Hydraulic Test Bench Research Articles

Fault diagnosis in a hydraulic directional valve using a two-stage multi-sensor information fusion

As it is usually operating in bad working conditions and subjected to the severe interference from diverse paths, internal faults of the hydraulic valve are difficult to be detected using conventional hydraulic testing technology (such as relying on pressure sensors or flow sensors). Moreover, the information collected from a single sensor may not provide accurate diagnostic evidence or a complete description on faults of hydraulic valves, even though employing intelligent fault diagnosis methods. Therefore, a two-stage multi-sensor information fusion method is proposed, including the fault feature fusion and the decision-making information fusion. The aim is to realize the diagnosis on internal faults of hydraulic directional valves using the vibration signal analysis method instead of conventional hydraulic testing ones. The method is mainly divided into three steps. First, the noise reduction of the vibration information collected by multiple acceleration sensors is done using ensemble empirical mode decomposition (EEMD) and Teager-Kaiser energy operator (TEO), so that fault features are more obvious. Then, multi-class fault features including the severity and the location of the wear are extracted from the preprocessing signals to form the original feature set. Second, combined with feature ranking and subset selection based on euclidean distance (FRSSED) and maximum relevance minimum redundancy (mRMR) feature selection method, the statistical features extracted from multiple sensor signals are optimized to form the optimal feature subset. This is the first-level information fusion concerned with fault feature information fusion. In the third step, based on Dempster-Shafer (DS) evidence theory and convolutional neural network (CNN), decision-making information is fused (called second-level information fusion) to obtain the final diagnosis results. A hydraulic test bench is built to test different failure valves. Experimental results indicate that this method is effective in extracting the fault features from multi-sensor signals and detecting the fault states including severity and location of internal wear of the hydraulic valve.

Dynamic performance investigation on the hydraulic-suspended passive shutdown subassembly of SFR

Hydraulic suspended passive shutdown subassembly (HS-PSS) belongs to one of the diverse passive safety devices for further enhance safety for pool-type sodium-cooled fast reactor (SFR). The hydraulic moving body (HMB) in the PSS with neutron absorbers inside was designed to insert into the core automatically within a stipulated time when the mainstream below a critical flow rate. The dynamic displacement performance of the HMB is of particular importance to ensure the safety of SFR especially during the Unprotected loss of flow accident (ULOF). In this paper, the mathematical modeling related to the falling process, the hydraulic characteristics of HMB under different flows are detailed. A series result of the sensitivity analysis of the factors affecting HMB performance, such as the flow rate and the size of some key structures, are obtained through calculation. A PSS-mockup was tested at the hydraulic (water) test bench and the calculation program was validated by the experimental results.

Modeling the warm-up process for hydraulic actuator components

This paper discusses warm-up processes for the hydraulic system components of road construction machinery using mathematical and physical simulations. The efficiency of these processes is governed by warm-up and cool-down rates of the hydraulic actuator components. It studies how various hydraulic system components interface as they warm up. The general task is to estimate the dynamic behavior of the components and loops comprising such components and the entire warm-upsystem. The models of the transient heat flow process of the warm-up system are based on the heat balance equation of the flowing medium (of the heat transfer fluid – a hydraulic fluid) within the control volume. For experimental verification, the hydraulic actuator components warm-up modes using the warmed-up hydraulic fluid from the hydraulic tank have been tested on the hydraulic test bench that we developed. The example of consecutive warm-up of the hydraulic system components is given. Based on this, after the experimental findings were processed, correlation coefficients for different warm-up modes and types of relationships between the hydraulic actuator component temperatures and their warm-up times were determined.

Design and research of hydraulic screed test bench

In order to meet the requirements of the performance test of the screed, a hydraulic test bench for screed is designed, which realizes the action of the screed. On this basis, the test bench measurement and control software based on LabVIEW is developed, it completes the tests and data analysis of screed. The test results show that the system has perfect functions and meets the requirements of screed test.

Establishment of Hydraulic Turbine Test Bench on the Tibet Plateau

There are abundant water resources in Tibet plateau area. With the increasing demand for electric power, it is necessary to build hydropower stations and test bench in Tibet Plateau area. The low air pressure has an influence on the flow in the hydraulic turbine. Therefore, a hydraulic turbine test bench is designed and built in the Tibet Plateau for low pressure hydraulic turbine experiment. The laboratory building is a three-storey structure with one distribution room and two control rooms. The civil structure is designed according to the layout of two test bench. The built underground storage tank has an area of 300 m2, a 15-meter high water tower and a capacity of 50 m3, which can meet the requirements of simultaneous operation of the two test bench The maximum head of the main pump is 30 meters, the rated power of the main motor is 160 kW, and the rated power of the dynamometer is 110 kW, which can be operated in both positive and negative directions. Meanwhile, a set of measurement and control system software is designed to acquire experimental data. The test bench will meet the needs of experimental teaching and scientific research of hydraulic turbines in Plateau area, and meet the performance comparison and acceptance test of medium and small hydro-machinery.

Oil film characteristics and flow field analysis of asymmetrical hydrostatic support structure with full hydraulic fixed-length shear servo cylinder

The heavy-duty servo cylinder is the main actuator of the full-hydraulic fixed-length shear. The cylinder requires horizontal articulated mounting for accurate curve forces. The output of the curvilinear force causes the piston rod to be subjected to a dynamic bias load, and the presence of the bias load adversely affects the servo cylinder seal structure. In this paper, an asymmetric hydrostatic support structure is designed in the guide sleeve for the bias load problem of the servo cylinder, and the anti-offset capacity of the structure is theoretically studied. The oil film characteristics and oil film stiffness of the structure are deduced and analyzed. Fluent software is used to simulate, and then analyze the influence of inlet pressure, piston rod speed, eccentricity and partial load on the performance of asymmetric static pressure bearing oil film. Asymmetrical hydrostatic support structure servo hydraulic cylinder test bench is built for anti-bias load performance and friction performance experiments. The research results show that the new asymmetric hydrostatic support structure has a good effect on balancing the dynamic partial load, effectively reducing the friction of the servo cylinder and making the automatic alignment of the piston rod and the guide sleeve, which proves that the technology can be effective, increase the service life of the servo hydraulic cylinder and then improve the overall efficiency of the full hydraulic dividing shear, while broaden the application field of the heavy duty servo cylinder.

Design of a High Performance Hydraulic Valve Comprehensive Test Bench

Design of a High Performance Hydraulic Valve Comprehensive Test Bench

Design of automatic in and out device of hydraulic support test bench

Design of automatic in and out device of hydraulic support test bench

Planta Piloto de Bombas Hidráulicas para la Enseñanza y Aprendizaje de la Mecánica de Fluidos

Este trabajo fue desarrollado con el propósito de fabricar un banco de pruebas de bombas hidráulicas portátil para aplicaciones didácticas para así estudiar el flujo de fluidos y sus características en el cual pudo desarrollar experiencias prácticas en el área de ingeniería, conociendo así como se maneja en el ámbito laboral e industrial el comportamiento de este, Por lo tanto este trabajo desarrollado fue sustentado por teorías de Bombas, Teoría, Diseño y aplicaciones, Maxtais (2009), Ciencia de los materiales, Smith (2001), Resistencia de los Materiales, Mott (2009), Introducción a la Ingeniería, White (2011). Por otra parte, la presente investigación se encontró en la modalidad de proyecto de tipo factible por consiguiente se usó la técnica de recolección de datos, como el manejo de técnicas de estadísticas, observación directa, entre otras. Finalmente, se realizaron procedimientos prácticos para la construcción de la planta piloto, como la de parametrización del diseño del mismo, la selección tanto de materiales como equipos, al igual que el diseño de este plasmado en planos acotados con la utilización de AutoCAD 2015 ®, desarrollando de esta forma las 5 etapas u fases de la fabricación de esta herramienta de estudio las cuales fueron validada por razón de la presión de operación, desempeño, cabezal y robustez de este.

Design of Remote Hydraulic Teaching System

In this paper, a set of remote hydraulic teaching experiment system is designed and developed based on the demand of teaching experiment of hydraulic related courses in colleges and universities, which can enable teachers or students to conduct experiment operation on the field hydraulic testing platform at the remote client, so as to facilitate teachers and students to carry out hydraulic teaching experiment and research. The main contents of this paper are as follows: according to the requirements of hydraulic servo control system related to the teaching experiment, the experimental project of remote hydraulic teaching experiment system is determined. Through the analysis and comparison of C/S and B/S software system architectures, the remote monitoring scheme based on B/S mode is determined. Completed the design of the hydraulic circuit of the hydraulic test bench, developed the field measurement and control system based on LabVIEW, and built the remote monitoring system based on B/S mode. The development of the remote hydraulic teaching experiment system was completed. The input signal response experiment and load characteristic experiment of the valve-controlled motor electro-hydraulic speed servo control system were carried out on the remote client to the field hydraulic experiment platform, and the experimental results were analyzed. The experimental process and results have reached the expected target and meet the demand of remote hydraulic experiment.

Implementation and Evaluation of a Sensorless, Nonlinear Stroke Controller for an Implementable, Undulating Membrane Blood Pump

In this contribution, a methodology from identification to sensorless control for a vibrating membrane pump prototype is presented and evaluated, with the objective to drive an innovative cardiac assist device. For this purpose, a model of the pump is presented to design an observer-based stroke controller that only uses current measurement. Model parameters are identified experimentally with a dedicated test bench and are used to tune the controller. The control strategy is evaluated on a hydraulic test bench.

Pressure drop in valve for different open flow areas

In any piping system different types of regulating components (valves) are used. To determine the pressure drop of the liquid in these components, it is necessary to know the exact values of the local loss coefficients, which depend on their design and manufacturer. The calculations of local loss coefficients of the valves are usually carried out according to engineering methods using design handbooks. However, the large design diversity of the valves does not allow an accurate assessment of the local loss coefficient for a particular product (using handbooks). There are two ways to solve this problem. The first way is experimental determination; the second is calculation using CFD modelling. This article presents the results of CFD simulation of the pressure drop of liquid through valves and a comparison with experimental data obtained from the thermal hydraulic test bench.

Modeling and Analysis of Maximum Power Tracking of a 600 kW Hydraulic Energy Storage Wind Turbine Test Rig

An innovative wind turbine with a particular hydraulic transmission and energy storage system is proposed in this paper. The purpose of applying the hydraulic transmission is to remove the gearbox and power converter of traditional wind turbine and cooperate on wind resource storing with the energy storage system. To overcome the volatility and intermittence shortcomings of wind and improve the output power quality, hydraulic accumulators are used as the energy storage device for wind energy regulation. The original gearbox and generator in the nacelle of a Micon 600 wind turbine were removed and replaced with a hydraulic pump to make a test rig for the investigation into maximum power point tracking (MPPT) of this hydraulic wind turbine concept. The mathematical model of the entire test system is established according to the four function modules. The MPPT control strategy based on the tip speed ratio (TSR) is adopted and a control system containing three closed-loop controls is designed to achieve maximum wind power extracting and produce constant frequency power generation. Ultimately, the dynamic response of rotor speed control is revealed under step change of wind speed and the maximum power tracking performance of the 600 kW hydraulic energy storage wind turbine test bench is simulated and analysed by subjecting to turbulent speed condition. The simulation results demonstrate that the rotor of the wind turbine can run at the expected optimal speed depending on wind speed, and the wind power utilization coefficient of the unit is stabilized at about the maximum value.

Design and experimental analysis of end face profile of tri-screw pump

This study proposes a new type of tri-screw pump, which has a 1:2:3 ratio of the active diameter of the screw, the diameter of the pitch circle, and the top diameter of the active screw. Fixed width correction method of the driven screw is also proposed to avoid wear of tooth top. The mathematical model of active and driven screws is established. To avoid the wear of the tooth top arc, several transition patterns are proposed, and the transition curve in the form of a circular arc is deduced. The designed screw curve is grinded, and the tri-screw pump is assembled. The hydraulic pump test bench is tested using the overflow valve to perform pressure loading of 3–5 MPa on the outlet of the screw pump. The outlet flow rate and pressure are tested, and results indicate that the output flow of the pump conforms to the designed flow rate. This study establishes the detailed equation of the end face profile of the tri-screw pump (active and driven screws) and corrects the arc profile of the line angle.

Test Verification of Wave-Plate Separation Element for Moisture Separator Reheater

The separation characteristics and pressure drop characteristics of the saturated wet steam through the corrugated plate separation element are verified under the actual operating conditions of the moisture separator reheater (MSR) for PWR nuclear power units. The saturated wet steam which meets the requirements are provided by using a large thermal hydraulic test bench, and the pressure drop and residual humidity are obtained when the wet steam flows through the test piece. The results show that the critical flow rate of re-entrainment is high, and when the inlet steam dryness is not greater than 86% and the inlet flowrate is less than the critical flowrate, the residual humidity is not greater than 0.1%, the separation efficiency is of 99% or more, and the pressure drop is not greater than 7 kPa. The design requirements of more than 99% steam dryness and less than 14kPa pressure drop are satisfied. It is with good separation and pressure drop characteristics.

Research and test on electrical power recovery of hydraulic motor test bench

In this paper, the working principle of a kind of hydraulic motor test bench based on electric power recovery has been described. Relationship between the pressure, speed, torque and other parameters of the test bench with the recovery rate has been tested and analyzed. According to the test, hydraulic motor test speed and test pressure have a certain impact on the system power recovery rate. By choosing appropriate test speed and pressure, greatly reduce of the power consumption of the test system and of system heat dissipation can be realized.

Possibility of Conducting Flow Structure Studies on a Large-Scale Hydraulic Test Bench

This article deals with tasks that can be performed on a large-scale hydraulic test bench. Overall dimensions of the stand are shown in Fig.1. Hydraulic test bench will carry out open flow modeling studies that will help to solve a number of tasks, for example, studying of the alluvial regime in river port conditions, as well as the impact of dredging on shipping conditions.

Numerical Simulation and Experimental Testing of Two-axle Chassis of Low-floor Trams

This paper deals with numerical simulations and with experimental testing of chassis of low-floor trams. This chassis was designed with respect to low-floor construction, low weight, good driveability of a tram and with respect to fulfillment of standards and regulations. The chassis is in a numerical simulation burdened by load conditions according to EN 13749:2011 even during an experimental testing. The simulation is performed using the FEM Nastran solver implemented in the CAD system Siemens NX 11. Based on FEA the locations for strain gauges during testing were found. A total number of 40 strain gauges were used to measure the strain which was then recalculated to uniaxial stress. The testing was performed on hydraulic test bench Inova. The results of FEA and of an experimental testing were compared.

Damping Characteristic Analysis and Experiment of Air Suspension with Auxiliary Chamber

In this paper, the damping characteristics of air suspension with auxiliary chamber are studied. A single degree of freedom nonlinear mathematical model of air suspension with auxiliary chamber was established based on theories of aerodynamics, engineering thermodynamics and fluid dynamics. Secondly, the damping characteristics are simulated by Matlab/Simulink, and the relationship of relative damping coefficient and natural frequency with the opening degree of throttle hole under different excitation amplitude were discussed, a basic control strategy for damping control of air suspension with auxiliary chamber was proposed. Finally, the relation between valve opening and driving voltage of proportional flow control valve was studied experimentally, the hydraulic vibration test bench was set up and the damping characteristics experiment of air suspension with auxiliary chamber was carried out, the nonlinear mathematical model and simulation results were also verified at the same time. The results showed that experiment and the simulation have good consistency, verifying the correctness of the established mathematical model. The research would provide a theoretical reference for how to design and control of air suspension with auxiliary chamber.

CHOICE OF THE OPTIMAL PARAMETERS OF MEASURING THE SHAFT ROTATION FREQUENCY OF THE HYDRAULIC TRANSMISSION OF THE LOCOMOTIVE USING MICROCONTROLLER

Purpose. The article provides for finding solution to the problem of developing and improving the means for measuring tachometric data of the previously created information and measuring system for testing hydraulic locomotive transmission by substantiating the optimal sensor design and signal processing algorithms. At the same time first of all it is necessary to start from the possibility of modifying the already existing test bench for hydraulic locomotive transmissions at the Dnipropetrovsk diesel locomotive repair plant «Promteplovoz». Methodology. In the work, the researchers proposed a methodology for modifying the sensor design and the algorithm for processing its signals. It is grounded on previous developments of tachometric sensor of the optical type on the basis of D-2MMU-2 sensor of the microprocessor automated test bench system of hydraulic locomotive transmission in the locomotive repair plant conditions. Selection of the necessary measurement algorithm and the number of sensor teeth is substantiated by calculating instrumental and methodological errors. Also, the studies aimed at identifying the source of interference in the measurement of rotational speed are described and solution for its elimination has been found. Findings. For the designed rotation speed sensor of the optical type based on the existing D-2MMU-2 sensor, the authors analyzed the dependence of the methodological and instrumental errors. Based on the obtained data more rational variant of the rotation speed calculation algorithm is proposed, and the number of teeth of the sensor disk is justified. Further, the main source of measurement interference was established and a method for improving the hardware of the hydraulic locomotive test bench was proposed. Originality. There were conducted the studies according to the methodological and instrumental errors of the designed rotation speed of sensor. The mechanisms of interference filtering arising from the sensor rotation speed fixing were proposed. Additional studies have shown the need for a hardware revision of signal conditioner scheme. Practical value. Conducted studies make it possible to establish a rational number of sensor disk teeth, which allows improving the measurement algorithm. It was also performed a hardware improvement of signal conditioner scheme from the sensor, helping to get rid of interferences. The results of measurements in studies are the initial data to perform further studies in order to determine the technical condition of hydraulic transmission UGP 750-1200 during factory testing after repair.