Hydraulic Oil Research Articles

The Mechanical Behavior of Taper Pipe Threads by Three-dimensional Finite Element Analysis

Taper pipe threads are widely used as fastening parts for connecting pipes through which water, gas, hydraulic oil, etc. flow. It is also widely used in underground conduit facilities to protect underground communication cables from external loads and fluids. One of its characteristics is its high tightness, but there have been reports of leaks and damage due to strong external forces and repeated loads at the time of earthquakes and under even normal use conditions. However, since the mechanical behavior of tapered pipe screws is more complicated than that of ordinary fastening bolts, it is difficult to perform a highly accurate analysis. Therefore, in this study, in order to clarify the mechanical behavior of taper pipe threads, we created a three-dimensional analysis model of hexahedral elements that faithfully reproduces the shape of taper pipe threads, and quantitatively evaluated the effects of parameters such as pipe thickness, coefficient of friction, and number of screwing threads on resistance to external forces. The purpose is to clarify the mechanical properties systematically, and we have elucidated the trends of the parameters on the stress amplitude in three different cyclic load modes.

Experimental and Simulational Study on Cavitation Flow in Control Valve at Different Hydraulic Oil Temperatures

Experimental and Simulational Study on Cavitation Flow in Control Valve at Different Hydraulic Oil Temperatures

The Influence of Wave Processes of Hydraulic Oils on the Operation of a Hydraulic Drive

Abstract The paper reviews the state of research of wave processes in hydraulic systems of machines, and their impact on the quality and stability of hydraulic drives. As noted in the works of previous researchers, these phenomena occur in hydraulic systems and adversely affect the quality and stability of their work, significantly reducing reliability. The method of construction of mathematical models is offered. A mathematical model of the hydraulic system with two series-connected hydraulic motors is built, taking into account transients. The Runge-Kutta-Feldberg method with automatic change of the integration step was used to solve this model. The application of this method makes it possible to estimate the amplitude and frequency of the pressure wave in real time for each part of the pipeline. As a result of the analysis of the obtained transients it was concluded that at the length of the pressure line in a group hydraulic drive with 2 series-connected hydraulic motors up to 1.5 m, wave processes do not significantly affect the system and in the mathematical model they can be ignored. With the length of the pressure line from 1.5 m to 9 m, the wave processes in the cavity do not affect the stability of the system, although significantly impair the quality of its work. Hydraulic systems with a pressure line length of more than 9 m are not recommended for implementation, because the wave processes in the cavity lead to vibrations and noise in the hydraulic system and require additional measures to eliminate the impact of this phenomenon.

Mechanism of Inbuilt Automatic Hydraulic Jack used for Light and Heavy Vehicles

Abstract: This paper is about the new automatic technique of inbuilt hydraulic jack system. Whenever the tire failure is occurred in the vehicle then to lifting the vehicle from ground surface is the very difficult think for human being and also, huge human effort required and more time taking process. There, this inbuilt hydraulic jack system helps to lift the vehicle from the ground instead of conventional mechanical jack, and saves the time and excess effort. Separate buttons are provided in order to raise or lower the right and left side jacks. By pushing the given button in the dashboard, the inbuilt self-jacking component gets initiated. Main parts of this project are hydraulic jack, master cylinder, valves, manifold, and oil reservoir. The inbuilt hydraulic jack will be valuable to the senior residents and for women who discover it incredibly hard to work the jack physically in any breakdown of the vehicle. This hydraulic jack will have the option to lift the wheels as indicated by our prerequisite that is on the off chance that we need to lift just two wheels, at that point it tends to be finished by moving the cylinder as needs be on the rack with the assistance of the DC motor. Index Terms: Hydraulic Jack, Master Cylinder, Incompressible Hydraulic Oil, Pascal’s Law

Bench Testing of Sensors Utilized for In-Line Monitoring of Lubricants and Hydraulic Fluids Properties

This work reports the results of a study on the behaviour of five sensors recently developed for oil conditions monitoring, installed in-line in an experimental test rig for lubricants. The tests were carried out on seven oils of different origins (one synthetic ester, two bio-based synthetic esters, four vegetable oils) and use (two UTTOs and five hydraulic oils), under controlled working conditions, according to a specially designed test method. At first, the study concerned the identification of the conditions for the correct sensors’ installation. Then, the tests started applying to the fluids severe work cycles intended to accelerate oil ageing. The data of viscosity, permittivity, relative humidity, electric conductivity, particle contamination, and ferro-magnetic particles provided by the sensors were compared to the results of laboratory analyses made on oil samples taken during the tests with the aim of verifying the sensors measurements accuracy and reliability and selecting the more suitable ones to in-line oil conditions monitoring, in the perspective of introducing them also in field applications, e.g., on agricultural tractors, for preventing damages due to oil deterioration, and in managing the machine maintenance.

Dynamics of hybrid nanofluid through a semi spherical porous fin with internal heat generation

Semi-spherical fins are widely considered to be one of the best thermal exchangers available. It is widely employed, including aero planes, chemicals and electronic kits and porous medium is an extensive application that includes drying efficiency enhancement, filtering insulations, hydraulic oils, reactor temperature control and solar collectors. With these applications in perspective, the current study uses Darcy’s model to examine the performance of hybrid nanofluids flowing over a semi-spherical porous fin. Additionally, temperature dependent internal heat generating condition, natural convection and radiation effects are also taken into account. The nonlinear form of an ordinary differential equation (ODE) along with boundary conditions is resolved using RKF 45 method. The numerical results are obtained for various physical constraints and the impact of these constraints on fin surface temperature is discussed via graphs. The results show that increasing an internal heat generation parameter raises temperature, whereas the opposite is true for radiation and convective parameters. Furthermore, the temperature of the hybrid nanofluid is consistently higher than the temperature of the nanofluid.

Effect of Temperature on the Tribological Properties of Selected Thermoplastic Materials Cooperating with Aluminium Alloy.

This article concerns the tribological properties of three selected polymer materials: polyamide PA6, polyethylene PE-HD and polyetheretherketone composite PEEK/BG during sliding against aluminium alloy EN AW-2017A in the presence of hydraulic oil HLP 68. The tests were carried out under contact pressure p of 3.5–11 MPa at ambient temperature T ranging from −20 °C to +20 °C. The dependence of kinetic friction coefficient μk on the two parameters was determined through tribological tests carried out using a pin-on-disc tribometer. A five-level central composite rotatable design (CCRD) was adopted for the experiment. All the test results were statistically analysed. The microhardness of the surface of the polymeric material was measured before and after the friction process. The surface was also examined under SEM. Temperature and contact pressure have been found to have a significant effect on the tribological properties of the tested sliding pairs. Relative to the applied friction conditions, the surfaces after friction showed rather heavy signs of wear.

An Impedance Sensor for Distinguishing Multi-Contaminants in Hydraulic Oil of Offshore Machinery.

The cleanliness of hydraulic oil can reflect the service life of the oil and the wear state of hydraulic machinery. An impedance sensor is proposed to distinguish multi-contaminants in hydraulic oil. The impedance sensor has two detection modes: the inductance-resistance mode is used to detect metal debris, and the capacitance mode is used to distinguish water droplets and air bubbles. By adding a built-in silicon steel strip and an external silicon steel strip with high magnetic permeability, the distribution area, strength, and uniformity of the magnetic field are enhanced to improve the detection sensitivity under inductance and resistance parameters. In addition, the silicon steel strips are used as electrode plates to introduce capacitance parameter detection. The experimental results show that the resistance detection method based on coil successfully improves the detection ability for non-ferromagnetic metal debris. The impedance sensor for distinguishing multi-contaminants in hydraulic oil can provide technical support for fault diagnosis of offshore hydraulic machinery.

Researches concerning the hydraulic oil degradation process in gear pumps

Researches concerning the hydraulic oil degradation process in gear pumps

Evaluation of effect of oil viscosity in MQL turning of aluminium 6061

Minimum Quantity Lubrication is an appropriate choice for machining since it is cleaner and more sustainable compared to conventional coolants. In this study, the performance of different oils in the turning of aluminium 6061 with minimal quantity lubrication (MQL) is compared to machining under dry circumstances. The MQL condition was studied using vegetable oil and hydraulic oil. Cutting speed, feed rate, and depth of cut (D.O.C.) are all changed in the experiment, and two values of each parameter are utilised. For the study, authors evaluated cutting performance in terms of force component (Fx,Fy, Fz) and Surface Roughness (Rc) along with chip shapes. The results show that the MQL utilizing vegetable and hydraulic oils produces a higher surface finish. Based on the outcomes. The MQL condition outperformed the others.

Can a compact biological system be used for real hydraulic fracturing wastewater treatment?

Hydraulic fracturing wastewater (HFW), a byproduct of hydraulic fracturing oil extraction, contains a complex mixture of oil, aldehydes, and benzene compounds. Efficient and eco-friendly HFW treatment means are critical for the oil extraction industry, particularly in developing countries. In this study, two biological processes namely an anaerobic/anoxic/moving bed biofilm reactor (A2-MBBR) and an A2-MBBR with a microfiltration membrane (A2-MFMBBR) were established, and assessed for the real HFW treatment. Removal efficiencies of chemical oxygen demand (COD) and NH4+-N were over 92% and 95%, respectively, in both processes with a hydraulic retention time of 72 h. The majority of organic compounds in both systems identified by GC–MS were degraded in the anaerobic units. In comparison, A2-MFMBBR demonstrated higher removal efficiencies for oil, total suspended solids, and complex compounds. The average relative abundances of refractory compound degrading bacteria were 43.4% and 51.6% in the A2-MBBR and A2-MFMBBR, respectively, which was consistent with the COD and oil removal, and suggested that the MBR could maintain a high diversity of microorganisms and contribute to deep recalcitrant organics degradation. This study sheds light on the potential of using a compact biological process for the real HFW treatment.

The importance of the electrical properties of hydraulic fluids

PurposeApart from the basic material properties of liquid lubricants, such as, e.g., the viscosity and density of the hydraulic fluid, it is also important to have information regarding the electrical properties of the fluid used. The latter is closely related to the purpose, type, structure, and conditions of use of a hydraulic system, especially the powertrain design and fluid condition monitoring. The insulating capacity of the hydraulic fluid is important in cases where the electric motor of the pump is immersed in the fluid. In other cases, on the basis of changing the electrical conductive properties of the hydraulic fluid, we can refer its condition, and, on this basis, the degree of degradation.Design/methodology/approachThe paper first highlights the importance of knowing the electrical properties of hydraulic fluids and then aims to compare these properties, such as the breakdown voltage of commonly used hydraulic mineral oils and newer ionic fluids suitable for use as hydraulic fluids.FindingsKnowledge of this property is crucial for the design approach of modern hydraulic compact power packs. In the following, the emphasis is on the more advanced use of known electrical quantities, such as electrical conductivity and the dielectric constant of a liquid.Originality/valueBased on the changes in these quantities, we have the possibility of real-time monitoring the hydraulic fluid condition, on the basis of which we judge the degree of fluid degradation and its suitability for further use.

Performance Analysis of the Swashplate Axial Piston Pump with Hydraulic<br /> Fluid Temperatures

T Variable displacement axial piston pump can be used in a hydraulic system as the primary source of fluid power, which is suitable for high pressure and high efficiency. The power can be transfer in a hydraulic system with the help of the fluid medium. The oil leakage problem in various parts of the pump, especially the internal leakages in the piston-cylinder, swash plate-slipper pad and valve plate-cylinder block, seriously affect the performance of the pump. Therefore, it is important to know the properties of the fluid and its effect on the system performance. To study the performance of an axial piston pump, a non-linear mathematical model has been developed. The developed model has been validated with the existing results. The validated pump model has been used for performance analysis of the system. Moreover, the influence of hydraulic mineral oil at different temperatures on the piston chamber pressure, output power, and leakage flow in piston-cylinder has been explored. The present investigation has been performed in MATLAB Simulink 14a environment. The simulation result shows that the pump operating temperature range can be set as 30℃ to 60℃ for moderate ripple and output chamber pressure.

Propagation Characteristics of Pressure Pulsation in Hydraulic Hose

Most modern aircraft hydraulic systems use variable plunger pumps. The pulsating flow output is its inherent characteristic. The resulting pressure pulsation often causes serious damage to the energy pipeline system and endangers the lives of the occupants. This paper studies the propagation law of hydraulic oil in hydraulic hoses, fully considers the coupling vibration of hydraulic oil high-pressure fluid and flexible solids of the hose, establishes a fluid-solid coupling vibration model of hydraulic hoses, and uses ANSYS for numerical simulation to study different frequencies and pipe bending. Using ANSYS for numerical simulation to study the influence of different frequencies and pipe bending radii on the amplitude of fluid pressure pulsation, after comparative analysis, the law of fluid pressure pulsation propagation in hydraulic hoses is obtained.

Research on Evaluation Technology of Low Temperature Cold Start Performance of Hydraulic Oil

In order to comprehensively test the low temperature cold start performance of hydraulic oil and ensure their use effectiveness to the fullest, the idea of low temperature cold start performance index is proposed, so as to comprehensively evaluate the low temperature capability. Firstly, the cold start performance index system of hydraulic oil tested in low temperature environment is constructed, so as to describe its low temperature capability from multiple angles and in a comprehensive manner; secondly, for different index types, the corresponding data collection methods and data analysis methods are clarified, and the low temperature cold start performance of hydraulic fluid is evaluated. Finally, using the method as an example for three oils, the index types and assessment results are given to further illustrate the scientific nature of the research method. The research content can provide some technical support for the evaluation of the low temperature cold starting performance test of hydraulic winches.

CFD Simulation of Kaplan Turbine Rotating Union and the Development of a Real Time Diagnostic System

Obtaining energy from low-emission sources is extremely important currently. The use of hydropower plants for electrical energy production proves to be advantageous. The most commonly used type of water turbines are Kaplan machines due to the highest efficiency they offer in a wide range of operation. There is a need to increase the reliability of operating machines due to the failure of the oil heads performing the task of supplying hydraulic oil to the interior of the rotating turbine shaft to control the Kaplan turbine rotor blades. An in-depth analysis of physical phenomena such as friction, mechanical vibrations, and heat transfer has been carried out. The assumptions for the construction of the FDHC early diagnostics system have been created. Methods of measuring the parameters have been defined, which have consequently assisted in creating an algorithm for the testing method of a working machine in real time. The 3D CFD simulation method has been applied and physical phenomena have also been implemented in order to enable the reconstruction of the actual processes taking place inside the working element. This has enabled the observation of changes in physical quantities in any cross-section and point of the component tested. These activities have made it possible to determine the critical measurement points of physical quantities in the model that can be applied to a real object. In order to confirm the correctness of the assumptions made for the construction of the FDHC system, the 3D CFD simulation has been compared with the results obtained during measurements carried out on a working hydro unit. The results of the measurements carried out with the thermal imaging camera have partly coincided with the results obtained in the computational model.

Weight and performance optimization of rectangular staggered fins heat exchangers for miniaturized hydraulic power units using genetic algorithm

The compact, lightweight, and energy-efficient heat exchanger is significant for the miniaturization of hydraulic power unit in quadruped robot. In this work, a rectangular staggered fins heat exchanger (RSFHE) as an ideal lightweight heat exchanger for miniaturized hydraulic power units is investigated and optimized based on the experimental correlations of heat transfer and flow resistance for the fluids with different Prandtl number. Function models including the related mass, outlet temperature and pressure drop are defined. A sensitivity analysis is presented to investigate the effect of key parameters on function models, which can evaluate the contributions of variables to the comprehensive performance of the heat exchanger. Based on these function models, the heat exchanger key parameters are optimized using genetic algorithm (GA). Moreover, numerical simulations are conducted to explore the thermal-hydraulic performance of the original and optimized heat exchangers and the simulation results are almost equal to the theoretical results calculated by experimental correlations. Compared with the original heat exchanger, the total weight of the optimized exchanger reduces by 25.49% and its heat transfer capacity increases by 24.22% taking the inlet-outlet temperature difference of the hydraulic oil as the index, which is a great improvement for the miniaturization and lightweight of the hydraulic power unit.

Pipeline Pressure Loss in Deep-Sea Hydraulic Systems Considering Pressure-Dependent Viscosity Change of Hydraulic Oil

The high ambient pressure in deep-sea conditions greatly increases the viscosity of hydraulic oil and then the pipeline pressure loss in deep-sea hydraulic systems. Large pipeline pressure loss can lead to a further change of viscosity on the basis of the viscosity increase caused by the ambient pressure when the hydraulic oil flows through the pipeline. Therefore, the classic Poiseuille’s law can no longer accurately calculate the pipeline pressure loss in deep-sea conditions since it treats the viscosity as a constant. In this paper, based on laminar flow theory and the viscosity-pressure characteristics of hydraulic oil, a novel equation for pipeline pressure loss is proposed, in which the viscosity change when flowing through the pipeline is taken into account. A CFD (Computational Fluid Dynamics) model of a pipeline in the deep-sea hydraulic system has been established, and CFD simulations have been conducted to verify the correctness of the proposed equation for pipeline pressure loss. Theoretical analysis shows that the proposed novel equation for pipeline pressure loss is equivalent to the classic Poiseuille’s law when the pipeline pressure loss or the viscosity change is low. The research results in this paper can provide theoretical support for work efficiency optimization, load capacity improvement, and precise control of deep-sea operation equipment or deep-sea hydraulic systems.

Development of the measurement procedure and certified reference material of water mass fraction in a mineral oil

The necessity of developing certified reference materials (CRM) for the composition of mineral oil with a certified value of the mass fraction of water, traceable to the State Primary Standard of units of mass fraction and mass (molar) concentration of water in solid and liquid substances and materials GET 173–2017 is revealed proceeding from the review of standardized methods for determining the quality of mineral oils and approved types of reference materials (CRMs). Mineral hydraulic oil MIL-H-5606 of CONOSTAN series manufactured by SCP SCIENCE (Canada) was chosen as the CRM material to control the accuracy of the results of water determination in mineral oils using IR spectrometers. A procedure for reproducing the mass fraction of water in a mineral oil using a standard installation based on coulometric titration according to Karl Fischer method from the composition of GET 173–2017 has been developed. The relative expanded uncertainty (atk= 2) of measurement results of the water mass fraction in mineral oil is 7.1%. The requirements to the metrological characteristics of CRM were formulated: the interval of permissible certified values, the limits of the permissible values of the absolute error atP= 0.95, and the permissible value of the absolute expanded uncertainty atk= 2. The choice of the method of packaging and conditions of CRM storage were analyzed. Taking into account the consistency of the measurement results of the water mass fraction obtained by coulometric titration according to Karl Fischer method and using a Fluid Scan infrared spectrometer manufactured by Spectro Inc., USA, the applicability of CRMs for metrological support of express IR spectrometers was demonstrated.

Development and application of triaxial rock shear - self-supporting fracture conductivity experiment system

The structure and function of shear - self-supporting fracture conductivity test device in great detail were presented. This device system consists of five parts: vertical loading system, horizontal shear loading system, the servo control system, power system, shear box and its sealing system, digital control and acquisition system. It can provide vertical force up to 2000KN, shear force 500KN, lateral stress 50MPa and hydraulic pressure 40 MPa. Characteristics of the system are illustrated as follows. (1) The experimental research of rock shear failure can be performed under three axial stress conditions, the lateral stress is loaded by hydraulic oil and the vertical stress is loaded by pressing machine. (2) True triaxial and quasi-triaxial loading modes can be switched by using different sealing sleeves. (3) The shear seepage coupling and self-supporting fracture conductivity tests could be conducted under three axial stress conditions. (4) The stress and displacement loading modes under different loading rate can be realized by servo system. Based on this experimental system, shear - fracture conductivity test under three axial stress conditions was performed on shale specimen and its reliability was verified. The experimental system can be used to provide theoretical basis for the shear destruction mechanism and Self-supporting shear fracture conductivity test under true triaxial stress conditions. The research has an important guiding significance on the formation mechanism of unconventional reservoir shear fracture and the flow capacity of self-supporting shear fracture and its influencing factors.