Search Results (56)

As a highly integrated and compact power unit, the motor-pump finds critical applications in emerging electric vehicle (EV) domains such as electro-hydraulic braking and steering systems, where its vibration and noise performance directly impacts cabin comfort. A key factor limiting its NVH (Noise, Vibration, and Harshness) performance is the electromagnetic vibration and noise induced by the cogging torque of the built-in brushless DC motor (BLDCM). Traditional suppression methods that rely on stator auxiliary slots exhibit certain limitations. To address this issue, this paper proposes a collaborative optimization method integrating multi-parameter scanning and response surface methodology (RSM) for the design of auxiliary slots on the motor-pump’s stator teeth. The approach begins with a multi-parameter scanning phase to identify a promising region for global optimization. Subsequently, an accurate RSM-based prediction model is established to enable refined parameter tuning. Results demonstrate that the optimized stator structure achieves a 91.2% reduction in cogging torque amplitude for the motor-pump. Furthermore, this structure effectively suppresses radial electromagnetic force, leading to a 5.1% decrease in the overall sound pressure level. This work provides a valuable theoretical foundation and a systematic design methodology for cogging torque mitigation and low-noise design in motor-pumps. Full article

The aim of this study is to compare submerged vortical structures for a pump mounted in a pump intake without any anti-vortex devices (AVDs), with a trident-like AVD or with a cone AVD. Another aim is to compare the pump characteristics (head, efficiency, power input and radial forces) of these pump arrangements via CFD simulation along with experimental measurements in a closed circuit. The numerical simulation of unsteady multiphase flow is established by means of computational fluid dynamics (CFD) and the volume of fluid (VOF) method. To predict vortical structures in the vicinity of the pump suction bell, the unsteady Reynolds-averaged Navier–Stokes equations (URANS) are solved together with the scale-adaptive simulation (SAS) turbulence model. For each AVD configuration, integral characteristics like the head, power input, efficiency and forces acting on the pump rotor are also evaluated. The numerical results show that the configuration with the cone AVD exhibits the best performance (from the point of view of both hydraulic efficiency and vorticity strength), but it requires a larger distance between the intake bottom wall and the pump bellmouth. The submerged vortices are quite stable when using an AVD, but rather unsteady without any anti-vortex tool. Full article

As critical industrial equipment, the operational stability of a centrifugal pump is profoundly affected by hydraulic radial forces acting on the impeller. However, existing research has limitations in systematically characterizing time-varying force patterns, elucidating the correlations between fluid–structure interaction (FSI) and vibration and noise, and developing multi-operating condition analysis methodologies. This study focuses on a horizontal end-suction centrifugal pump, integrating computational fluid dynamics (CFD) simulations to develop a transient radial force dataset covering nine operating conditions ranging from 0.4 Q_n to 1.2 Q_n. Feature engineering was utilized to extract 23 time-frequency domain features. Through Pearson correlation analysis and agglomerative hierarchical clustering (AHC) algorithms, multi-operating condition classification patterns of hydraulic radial forces were unveiled. Key findings include: (1) the X/Y directional force components exhibit distinct anisotropic correlations with the flow rate; (2) hierarchical clustering based on cosine distance and average linkage divides operating conditions into low, medium, and high flow regimes; (3) feature redundancy elimination requires balancing statistical metrics with physical interpretability. This work proposes an unsupervised learning framework, offering a data-driven approach for the hydraulic optimization of centrifugal pumps and intelligent diagnostics, with engineering significance for improving equipment reliability and operational efficiency. Full article

This article presents a comprehensive experimental and theoretical study and substantiation of the hydraulic parameters of a prototype multi-gear pump. The proposed pump design, which features one drive gear and four driven gears, aims to address the common disadvantages of traditional gear pumps, including radial force imbalance, uneven flow, high acoustic noise, and increased fluid leakage. Tests of the prototype multi-stage pump were conducted on a specialized test stand in the “Hydraulics” workshop of “Hansa-Flex Hydraulik Almaty” LLP. Experimental analysis, supported by theoretical calculations, established the optimal operating speed range for the prototype to be between 900 and 1450 rpm, with the volumetric efficiency remaining stable between 70% and 88% when using VMGZ hydraulic oil (45 cSt). A significant deterioration in performance, including a sharp drop in volumetric efficiency to 30% and a decrease in the pressure generated, was observed at rotational speeds below 900 rpm due to an increase in internal leaks. In addition, this study examined the effect of kinematic viscosity, which revealed a 15–20% decrease in performance and power when using a fluid with lower viscosity (15 cSt) with a slight increase in noise level. This study also examines in detail the linear relationship between useful power and pressure in the system and analyzes noise characteristics under various operating conditions. Full article

Centrifugal pumps are essential in various industries, where their operational stability and efficiency are crucial. This study aims to analyze the composition and variation characteristics of the hydraulic radial force on the impeller using a data-centric approach based on computational fluid dynamics (CFD) datasets, providing guidance for optimizing impeller design. A high-precision CFD simulation on a six-blade end-suction centrifugal pump generated a comprehensive hydraulic load dataset. Data analysis methods included exploratory data analysis (EDA) to uncover patterns and trigonometric function fitting to model force variations accurately. Results revealed that the hydraulic radial force exhibits periodic behavior with a dominant blade passing frequency (BPF), showing minimal fluctuations at the rated flow rate and increased fluctuations as flow deviates. Each blade’s force could be approximated by sine curves with equal amplitudes and frequencies but successive phase changes, achieving high fitting quality (R² ≥ 0.96). The force on the impeller can be decomposed into the contributions of each blade, with symmetric blades canceling out the main harmonics, leaving only constant terms and residuals. This study provides insights into force suppression mechanisms, enhancing pump stability and efficiency, and offers a robust framework for future research on fluid–structure interactions and pump design. Full article

Pneumatic artificial muscles (PAMs) consist of an elastomeric bladder wrapped in a Kevlar braid. When inflated, PAMs expand radially and contract axially, producing large axial forces. PAMs are often utilized for their high specific work and specific power, as well as their ability to produce large axial displacements. Although the axial behavior of PAMs is well studied, the radial behavior has remained underutilized and is poorly understood. Modeling was performed using a force balance approach to capture the effects that bladder strain and applied axial load have on the anchoring force. Radial expansion testing was performed to validate the model. Force due to anchoring was recorded using force transducers attached to sections of aluminum pipe using an MTS servo-hydraulic testing machine. Data from the test were compared to the predicted anchoring force. Radial expansion in large-diameter (over 50.8 mm) PAMs was then used in worm-like robots to create anchoring forces that allow for a peristaltic wave, which creates locomotion through acrylic pipes. By radially expanding, the PAM presses itself into the pipe, creating an anchor point. The previously anchored PAM then deflates, which propels the robot forward. Modeling of the radial expansion forces and anchoring was necessary to determine the pressurization required for proper anchoring before slipping occurs due to the combined robot and payload weight. Full article

A reduction of forces acting between the railway track and the vehicle is one of the key issues in the design of modern rolling stock. Because the capabilities of reducing wheel–rail contact forces in track curves by conventional methods are encountered at their limits, innovative approaches in the design of vehicle suspension and wheelset guidance occur. Among them, an active wheelset steering appears to be very promising. However, an active wheelset steering system is rather complicated and expensive and raises many safety issues. Therefore, a passive hydraulic system that links longitudinal motions of axle boxes is proposed. The system is relatively simple and, compared to the active wheelset steering, does not need any energy supply or sensor system for the detection of a track shape. Two arrangements of the hydraulic system had been proposed and implemented in a simulation model. The simulation model is based on a cosimulation of two separate models, a multibody model of an electric locomotive, and a model of the hydraulic system. The goal of this study is to evaluate the contribution of the hydraulic system to the natural radial alignment of wheelsets in curves and thus to reduce the wear of wheels and to determine the parameters of the hydraulic system to maximize the wear reduction benefits while minimizing a decrease in critical speed. Simulations of a vehicle running in various scenarios, including a run in a real track section of a length of 20 km, have been performed. As a criterion for the wear of wheels and rails, a T-gamma wear number was used, from which a sum of frictional work in wheel–rail contacts was calculated. The results of the simulations and the comparison of hydraulic axle box connection systems and a standard locomotive are presented and discussed in the paper. The results obtained confirmed a significant potential benefit of the proposed hydraulic system in reducing wheel wear on curved tracks. Full article

Lead–Bismuth Eutectic (LBE) is a very dense medium whose specific gravity is more than 10 times that of water. The unsteady hydraulic exciting force generated by the rotor–stator interaction (RSI) is significantly increased in the LBE pump, which has an important influence on the stable operation of the pump. The clearance between the vaned diffuser inlet and the impeller outlet has great influence on the rotor–stator interaction. This paper studies the unsteady flow characteristics in pumps with different rotor–stator clearance in different flow rates and transported mediums. The results show that at the design point, the head and efficiency of the pump when transporting LBE are 3.52% and 8.05% higher than those when transporting water. The pressure fluctuation distribution is similar at different positions inside the pump when transporting LBE and water, but the dimensionless pressure fluctuation coefficient is slightly larger when transporting water. The radial force in the pump shows a larger amplitude of 6BPF frequency with small clearance ratios, and the frequency is related to the guide vane number. When the clearance ratio increases from 1.03 to 1.13, the amplitude of 6BPF keeps decreasing. The amplitude at a clearance ratio of 1.13 decreased to 4.7% of that at 1.03. The research presented in this paper could provide some references for the design of the clearance between the rotor–stator parts in the LBE pump. Full article

In order to study the influence of split blades on the turbine force characteristics and fluid–structure coupling characteristics of pumps, this paper selected the IS 80-50-315 centrifugal pump, used as a reverse-acting hydraulic turbine, as the research object, optimized the original pump-acting turbine impeller, and adopted different combinations of long and short blades. Based on the SIMPLE algorithm and RNG k–ε turbulence model, a complete three-dimensional unsteady numerical simulation was conducted on the internal flow field of the pump-turbine. The results show that the split blades reduce the radial and axial forces. The deformation patterns of rotor components in the two pump types used as turbine models were similar, with deformation gradually decreasing from the inlet to the outlet of the impeller. The equivalent stress distribution law of the rotor components of the two pump turbine models has also been found to be similar, with the maximum stress occurring at the connection between the blades and the front and rear cover plates and the minimum stress occurring at the outlet area of the impeller and the maximum shaft diameter of the pump shaft. The maximum deformation and stress of the rotor components in the split blade impeller model were smaller than those in the original impeller model. Full article

A new type of elliptical cyclone separator has been proposed recently, but the flow field characteristics within the industrial device still need to be further investigated. In this paper, the characteristics of the flow field and particle motion inside the circular cyclone and the elliptical cyclone (with a long-to-short axis ratio of 1.2), with the equivalent hydraulic diameter of 300 mm, are comparatively analyzed using CFD methods. The results show that there is a significant change in the flow field distribution of the elliptical cyclone compared to the conventional circular cyclone. The static pressure gradient of the elliptical cyclone is anisotropic in the radial direction. The overall tangential velocity value is reduced, which reduces friction loss and makes the pressure drop of the elliptical cyclone significantly lower. More importantly, an acceleration/deceleration phenomenon of the airflow velocity occurs in the elliptical separator along the horizontal circumference, that is, the flow field is transformed into a circumferential fluctuating cyclonic field. This phenomenon induces an additional inertial separation effect that compensates for the unfavorable effects caused by the reduced centrifugal strength. Due to the coupling of centrifugal force and additional inertia effect, the residence time of small particles with a diameter of 1 micron in the elliptical cyclone is shorter, which helps to reduce the backmixing of particles and improves the separation efficiency of the elliptical cyclone. This study reveals the unique flow field characteristics of industrial elliptical cyclones, which is helpful to further understand the particle separation mechanism in the circumferential wave swirl field. Full article

The axial-flow impellers are widely applied to industry due to their excellent hydraulic performance and simple structure, but they may be affected by their eccentricity during operation. This study compared and studied the effects of the axial-flow eccentricity of an impeller on hydraulic performance, impeller radial force, and downstream pressure pulsation of the unit. The research results indicate that impeller eccentricity has a small effect on hydraulic performance. Compared with the design conditions, the efficiency, power, and head changes caused by impeller eccentricity are all less than 1%, but the impeller eccentricity leads to a sharp increase in the radial force of the impeller. Under the design conditions, the average value of the radial force of the impeller is 31.38 N; under eccentric conditions, the average value of the radial force of the impeller increased by nine times, reaching 316.30 N. By analyzing the pressure pulsation signals decomposed by the VMD method, it is shown that the influence of eccentricity on pressure pulsation is mainly reflected in the increase in impeller frequency on pressure pulsation. Under design conditions, the corresponding amplitude of the impeller frequency is 2.6; under eccentric conditions, the amplitude corresponding to the impeller frequency increased by 100 times, reaching 274.4. This study elucidates the specific effects of axial impeller eccentricity, providing theoretical guidance for the safe and stable operation of axial-flow units, and has important engineering significance. Full article

In deep-sea mining hydraulic lifting systems, centrifugal pumps are very important as power units. In the process of transportation, the fluid prewhirl phenomenon in the impeller inlet will lead to changes in the state of motion of the particles and fluid and cause the wear of the inlet pipe, which can lead to centrifugal pump failure in serious cases. In this paper, a numerical simulation of the centrifugal pump is carried out based on the CFD-DEM coupling method to analyze the influence of the prewhirl on the wear of the inlet pipe. The results show that the velocity streamline near the impeller inlet position changes significantly. The flow field velocity increases along the radial direction of the inlet pipe, and it has a maximum value at r/R = 0.98. The prewhirl flow pulls the particles to change their original motion direction, and the area where the particles are subjected to high fluid force is concentrated between 0.5 d/D and 1 d/D, about 0.015 to 0.018 N, resulting in the uneven distribution of particles. The high-wear area appears in the bottom-left area (specifically, L4, L9, and L13), and this is also the location of the largest cumulative force; the high-wear area shows a triangle. The collision energy loss of particles increases due to the influence of the prewhirl, which leads to an increase in wear. Full article

The dynamic model of cavitation bubbles serves as the foundation for the study of all cavitation phenomena. Solving the cavitation bubble dynamics equation can better elucidate the physical principles of bubble dynamics, assisting with the design of hydraulic machinery and fluid control. This paper employs a fourth-order explicit Runge–Kutta numerical method to solve the translational Keller–Miksis model for cavitation bubbles. It analyzes the collapse time, velocity, as well as the motion and force characteristics of bubbles under different wall distances γ values. The results indicate that as the distance between the cavitation bubble and the wall decreases, the cavitation bubble collapse time increases, the displacement of the center of mass and the amplitude of translational velocity of the cavitation bubble increase, and the minimum radius of the cavitation bubble gradually decreases linearly. During the stage when the cavitation bubble collapses to its minimum radius, the Bjerknes force and resistance experienced by the bubble also increase as the distance to the wall decreases. Especially in the cases where γ = 1.3 and 1.5, during the rebound stage of the bubble, the Bjerknes force and resistance increase, causing the bubble to move away from the wall. Meanwhile, this study proposes a radiation pressure coefficient to characterize the radial vibration behavior of cavitation bubbles when analyzing the radiation sound pressure. It is found that the wall distance has a relatively minor effect on the radiation pressure coefficient, providing an important basis for future research on the effects of different scale bubbles and multiple bubbles. The overall idea of this paper is to numerically solve the bubble dynamics equation, explore the characteristics of bubble dynamics, and elucidate the specific manifestations of physical quantities that affect bubble motion. This provides theoretical references for further engineering applications and flow analysis. Full article

This article discusses the challenges in preventing workpiece damage due to impacts in electro-hydraulic loading systems, especially in unknown environments. We propose an innovative compliance control strategy, synergizing a series elastic actuator with impedance control to significantly mitigate impact forces between the mechanism and test workpieces. The controller consists of two loops: an internal loop and an outer loop. The internal loop integrates a position loop utilizing a radial basis function observer within a backstepping control framework, effectively countering the nonlinear dynamics of hydraulic actuators and ensuring precise trajectory tracking. The outer loop advances traditional impedance control by adaptively modifying the damping coefficient, resulting in a straightforward and easily implementable damping control law. For the unknown environment parameters, our system employs a parameter estimation law to estimate the unknown environmental stiffness and position parameters. The effectiveness of this strategy has been verified through comparative simulation with traditional impedance control, indicating that the proposed method can not only effectively reduce contact shock in unknown environments, improve response speed, and reduce overshoot, but also improve steady-state accuracy. We provided a feasible control scheme for similar systems to ensure precise and safe operation. Full article

Compared to traditional centrifugal pumps, magnetic pumps are widely used in industries such as chemical, pharmaceutical, and petroleum due to their characteristics of leakage-free operation and the ability to transport toxic and corrosive fluids. However, the efficiency of magnetic pumps is relatively low. Improving the efficiency of pumps helps to reduce energy loss and lower industrial costs. In this study, a magnetic pump was chosen as the research subject. The study aims to improve the efficiency and stability of the magnetic pump by optimizing the impeller blades based on the load curve. A combined approach of a numerical simulation and experimental verification was used to investigate the impact of the anterior loading point (AL), posterior loading point (PL), and slope (SL) in the blade loading curve on the pump’s performance. The slope, which had the most significant impact on pump performance, was selected as the dependent variable to analyze the internal pressure pulsation and main shaft radial force of the magnetic pump. The research found that the hydraulic performance test results of the magnetic pump were in good agreement with the simulation results. When efficiency is used as the optimization objective, the anterior loading point should be moved as far back as possible, and the posterior loading point should be moved as far forward as possible. Through the study of internal pressure fluctuations and radial forces within the pump, the radial force distribution is sequentially as follows: the anterior loading method, posterior loading method, and middle loading method at a rated flow rate. The maximum pressure pulsation amplitude was near the volute casing diffuser area. Compared to the original pump, the optimized magnetic pump showed a 5.05% improvement in hydraulic efficiency under the rated conditions. This research contributes to enhancing the performance and efficiency of magnetic pumps, making them more suitable for various industrial applications. Full article