuum damage mechanics − transfer learning method (CDM-TLM) for fatigue life prediction of BSDW material is proposed based on the transfer learning (TL) and continuum damage mechanics − finite element method (CDM-FEM). In comparison with the test results, the predicted values of BSDW material fatigue life all fall within the twice error band of the median values of the test life. The influence of frozen layers during TL and training samples in source and target models on the prediction performance is further discussed. CDM-TLM is an effective life prediction method for high-precision life prediction of BSDW material with a small sample size.

Modal Analysis and Optimization of Fluid-Structure Coupling for Rotor and Inner Cylinder of Vertical Condensate Pump

Background: Low-frequency resonance is one of the common issues encountered during the variable-frequency operation of condensate water pumps. There have been numerous patents and papers proposing solutions to address the low-frequency resonance problem in condensate water pumps. However, the solutions for resonance problems often need to be tailored to specific circumstances. Methods: Based on the acoustic method, the dynamic model of the rotor and inner cylinder of Jiangsu Guohua Chenjiagang Power Plant 2B condensate pump is established to compare the difference between dry modal and fluid-structure coupling modal, the influence of perpendicularity, concentricity and bearing wear on the natural frequency of rotor is studied. Results: The rotor is rigid under normal conditions. When the bearing is worn, the frequency of the rotor will be greatly reduced and may fall into the frequency conversion operation range to excite resonance. The deviation of perpendicularity and concentricity will not directly lead to the decrease of rotor modal but will lead to the increase of bearing stress, aggravate bearing wear, and then affect the rotor modal. As the inner cylinder only relies on the fixed support at the top, the structure stiffness is low, which may lead to low-frequency resonance. By adding two support structures at the guide vane, the first-order modal frequency of the inner cylinder can be increased from 3.29 Hz to 28.88 Hz, effectively avoiding the operating frequency range of the system. Conclusion: This study can guide the optimization of similar pump structures.

Prediction of inlet gas volume fraction of rotary vane pump under variable operational conditions with 1DCNN-TL model utilizing vibration signals

The Rotary vane pump (RVP) exhibits promising potential in the lubricating oil system of aircraft engines. The entrainment of air into the lubricating oil flowing through the pump affects the suction and discharge flow rates of the RVP. Therefore, understanding the inlet gas volume fraction (IGVF) of the RVP is crucial to assess its capability to deliver sufficient lubricating oil for ensuring the safe operation of aircraft engines. This study presents a one-dimensional convolutional neural networks (1DCNN)-based transfer learning (TL) (1DCNN-TL) prediction model to predict IGVF for the RVP using experimental data from gas-liquid two-phase flow in the RVP. The model is pre-trained using the vibration signals under a specific differential pressure between the pump inlet and outlet to enable predictions of the IGVF under varying differential pressures. The 1DCNN serves as pre-trained model for analyzing the outcomes of different transfer tasks. The effect of different frozen layer numbers on training time and prediction accuracy of the neural network is explored. Subsequently, the influence of varied source domain data on prediction accuracy is investigated, revealing that for optimal TL results, stable condition data at 200 kPa should be preferred as the source domain. Then the 1DCNN-TL prediction model of IGVF of RVP under variable operational conditions is determined. The results indicate varying iteration convergence rates of the pre-trained model under a differential pressure of 200 kPa across different transfer tasks, with a final goodness of fit exceeding 0.958 after fine-tuning the model. The model demonstrates the high prediction accuracy and applicability, which can contribute to improving the reliability and safety of aircraft engines.

Measurement and machining error assessment method for cycloid pump rotor profile based on STEP

Abstract The contour shape and machining precision of the rotor of an cycloid pump directly determine the sealing performance of the pump cavity. Precise measurement of contour machining errors is a crucial step in the manufacturing process. However, rotor contour curves are often designed by enterprises based on actual engineering needs, leading to inconsistency between the measured baseline contour and the designed contour, thus failing to accurately reflect the actual machining condition of the rotor. Therefore, this paper proposes a method for measuring the contour of the cycloid pump rotor and evaluating machining errors based on the standard for the exchange of product (STEP) files necessary for product design in manufacturing. Firstly, utilizing NX/OPEN API functions, contour coordinate points and unit normal vectors are obtained from the rotor’s STEP design data. Subsequently, by planning the process of measuring the closed continuous contour of the rotor, the transformation between the workpiece coordinate system and the measurement coordinate system is achieved to position the tested rotor, followed by analyzing the influence of different starting points on error measurement and evaluation determines the optimal starting point. Finally, a measurement sampling point strategy is established to collect data points of the actual machining contour of the rotor. By achieving the best matching between the actual machining contour and the measured baseline contour, a contour deviation calculation model is established. Utilizing gauge blocks enables accurate assessment of pitch deviation, radial runout, and tooth-to-tooth distance deviation, resulting in assessment results that better fit the actual meshing situation of the rotor. Experimental results verifies consistency between the measurements of the one-dimensional probe and Gleason measurements. This theory and method not only expand the measurement range of the one-dimensional probe but also provide more accurate and efficient guidance for the flexible machining of the rotor.

A cavalpulmonary assist device utilising impedance pumping enhanced by peristaltic effect.

Fontan procedure, the standard surgical palliation to treat children with single ventricular defects, causes systemic complications over years due to lack of pumping at cavopulmonary junction. A device developed specifically for cavopulmonary support is thus considered, while current commercial ventricular assist devices (VAD) induce high shear rates to blood, and have issues with paediatric suitability. To demonstrate the feasibility of a small, valveless, non-invasive to blood and pulsatile rotary pump, which integrates impedance and peristaltic effects. A prototype pump was designed and fabricated in-house without any effort to optimise its specification. It was then tested in vitro, in terms of effect of pumping frequency, background pressure differences and pump size on output performance. Net flow rate (NFR) and maximum pressure head delivery are both reasonably linearly dependent on pumping frequency within normal physiological range. Positive linearity is also observed between NFR and the extent of asymmetric pumping. The device regulates NFR in favourable pressure head difference and overcomes significant adverse pressure head difference. Additionally, performance is shown to be insensitive to device size. The feasibility of the novel rotary pump integrating impedance and peristaltic effects is demonstrated to perform in normal physiological conditions without any optimisation effort. It provides promising results for possible future paediatric cavopulmonary support and warrants further investigation of miniaturisation and possible haemolysis.

Rotary pump using underwater electrical discharge

Powerful micropumps and water treatment are essential for biomedical applications using microfluidic circuits. Therefore, we propose a rotary pump using underwater electrical discharge for biomedical applications and elucidate its design concept. Specifically, we demonstrate that by applying high-voltage pulses repeatedly, the rotary device having an asymmetrical antenna structure can rotate with the maximum angular velocity of ∼25 rad s−1, and can produce a net flow with an average velocity of ∼3.2 mm s−1 along with an instantaneous maximum flow of ∼9 mm s−1. In addition, we explain our experimental results fairly well by proposing a simple model that considers the effects of asymmetricity and electric field strength with a steric effect. Our findings should contribute to the microfluidics for biomedical applications.

Visualizing Single V-ATPase Rotation Using Janus Nanoparticles.

Understanding the function of rotary molecular motors, such as the rotary ATPases, relies on our ability to visualize the single-molecule rotation. Traditional imaging methods often involve tagging those motors with nanoparticles (NPs) and inferring their rotation from translational motion of NPs. Here, we report an approach using "two-faced" Janus NPs to directly image the rotation of single V-ATPase from Enterococcus hirae, an ATP-driven rotary ion pump. By employing a 500-nm silica/gold Janus NP, we exploit its asymmetric optical contrast - silica core with a gold cap on one hemisphere - to achieve precise imaging of the unidirectional counter-clockwise rotation of single V-ATPase motors immobilized on surfaces. Despite the added viscous load from the relatively large Janus NP probe, our approach provides accurate torque measurements of single V-ATPase. This study underscores the advantages of Janus NPs over conventional probes, establishing them as powerful tools for single-molecule analysis of rotary molecular motors.

Optimization of rotor profile design and analysis of transient flow fields in an asymmetric singular double claw vacuum pump

The claw vacuum pump is widely used in vacuum industries due to its high-performance, compact structure, and oil-free operation. This study delves into the rotor profile and internal flow field characteristics of an asymmetric singular double claw vacuum pump. Theoretical profile equations for the male-female rotor of claw vacuum pumps were given, and a three-dimensional transient simulation of the internal flow field was carried out using the dynamic mesh reconstruction method. The simulation result was also verified by experiments. Analysis shows that: the radial clearance significantly affects the volumetric efficiency of the claw vacuum pump, with a larger effect than the axial clearance; the maximum instantaneous temperature corresponds to radial clearance, leading to maximum thermal deformation concentrated at the claw tip; thermal deformation is the predominant factor contributing to maximum deformation; the smaller the coefficient of thermal expansion, the less the rotor material affects the claw vacuum pump clearance. Based on these insights, we have innovatively optimized two elements of the theoretical claw vacuum pump rotor profile, i.e., the curvature of the cusp B and three optimized configurations of the complex EH section. The optimization results provide a solid theoretical basis for advancing the design and practical application of this pump type.

The Study Design of a Double-Action Plate Vacuum Pump

Rotary plate vacuum pumps have become widely used as a source of vacuum for milking systems. The main features of a plate vacuum pump include design simplicity, high efficiency, low cost and adaptability to climatic conditions. A plate vacuum pump requires the improvement of specific performance indicators. This refers to the indicator of specific productivity and specific energy intensity. It is possible to improve the vacuum pump by optimizing the design parameters and technological models of operation. The known studies allow the establishment of rational geometric parameters, the number of plates, the ratio of the main dimensions and eccentricity. However, the problem of reducing the degree of uneven air pumping from the vacuum system needs a scientific solution. The use of a vacuum cylinder in a vacuum line of an increased diameter partially solves the problem of vacuum pressure fluctuations. But such a decision requires additional material costs. In addition, the power of a vacuum pump increases to compensate for the pressure losses. In this study, the authors proposed the design of a double-action plate vacuum pump. It was proven that the simultaneous operation of combined rotors with plates shifted by 45° decreased the degree of air pumping by 7.8%. The research results indicated that the productivity of the developed vacuum pump increased by 13.6%. The drive power increased by 12%, and the specific energy intensity was 20% lower than that of vacuum pumps with similar geometric parameters. The relationship between rational kinematic and design parameters of a double-action vacuum pump was established.

Pediatric continuous-flow total artificial heart with rotor axial position tracking technology: First report of in vivo assessment

BackgroundThe pediatric continuous-flow total artificial heart (P-CFTAH) is a novel double-ended centrifugal pump designed with the intent to provide circulatory support for pediatric heart failure. ObjectivesTo enable continuous monitoring of pump hemodynamics, Hall effect sensors (HES) were embedded inside the P-CFTAH design to track both axial movement and position of the pump rotor post-implantation. Herein, we report an early in vivo evaluation of the P-CFTAH with HES, implanted in small-sized ovine models. MethodsFive healthy lambs were used for the P-CFTAH implantation via a full median sternotomy and cardiopulmonary bypass support. Successful evaluation of the P-CFTAH was achieved in four out of five (n = 4, 20.9 ± 1.3 kg). The hemodynamics and operating conditions were continuously recorded with varying pump speeds (2,800-5,000 rpm), systemic/pulmonary vascular resistance ratio, and high- and low-volume conditions. Among the four cases, P-CFTAH with HES embedded in the rotor was used in two cases. ResultsAll surgical procedures were uneventful, and the optimal anatomical fit of the pump was shown in the chest. Differences between the left and right atrial pressures were mostly maintained within the intended limit of ± 10 mm Hg throughout the design range of systemic and pulmonary vascular resistance. The HES accurately traced the rotor position, showing a positive correlation with atrial pressure differences. ConclusionsThe findings suggest that the P-CFTAH has the potential to provide self-balancing circulatory support for pediatric heart failure patients. The study contributes to the development of a pediatric-sized total artificial heart with improved monitoring.

Development and research of diaphragm hydrolic diode for positive displacement pumps

On the analysis of literary sources and working processes of a positive displacement pump we established that a hydrolic diode in positive displacement pumps improves their reliability and their most efficient application is in pumps in which the process of reverse flow into the working cavity into the discharge line is insignificant in time, for example, in spur rotary pumps. We established on comparing the results of a numerical experiment on the flow of a viscous incompressible fluid in a hydrolic diode, that the k-w model most accurately describes the fluid flow in a diaphragm hydrolic diode both quantitatively and qualitatively. The performed parametric analysis of the influence of the main parameters on the fluid flow in the hydrolic diode and the diodicity proved that the distance between the hydrolic diode plates should be within 35–40 mm; the angle of inclination of the plates to the body of the hydrolic diode should be 20°−30°; the number of pairs of plates should be within 7–9 pcs.

Autonomous Fontan pump: Computational feasibility study

ObjectiveAfter Fontan palliation, patients with single-ventricle physiology are committed to chronic circulatory inefficiency for the duration of their lives. This is due in large part to the lack of a subpulmonary ventricle. A low-pressure rise cavopulmonary assist device can address the subpulmonary deficit and offset the Fontan paradox. We investigated the feasibility of a Fontan pump that is self-powered by tapping reserve pressure energy in the systemic arterial circulation. MethodsA double-inlet, double-outlet rotary pump was designed to augment Fontan flow through the total cavopulmonary connection. Pump power is supplied by a systemic arterial shunt and radial turbine, with a closed-loop shunt return to the common atrium (QP:QS 1:1). Computational fluid dynamic analysis and lumped parameter modeling of pump impact on the Fontan circulation was performed. ResultsFindings indicate that a pump that can augment all 4 limbs of total cavopulmonary connection flow (superior vena cava/inferior vena cava inflow; left pulmonary artery/right pulmonary artery outflow) using a systemic arterial shunt powered turbine at a predicted cavopulmonary pressure rise of +2.5 mm Hg. Systemic shunt flow is 1.43 lumped parameter model, 22% cardiac output. Systemic venous pressure is reduced by 1.4 mm Hg with improved ventricular preload and cardiac output. ConclusionsIt may be possible to tap reserve pressure energy in the systemic circulation to improve Fontan circulatory efficiency. Further studies are warranted to optimize, fabricate, and test pump designs for hydraulic performance and hemocompatibility. Potential benefits of an autonomous Fontan pump include durable physiologic shift toward biventricular health, freedom from external power, autoregulating function and exercise responsiveness, and improved quality and duration of life.

Design, Development and Implementation of a Diesel Rotary Injection Pump Mock-up for Autotronics Education and Research

This research endeavors to design and integrate a diesel rotary injection pump instructional tool into the BS in Autotronics program at the University of Science and Technology of Southern Philippines, Cagayan de Oro City, Philippines. The pedagogical tool is expected to significantly enhance the academic performance of BS in Autotronics students by providing them with a comprehensive understanding of the fundamentals of diesel rotary injection pump functionality. The study addresses the knowledge gap in the functionality of diesel rotary pumps, which is perceived as a significant challenge in the program. The learning outcomes demonstrate the development of student's cognitive skills, encompassing the rotary injection pump's theoretical and operational aspects. Furthermore, the actual laboratory activities utilizing the functional components of the mockup provide evidence of the expected manipulative skill set developed during the course coverage, ultimately preparing students for occupational applications in the field of autotronics.

2D thermo-fluidynamic rotary model of an elastocaloric cooling device: The energy performances

Elastocaloric cooling has been considered a promising solid-state technology for cooling and heat pumping among the alternatives to vapor compression, at room temperature range. The technology is based on elastocaloric effect that is a thermophysical phenomenon occurring in materials like Shape Memory Alloys (SMA). The effect is detectable as a temperature change in the material if adiabatically subjected to a forcing field of mechanical nature. The latter provokes to the materials a stress that can derive from tension, compression, bending, torsion solicitations. As a result, the SMA experiments a structural phase change from austenite to martensite (coupled with heat addition) and temperature rise. Dually when the stress is removed, the SMA releases heat with a temperature decrease. In this paper the SUSSTAIN-EL rotary elastocaloric heat pump has been deeply investigated to test the energy performances while it works on open loop and closed loop, through a 2D numerical model based on the finite element method, for cooling and heating operation modes. The device employs a binary NiTi SMA as elastocaloric refrigerant and air as heat transfer medium. A wide set of working conditions has been considered like variable inlet mass flow rate, rotation frequency and thermal loads. The acquired results demonstrate that, both in open and closed loop, the prototype’s energy performances are promising and highly favourable for the intended macroscale collocation of the device.

Structural Analysis and Optimization of Ultra-High-Speed Centrifugal Pump Rotor System Considering Fluid–Structure Interaction

An ultra-high-speed centrifugal pump plays a crucial role as part of an aircraft engine’s fuel supply system. This paper focuses on the coupled vibration and optimization of a parallel double-stage ultra-high-speed centrifugal pump considering fluid–structure interaction (FSI). The accuracy of the numerical calculation is verified and compared with the experimental results. The steady and transient characteristics of the rotor system are analyzed to ensure the operational reliability of the rotor system. Moreover, an orthogonal test is conducted to explore the transient structural characteristics of the rotor system. The existing cross-support structure meets high-speed stability requirements and there is no resonance in the cantilevered rotor system. The maximum and minimum errors for the head of Pump 2 are 4% and 0.7%, respectively. The minimum values for maximum average deformation and maximum average stress are less than 0.31 mm and 245 MPa, respectively, at design conditions. The position of Bearing 1 near the multi-stage impeller has the greatest impact on the deformation and stress of the rotor system, and the deformation and stress increase as the distance increases. The results of this study can provide a valuable reference for the design of ultra-high-speed centrifugal pump rotor systems.

Vibration Energy Harvesting with Printed P(VDF:TrFE) Transducers to Power Condition Monitoring Sensors for Industrial and Manufacturing Equipment

A vibration energy harvesting system based on fully printed piezoelectric transducers is realized. The transducers have a butterfly‐like architecture based on two single‐optimized cantilevers with a resonance frequency tuned to 49.5 Hz and can be easily mounted to an industrial engine. By comparing single‐ and multistack configurations of the piezoelectric layers combined with full‐wave or voltage doubler rectifiers, the power transfer characteristics and impedance can be matched to the electrical requirements of the sensing circuitry. A single stack with 21 μm thickness results in the maximum power output of 14.4 μW at a vibration velocity of 11.5 mm s−1, typical for industrial engines. The system is used to power a wireless sensor node on a 1 kW rotary pump in normal operation. The system can harvest up to 138 mJ within 24 h, sufficient for daily remote monitoring of the engine's vibration spectrum and temperature state. The system is thus suitable as a low‐cost, ecofriendly power source for industrial IoT applications.

Investigation of hydrodynamic lubricant film breakdown between the journal and bearing in a high-speed coolant pump of electric vehicles

The high-speed coolant pump is essential for electric vehicle thermal management, ensuring optimal module temperatures. The pump impeller and bearing are combined into a rotor and then fit on a fixed shaft with a clearance, aiming to generate a complete lubricant film between the stationary journal and rotating bearing during pump operations. However, during the pump durability test under off-design conditions, severe wear occurred on both the journal and bearing. A novel simulation method based on computational fluid dynamics and dynamic mesh is developed to investigate the lubrication failure. User-defined functions are programmed to articulate the simultaneous rotation and whirl of the bearing, and the effects of temperature and cavitation are considered. Both the pump and bearing simulations closely align with experimental results. When the radial force of the pump rotor is steady, the bearing only rotates without whirling, and the bearing load capacity can counteract the maximum radial force of the rotor. However, the rotor experiences fluctuating radial forces over time, primarily attributed to elevated pressure levels at the volute tongue caused by the rotor–stator interaction. This phenomenon results in the bearing to rotate and whirl simultaneously. The load capacity generated by the backward whirl of the bearing is greater than that of the forward whirl. Nevertheless, the bearing whirl initiates a decline in the extremum values of lubricant film pressure. Subsequently, both load capacity and minimum film thickness exhibit a continuous decrease, eventually culminating in the breakdown of the complete lubricant film and resulting in contact wear failure. These new findings contribute to proposing measures to reduce wear under unsteady excitations.

ВЫБОР ВАКУУМНЫХ НАСОСОВ ДЛЯ СУШКИ СЫРОВ

The objective of the study is to develop a methodology for selecting a specific vacuum pump from the manufacturer’s catalogue that would maintain the required parameters during cheese drying. The object of the study is the operation of domestically produced vacuum rotary vane pumps. The following were stu-died for the vacuum chamber: changes in individual parameters, such as air pressure and density, the effect of the initial product mass and the performance of vacuum rotary vane pumps on pressure. At the initial product mass M0 = 0.8 kg, the pressure increases insignificantly, the maximum value is 3.7 kPa; at M0 = 1.5 kg, the maximum pressure increases to 6.4 kPa; at M0 = 1.8 kg – up to 9.0 kPa; at M0 = 2.0 kg – up to 12.7 kPa. It was found that at M0 ≤ 0.8 kg, the drying conditions do not change compared to the control test data. Subsequently, with an increase in the initial product mass, the pressure in the vacuum chamber increases. The problem of selecting the performance of a vacuum vane-rotor pump that ensures drying of 12 kg of product under given conditions is considered. The paper presents a method for calcula-ting the performance of a vacuum pump, providing the necessary parameters for drying cheeses and selecting a specific pump. With an increase in the total volume of the pumped space, the duration of the preliminary drying stage increases. Vacuum drying methods use the latest technologies that minimize da-mage caused by biochemical changes that reduce nutritional value during the drying process. The described method can be used in developing a technology for drying various food products, designing appropriate pumping systems.

Mechanics mode characteristics analysis and numerical analytical optimization study of a three-stage centrifugal pump

To increase the accuracy of an analytic method based on the concentrated-mass approach for solving the mechanical operating modal characteristics of complete impellers and impellers with balancing holes in a centrifugal-pump rotor system, we establish a mathematical model and a three-dimensional simulation model for a double-supported three-stage centrifugal-pump rotor system. By comparing the modal results obtained from the two models, we propose a mathematical model that integrates the optimization of mass-distribution methods and bending stiffness correction coefficients, and we derive an optimized mathematical model for rotors with balancing holes. The effectiveness of the optimized mathematical model is validated via three-dimensional simulation, and the influence of balancing holes on the wet modes is analyzed. The results show that the wet natural frequencies are lower than the dry ones and that the wet natural frequencies obtained from analytical calculations are consistently higher than those obtained from three-dimensional simulation results. The optimized mathematical model significantly improves the accuracy of the wet modal characteristics for both complete impellers and impellers with balancing holes, with the errors in the low-order natural frequencies reduced by more than 50%. Under the same hole spacing, the natural frequencies of the three-stage centrifugal pump rotor system decrease with increasing hole diameter slightly. Under the same hole diameter, the natural frequencies of the rotor system increase slightly with the hole spacing. The effect of stiffness changes caused by balancing holes on the natural frequencies is larger than the effect of mass changes.