Hydraulic Pump Research Articles

INVESTIGATION OF IMPELLER BLADES DESIGN FOR AXIAL FLOW PUMP USING COMPUTATIONAL FLUID DYNAMICS

The investigation of the impeller blade design for axial flow pumps used in power transformers is discussed in this paper. Due to the symmetry of the blade type, axial pumps typically have efficiency levels that are significantly lower than those of classical pumps. In this study, the geometry of the blades is modified to achieve a high efficiency in an axial pump by concentrating on a pump impeller. CF Turbo is the proprietary program used in this simulation. The computational Fluid Dynamics results for hydraulic efficiency, head torque, and pump torque were compared. To identify the key effects and their ideal design factors, Orthogonal Array, Analysis of variance and optimization techniques are used. The best ideal solution for satisfying the pump torque and head limitations is discovered when an effective design variable in impeller blades is taken into account.

A Novel Method for the Numerical Investigation of Pendulum Slider Pumps

Inadequate lubrication might lead to high friction and wear and can ultimately translate in a higher dissipation of energy, initiation and propagation of fracture and material fatigue. These occurrences are avoided or delayed thanks to an efficient lubricating system. The core of a reliable system is the hydraulic pump which, in the automotive field, is also responsible for power transmission and cooling. Given the importance of such components, improving reliability and performance of the pumps is a topic that is greatly pursued by manufacturers. A machine that is infrequently addressed in the open literature of the fluid power field is the pendulum slider pump. This kind of machine has the makings of high durability performance, short response time, and significant ability to withstand flow contamination by solid particles. Considering the available literature, no Computational Fluid Dynamics (CFD) studies have been presented so far. Among the complexities that hindered the application of CFD to this machine, motion complexity and narrow gaps make the development of a numerical algorithm for its modelling non-straightforward. In this work, the authors present the development and the application of a CFD model for the simulation of pendulum slider pumps. The structured mesh generation process has been successfully applied to a state-of-the-art pendulum slider pump for automotive applications, and the outcome of the numerical investigation has been validated against an on-purpose built test bench. The results both in terms of variable displacement and fixed displacement behaviour are shown. This work proofs the suitability of the developed model for the analysis of hydraulic pendulum slider pumps.

Bio-SHARPE: Bioinspired Soft and High Aspect Ratio Pumping Element for Robotic and Medical Applications.

The advent of soft robots has solved many issues posed by their rigid counterparts, including safer interactions with humans and the capability to work in narrow and complex environments. While much work has been devoted to developing soft actuators and bioinspired mechatronic systems, comparatively little has been done to improve the methods of actuation. Hydraulically soft actuators (HSAs) are emerging candidates to control soft robots due to their fast responses, low noise, and low hysteresis compared to compressible pneumatic ones. Despite advances, current hydraulic sources for large HSAs are still bulky and require high power availability to drive the pumping plant. To overcome these challenges, this work presents a new bioinspired soft and high aspect ratio pumping element (Bio-SHARPE) for use in soft robotic and medical applications. This new soft pumping element can amplify its input volume to at least 8.6 times with a peak pressure of at least 40 kPa. The element can be integrated into existing hydraulic pumping systems like a hydraulic gearbox. Naturally, an amplification of fluid volume can only come at the sacrifice of pumping pressure, which was observed as a 19.1:1 reduction from input to output pressure. The new concept enables a large soft robotic body to be actuated by smaller fluid reservoirs and pumping plant, potentially reducing their power and weight, and thus facilitating drive source miniaturization. The high amplification ratio also makes soft robotic systems more applicable for human-centric applications such as rehabilitation aids, bioinspired untethered soft robots, medical devices, and soft artificial organs. Details of the fabrication and experimental characterization of the Bio-SHARPE and its associated components are given. A soft robotic squid and an artificial heart ventricle are introduced and experimentally validated.

Light-powered self-oscillation in liquid crystal elastomer auxetic metamaterials with large volume change

Self-oscillation can harvest energy directly from the environment to maintain its motion and is characterized by its autonomy, with various promising applications in the fields of actuators, soft robots and medical devices. Limited to conventional materials, challenges remain in designing novel self-oscillating systems. Auxetic metamaterials can exhibit exceptional properties of negative Poisson's ratio and volume expansion, and the integration of metamaterial structures into self-oscillation can provide additional functionality and improve existing properties and its application. This paper proposes a liquid crystal elastomer (LCE) auxetic metamaterial, and theoretically investigates the self-oscillation of the LCE auxetic metamaterial-mass system under steady illumination. The system can undergo a supercritical Hopf bifurcation between the static pattern and self-oscillation pattern, which arises from the light-driven contraction of LCE fibers and is maintained by light energy input from the environment to compensate for the damping dissipation. This paper also investigates the Hopf bifurcation conditions, as well as the vital systematic parameters affecting frequency and amplitude of the self-oscillation pattern in detail. Different from the existing self-oscillating systems, this LCE metamaterial structure can provide additional functionality and potentially improve existing properties such as large volume change. More generally, the idea of integrating LCE fibers into the re-entrant honeycomb lattices can be applied to other auxetic structures such as arrows and chirality, and it is expected to offer more diverse design ideas of metamaterial and motion control for artificial hearts, hydraulic pumps, sensors, and energy harvesters.

SISTEM DE ACȚIONARE ELECTRICĂ PENTRU ECHIPAMENT DE RECOLTAT BIOMASA ACVATICA, ALIMENTAT DIN BATERII Li-ION

The development of an electric vehicle harvester for aquatic vegetation is a technical challenge for researchers due to specific requirements: high-torque operation at low travel speeds, high maneuverability, high load capacity, low draught, and affordable price. The collective of authors proposed an electro-hydraulic architecture based on paddles driven by hydraulic motors for propulsion and auxiliary services also driven by motors and hydraulic actuators. The proposed energy source for the aquatic harvester is electric batteries, it was developed a system of 33 kWh Li-Ion batteries connected in parallel, which power an electronic converter and a 14.5 kW rated power electric motor that drives a hydraulic double-circuit pump. The vehicle can be controlled remotely. The paper presents the prototype made and the results obtained during laboratory tests performed for the electric powering system.

Dynamic modeling and control of hydraulic driven payload anti-swing system for shipborne cranes

Shipborne cranes are widely used in marine engineering and are employed in more diversified working scenes. However, due to the extensive swing range of ships, it is impossible to locate the payload accurately. A constant tension control method of payload anti-swing is proposed based on the principle of linear velocity feedback. This paper establishes a dynamic model of the payload anti-swing system driven by hydraulic motors. The characteristics of the payload swing and the cable tension are obtained through the dynamic simulation. The simulation and experimental results show that the constant tension control method significantly suppresses the shipborne crane’s payload swing, and the payload anti-swing effect reaches 73% and 85.6%. It is also found that the payload swings asymmetrically under external excitation. In addition, the effects of payload asymmetric swing on cable tension, payload swing angle, and the hydraulic pump output oil pressure are studied by a payload asymmetric swing experiment, and the results show that the proposed method also has a good suppression effect on the asymmetric payload swing.

Piezo-Transmissive Structure Using a Multi-layered Heterogeneous Film for Optical Transmittance Modulation.

As the damage caused by the recent climate crisis increases, efforts are being made to develop low-power and high-efficiency technologies to reduce pollution for energy production worldwide. Among them, research on the mechano-responsive optical transmittance modulation technology is being actively conducted as it can be applied to various application fields for reducing energy consumption: low-power sensors and smart windows. The piezo-transmittance structure, which is one of the optical transmittance modulation structures, has fewer constraints on the installation environment; therefore, many applications have been proposed. However, it is still challenging to fabricate a piezo-transmittance structure with a large-area production, high throughput, and good tunability because of complex curing and dissolution processes. Herein, we present an efficient fabrication method for a multi-layered piezo-transmittance structure using a large-area abrasive mold and thermal imprinting process. The piezo-transmittance performance (e.g., sensitivity and relative change of transmittance) shows temperature/humidity-independent characteristics and can be designed by tuning design parameters such as the number of layers, abrasive grade, and film material. Also, the surrogate model of the performance obtained from the Monte Carlo simulation and prediction model can offer tunability for various applications. Finally, we demonstrated two energy-efficient applications: the smart window integrated with a hydraulic pump showed high thermal efficiency in indoor environment control, and the telemetry system was demonstrated to measure pressure remotely.

A Computer-Aided Intelligent Fault Diagnosis Method for Axial Hydraulic Piston Pump

<p>Axial hydraulic piston pump is widely used in industrial production due to its high pressure resistance and large displacement characteristics, but high pressure and large displacement are also the main causes of piston pump failure. Starting from the fault mechanism of the axial hydraulic piston pump, this paper analyzes and studies the signal characteristics of the fault, and establishes the fault signal acquisition and analysis model. Finally, it discusses the construction of the diagnosis system from both hardware and software, so that the processed typical fault signals can be sent into the intelligent diagnosis system to determine the fault type. Finally, the method in this paper is verified by experiments, which proves the reliability and effectiveness of the diagnosis system.</p> <p> </p>

Industrial Transfer Learning for Multivariate Time Series Segmentation: A Case Study on Hydraulic Pump Testing Cycles.

Industrial data scarcity is one of the largest factors holding back the widespread use of machine learning in manufacturing. To overcome this problem, the concept of transfer learning was developed and has received much attention in recent industrial research. This paper focuses on the problem of time series segmentation and presents the first in-depth research on transfer learning for deep learning-based time series segmentation on the industrial use case of end-of-line pump testing. In particular, we investigate whether the performance of deep learning models can be increased by pretraining the network with data from other domains. Three different scenarios are analyzed: source and target data being closely related, source and target data being distantly related, and source and target data being non-related. The results demonstrate that transfer learning can enhance the performance of time series segmentation models with respect to accuracy and training speed. The benefit can be most clearly seen in scenarios where source and training data are closely related and the number of target training data samples is lowest. However, in the scenario of non-related datasets, cases of negative transfer learning were observed as well. Thus, the research emphasizes the potential, but also the challenges, of industrial transfer learning.

Soft Electromagnetic Motor and Soft Magnetic Sensors for Synchronous Rotary Motion.

To create fully-soft robots, fully-soft actuators are needed. Currently, soft rotary actuator topologies described in the literature exhibit low rotational speeds, which limit their applicability. In this work, we describe a novel, fully-soft synchronous rotary electromagnetic actuator and soft magnetic contact switch sensor concept. In this study, the actuator is constructed using gallium indium liquid metal conductors, compliant permanent magnetic composites, carbon black powders, and flexible polymers. The actuator also operates using low voltages (<20 V, ≤10 A), has a bandwidth of 10 Hz, a stall torque of 2.5-3 mN·m, and no-load speed of up to 4000 rpm. These values show that the actuator rotates at over two orders-of-magnitude higher speed with at least one order-of-magnitude higher output power than previously developed soft rotary actuators. This unique soft rotary motor is operated in a manner similar to traditional hard motors, but is also able to stretch and deform to enable new soft robot functions. To demonstrate fully-soft actuator application concepts, the motor is incorporated into a fully-soft air blower, fully-soft underwater propulsion system, fully-soft water pump, and squeeze-based sensor for a fully-soft fan. Hybrid hard and soft applications were also tested, including a geared robotic car, pneumatic actuator, and hydraulic pump. Overall, this work demonstrates how the fully-soft rotary electromagnetic actuator can bridge the gap between the capabilities of traditional hard motors and novel soft actuator concepts.

PrecTime: A deep learning architecture for precise time series segmentation in industrial manufacturing operations

The fourth industrial revolution creates ubiquitous sensor data in production plants. To generate maximum value out of these data, reliable and precise time series-based machine learning methods like temporal neural networks are needed. This paper proposes a novel sequence-to-sequence deep learning architecture for time series segmentation called PrecTime which tries to combine the concepts and advantages of sliding window and dense labeling approaches. The general-purpose architecture is evaluated on a real-world industry dataset containing the End-of-Line testing sensor data of hydraulic pumps. We are able to show that PrecTime outperforms five implemented state-of-the-art baseline networks based on multiple metrics. The achieved segmentation accuracy of around 96% shows that PrecTime can achieve results close to human intelligence in operational state segmentation within a testing cycle.

Impact Analysis of Worn Surface Morphology on Adaptive Friction Characteristics of the Slipper Pair in Hydraulic Pump

The hydrostatic bearing slipper pair of the hydraulic pump has a unique adaptive friction characteristic, which has a better friction reduction and anti-wear ability than the general sliding friction pair, and also has a certain recovery effect on the performance degradation caused by the early wear of the slipper. This paper attempts to reveal the friction adaptive mechanism. Based on the fractal theory, two fractal parameters of fractal dimension and scale coefficient are used to characterize the surface morphology of the slipper mathematically, and the adaptive friction mechanism model is established by combining the friction coefficient equation. The effects of different fractal parameters on the friction coefficient and other performance parameters of slipper pairs are obtained by means of the numerical analysis method. The wear test was carried out by replacing specimens at different intervals to observe the worn surface morphology and the degradation process of the slipper to verify the correctness of the theoretical results. The results show that the friction performance and load-bearing capabilities of the slipper can be recovered to a certain extent within a short period when early wear occurs, and its surface performance shows the variation characteristics of deterioration-repair-re-deterioration-re-repair.

TO THE MODERNIZATION OF HYDRAULIC FLUID POWER OF WHEEL EARTH MACHINE BASED ON HTZ TRACTORS

The purpose of the article is to scientifically search for the possibility of replacing mechanical drives of a chain working body and a rotary soil thrower of an earth-moving trenching machine with a hydraulic fluid power in order to increase reliability and effective protection against overloads.Studies have been carried out on the load characteristics of earth-moving machines of the PZM-2 (3) type and an assessment of the possibility of replacing the rotation of the chain working body and the rotary thrower of the dumped soil with the selection of hydraulic motors and pumps for a hydraulic fluid power. Hydraulic actuators must provide operation during the starting mode, minimal power loss during idling and effective protection in the event of a sudden stop of thehydraulic motors due to overloads.As a result of the calculations, it was found that for the hydraulic fluid power of the chain working body earthmoving trencher, high-torque low-speed radial piston hydraulic motors of single or multiple action with a working volume of 1800 ... 2500 cm3, as well as high-speed axial piston hydraulic motors with planetary gearboxes, for a rotary thrower of dumped soil, gerotor hydraulic motors with a working volume of about 200 cm3. The hydraulic motors required by the workingvolume are mass-produced by a number of foreign companies. To supply the working fluid to the hydraulic motors, axial piston tandem pumps with adjustable displacement, which are produced by the Hydrosila plant, are recommended.The results of the research can be used in the development of a new generation of earth-moving trenching machines when replacing the mechanical drive of the chain working body and the thrower of the dump soil with a hydraulic fluid power.

Recent Advances of Flow Rate Simulation in Gear Pumps

The gear pump is a rotating pump that moves and changes depending on the working volume that is created between the gear and the pump cylinder to transport or pressurize the liquid. It is one of the most widely used hydraulic pumping devices. It has been adopted in road equipment, conveyor systems, and other industrial machineries. Its performance is critical to the engineering equipment. With the development of fluid mechanics, the computational fluid dynamic (CFD) technique is widely used to predict the internal flow filed of gear pumps. CFD can provide researchers more intuitive observation and analysis to help the designers to enhance the effectiveness of gear pump. This paper summarizes the principle of flow simulation methods for gear pump and its applications. The research results and key findings are summarized. Defects of existing research are pointed out and suggestions for future research are provided. To sum up, this paper has a certain reference value for researchers who would like to know the hydraulic simulation process for gear pumps.

Failure Analysis and Intelligent Identification of Critical Friction Pairs of an Axial Piston Pump

Hydraulic axial piston pumps are the power source of fluid power systems and have important applications in many fields. They have a compact structure, high efficiency, large transmission power, and excellent flow variable performance. However, the crucial components of pumps easily suffer from different faults. It is therefore important to investigate a precise fault identification method to maintain reliability of the system. The use of deep models in feature learning, data mining, automatic identification, and classification has led to the development of novel fault diagnosis methods. In this research, typical faults and wears of the important friction pairs of piston pumps were analyzed. Different working conditions were considered by monitoring outlet pressure signals. To overcome the low efficiency and time-consuming nature of traditional manual parameter tuning, the Bayesian algorithm was introduced for adaptive optimization of an established deep learning model. The proposed method can explore potential fault feature information from the signals and adaptively identify the main fault types. The average diagnostic accuracy was found to reach up to 100%, indicating the ability of the method to detect typical faults of axial piston pumps with high precision.

Theoretical and Experimental Flow Characteristics of a Large-Scale Annular Channel in Terms of Deformation Gradient, Eccentricity, and Water Compressibility

Hydraulic water plunger pumps have come to be widely used in coal mining, seawater desalination, and oil exploitation due to their high output pressure and large flow characteristics. In a high-pressure large-flow plunger pump, the leakage of the annular channel of the plunger pair is an essential factor affecting volume efficiency. The axial pressure gradient exists in the fluid inside the annular channel, resulting in the plunger and plunger sleeve forming similar funnel-like shapes. Moreover, the characteristics of large diameter, high working pressure, and low fluid viscosity of the plunger pump will lead to the complicated flow of the annular channel. The influence of eccentricity and structural deformation on leakage is difficult to evaluate. Therefore, considering the deformation gradient and eccentricity of the plunger pair and the compressibility of the water, the deformation equations and leakage equations of the annular channel under the laminar and turbulent flow state are derived in this study. The eccentricity and leakage of the annular channel under different pressure conditions are measured using a built sealing test bench. It is proved that the discrepancy between the calculated model and the experimental results is less than 6% under different pressures, which effectively predicts the sealing performance of plunger pumps. The results show that under the laminar flow condition, the effects of eccentricity, structural deformation, and medium compressibility on leakage are 148%, 4.92%, and 0.92%, respectively. In turbulent conditions, they were 31%, 2.84%, and 1.19%, respectively. Besides, the reasonable material pairing of the plunger friction pair can reduce the variation of leakage due to structural deformation.

Characteristics of Various Losses of Axial Piston Pump and Bent Axis Hydro-motor with respect to Displacement Conditions and Load Demands

The hydrostatic transmission is one of the most important applications in the fluid power systems. It gives smooth change in output speed, torque and power as per the design requirements. Present article deals with various losses of the hydraulic pump and motor using a closed circuit hydraulic drive. The drive basically consists of a variable displacement axial piston pump that supplies pressurized fluid to a variable displacement bent axis hydro-motor. In investigating the pump/motor performance, bond graph simulation technique is used to model the drive system. Various losses of the pump and motor are accounted in the model by suitable resistive elements. The characteristics of them are identified through experiments. The predicted performance of the pump/motor is studied with respect to the displacement and load at the same time they are validated experimentally. The investigation made in the article identifies the control strategy which will be useful for the practicing engineers to select best combination of the pump and motor displacement for optimizing the drive performance and minimizing the losses as well. The study performed in this research work will be useful for the similar hydraulic configuration used in mobile equipment.

A Novel Fault Diagnosis Method Based on SWT and VGG-LSTM Model for Hydraulic Axial Piston Pump

Since the hydraulic axial piston pump is the engine that drives hydraulic transmission systems, it is widely utilized in aerospace, marine equipment, civil engineering, and mechanical engineering. Operating safely and dependably is crucial, and failure poses a major risk. Hydraulic axial piston pump malfunctions are characterized by internal concealment, challenging self-adaptive feature extraction, and blatant timing of fault signals. By completely integrating the time-frequency feature conversion capability of synchrosqueezing wavelet transform (SWT), the feature extraction capability of VGG11, as well as the feature memory capability of the long short-term memory (LSTM) model, a novel intelligent fault identification method is proposed in this paper. First, the status data are transformed into two dimensions in terms of time and frequency by using SWT. Second, the depth features of the time–frequency map are obtained and dimensionality reduction is carried out by using the deep feature mining capability of VGG11. Third, LSTM is added to provide the damage identification model for long-term memory capabilities. The Softmax layer is utilized for the intelligent evaluation of various damage patterns and health state. The proposed method is utilized to identify and diagnose five typical states, including normal state, swash plate wear, sliding slipper wear, loose slipper, and center spring failure, based on the externally observed vibration signals of a hydraulic axial piston pump. The results indicate that the average test accuracy for five typical state signals reaches 99.43%, the standard deviation is 0.0011, and the average test duration is 2.675 s. The integrated model exhibits improved all-around performance when compared to LSTM, LeNet-5, AlexNet, VGG11, and other typical models. The proposed method is validated to be efficient and accurate for the intelligent identification of common defects of hydraulic axial piston pumps.

КОМПЛЕКСНИЙ СПОСІБ ФОРМУВАННЯ СПРЯЖЕНИХ КРИВОЛІНІЙНИХ ПОВЕРХОНЬ

This article discusses the development of a complex method for processing helical curved surfaces of the cutting tool of a worm cutter for processing the working bodies of hydraulic pumps. Helical curved surfaces with a large angle of elevation of the turns are considered and new methods of profiling are created. A complex geometric method for solving kinematic issues related to determining the characteristics of a curvilinear surface characteristic in conjugated screw elements of hydraulic pumps is presented. The complex solution of such problems is a certain scientific problem, the solution of which is undoubtedly of great importance for the development of a complex screw cutting tool. As a result of traditionally designed screw cutting tools, the effect of chance prevails, and in the process, as a rule, defects occur in the processing of the helical surface of the screws, which reduces their service life. The solution of this problem will reduce the design time for the mating curved surfaces of the propellers and provide the necessary computational and graphical accuracy. When studying a complex method for designing helical conjugated curved surfaces, it was found that the existing methods are not enough in practice in production and have limitations in terms of design requirements. Therefore, for the manufacture of a conjugated curved helical surface of the cutting tool with technological accuracy, parameters are set with given conditions for the manufacture of hydraulic pump screws. The proposed geometric complex method for determining the characteristics of the curved helical surface of the cutting tool, namely the worm cutter, will allow designing and manufacturing automatically with maximum accuracy the conjugated curved surfaces of hydraulic pumps. Keywords: complex method, curved surfaces, kinematic screw, mating surfaces, worm cutter, hydraulic pumps, screws, characteristics, cutting tool.

Mathematical Model with Pressure Constraints to Minimize Electric Energy Costs in the Operation of Hydraulic Pumps

Water supply systems are responsible for providing quality water to the population in sufficient quantity. As sanitation companies are major energy consumers of electrical power, they have a contract of power in which the cost of electricity varies according to the period of the day. Thus, for these companies, at peak times the price of electricity is much higher. Most of the expenditure on electricity in water supply systems is due to hydraulic pumps, which are activated when the level of the tanks reaches the minimum level and remain on until the maximum levels are reached, without taking into account the time where this operation is performed. This work proposes a mathematical model for the optimization of electricity costs in water supply systems through the planning of the operation of hydraulic pumps. Numerical tests were performed through the implementation of the proposed model in GAMS software and solved by the CPLEX optimization package for different demand scenarios, in order to validate the proposed model. A model that simulates the operation performed in the practice of water supply systems is also presented, and its results are compared to the proposed optimization model. The obtained results proof of the efficiency of hydraulic pumps operation planning provided by the proposed model in relation to the operation performed in practice in water supply systems.