scholarly journals The importance of the electrical properties of hydraulic fluids

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Darko Lovrec ◽  
Vito Tič
Keyword(s):  
Electrical Properties ◽  
Hydraulic System ◽  
Basic Material ◽  
Hydraulic Fluid ◽  
Content Type ◽  
Mineral Oils ◽  
Ionic Fluids ◽  
Hydraulic Fluids ◽  
Conductive Properties ◽  
Degree Of Degradation

Purpose Apart 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/approach The 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. Findings Knowledge 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/value Based 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.

Ensuring the Reliability of an Aircraft Engine Hydraulic System

2014 ◽  
Vol 616 ◽  
pp. 126-134 ◽  
Author(s):  
Janka Mihalčová ◽  
Peter Šmeringai
Keyword(s):  
Hydraulic System ◽  
Kinematic Viscosity ◽  
Chemical Properties ◽  
Aircraft Engine ◽  
Hydraulic Fluid ◽  
Aircraft Engines ◽  
Ftir Analysis ◽  
Physical Chemical ◽  
Hydraulic Fluids ◽  
Degradation Degree

The article deals with the issue of ensuring the reliability of aircraft engines operation via hydraulic fluids properties monitoring. There are presented the results of the hydraulic fluid Aero Shell Fluid 41 (ASF 41) properties evaluation in the hydraulic system of a double-flow turbosupercharged aircraft engine AI-25TL. In the hydraulic fluid, there were observed the quantity and distribution of mechanical particles according to their size in accordance with the ISO Cleanliness Code, ISO 4406.There was also determined kinematic viscosity according to the standard EN ISO 3104+AC. FTIR analysis of the infrared spectrum was used to determine the degradation degree of the hydraulic fluid physical-chemical properties.

scholarly journals Ionic liquids – the path to the first industrial application

2021 ◽  
Author(s):  
Darko Lovrec
Keyword(s):  
Industrial Application ◽  
Hydraulic Fluid ◽  
Developmental Pathway ◽  
Base Oil ◽  
Industrial Environment ◽  
Development Path ◽  
Mineral Oils ◽  
Hydraulic Fluids ◽  
New Type ◽  
Approximate Composition

When using hydraulic fluids, users rarely ask themselves how the development of the hydraulic fluid they use in their hydraulic device has gone. Perhaps only curious users want to know the approximate composition of the newer, better hydraulic fluid, compared to the fluid of the previous generation. Rarely, however, do they know the developmental pathway of the new fluid. Even in the case of minor changes in the chemical composition of the fluid, e. g. a newer package of additives for mineral oils, or other base oil, requires lengthy fluid testing. First, in the manufacturer's laboratories, and then in the industrial environment. In the case of a completely new type of hydraulic fluid, the development path is much longer. The paper presents the behind-the-scenes development of a completely new type of hydraulic fluid - ionic liquid, from learning about the liquid itself all the way to industrial application.

scholarly journals Influence of differently viscous hydraulic fluid on the flow behaviour inside a hydraulic tank

2021 ◽  
Author(s):  
Ignacijo Biluš ◽  
Luka Lešnik ◽  
Luka Kevorkijan ◽  
Darko Lovrec
Keyword(s):  
Material Properties ◽  
Hydraulic System ◽  
Flow Behaviour ◽  
Hydraulic Fluid ◽  
Entire System ◽  
Flow Conditions ◽  
Lower Viscosity ◽  
Hydraulic Fluids ◽  
Detailed Simulation ◽  
The Impact

The viscosity of a hydraulic fluid is certainly one of the most important material properties of a fluid, as it affects a whole range of phenomena in the hydraulic system and the operation of the entire system. Among other things, it affects the efficiency of the hydraulic device directly. Thus, the development of hydraulic fluids goes in the direction of fluids with lower viscosity, which, in turn, results in different flow behaviour and processes inside the hydraulic tank. The paper presents the results of a study of the flow conditions in a small hydraulic tank for cases of different fluid viscosities. The results were obtained based on a detailed simulation of conditions inside the tank. Apart from the impact of the changed flow conditions, the lower viscosity of the liquid also influences the elimination of solid contaminants and air.

Bubble Elimination from Working Oil for Environmentally Friendly Hydraulic System Design

2012 ◽  
Vol 6 (4) ◽  
pp. 488-493 ◽  
Author(s):  
Yutaka Tanaka ◽  
◽  
Sayako Sakama ◽  
Ryushi Suzuki ◽  
Keyword(s):  
Cost Reduction ◽  
Hydraulic System ◽  
High Performance ◽  
Swirl Flow ◽  
Hydraulic Fluid ◽  
Air Bubbles ◽  
Hydraulic Systems ◽  
Hydraulic Fluids ◽  
Technical Issues ◽  
Hydraulic System Design

With a view to environmental compatibility, energy saving, cost reduction, and high performance and efficiency, one trend in hydraulic systems, particularly in mobile markets, is to design them to be more compact, require less hydraulic fluid in the reservoir, and use their working hydraulic fluid longer. Air bubbles entrained in working hydraulic fluids have greatly detrimental effects on the function and lifetime of hydraulic fluids, components, and systems. A bubble eliminator using a swirl flow that can eliminate air bubbles from working hydraulic fluid has been proposed and developed by our smart and clean hydraulic project. This paper focuses on technical issues related to air bubbles, the aging process of hydraulic oil, and a field test of the performance of the bubble eliminator.

Dynamic balance analysis of contamination control for hydraulic systems based on dynamic filtration ratio

2016 ◽  
Vol 68 (1) ◽  
pp. 45-51
Author(s):  
Guangying Ma ◽  
Shurong Ning ◽  
Yunlong Hu ◽  
jun Gao
Keyword(s):  
Hydraulic System ◽  
Dynamic Balance ◽  
Contamination Level ◽  
Hydraulic Systems ◽  
Level Control ◽  
Content Type ◽  
Contamination Control ◽  
Precise Control ◽  
Dynamic Filtration ◽  
The Relationship

Purpose – The aim of this study is to establish a dynamic model of the filtration ratio. For the problem that the measured value of the filtration ratio is far less than the theoretical value in the actual hydraulic filtering system, the paper aims to find the relationship between the filtration ratio and the parameters of the hydraulic systems, such as the contamination level and the dirt-holding quantity of the filter. Design/methodology/approach – The paper opted for the method of experimental analysis and simulation to determine the relationship between the filtration ratio and the parameters of the hydraulic system, and established a dynamic filtration ratio model. Findings – The paper provides a preliminary model of dynamic filtration ratio, and the model shows that the filtration ratio is exponentially related to the contamination level and the dirt-holding quantity. Different filters have different influence coefficients. The filtering capacity for a certain particle size and the contamination level control of the filter for different hydraulic systems can be judged according to the dynamic balance equation of hydraulic systems. Originality/value – The paper is useful in the selection of filters and in the precise control of the contamination level of the hydraulic system.

Tribological and electrical behavior of Cu-based composites with addition of Ti-doped NbSe2 nanoplatelets

2018 ◽  
Vol 70 (3) ◽  
pp. 560-567 ◽  
Author(s):  
Jian Feng Li ◽  
Qin Shi ◽  
HeJun Zhu ◽  
ChenYu Huang ◽  
Shuai Zhang ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Solid State ◽  
Friction Coefficient ◽  
Electrical Properties ◽  
Tribological Properties ◽  
Solid State Reaction ◽  
Electrical Contact ◽  
Solid State Reaction Method ◽  
Content Type ◽  
Reaction Method

Purpose This paper aims to clarify the size and morphology of transition metal dichalcogenides has an impact on lubrication performance of Cu-based composites. This study is intended to show that Cu-based electrical contact materials containing Nb0.91Ti0.09Se2 have better electrical and tribological properties than those containing NbSe2. The tribological properties of Cu-based with different Ti-dopped NbSe2 content were also discussed. Design/methodology/approach The NbSe2 and Nb0.91Ti0.09Se2 particles were fabricated by thermal solid state reaction method. The powder metallurgy technique was used to fabricate composites with varying Nb0.91Ti0.09Se2 mass fraction. The phase composition of Cu-based composites was identified by X-ray diffraction, and the morphology of NbSe2/Nb0.91Ti0.09Se2 and the worn surface of composites were characterized by scanning electron microscopy and transmission electron microscopy. In addition, the tribological properties of composites were appraised using a ball-on-disk multi-functional tribometer. The data of friction coefficient and resistivity were analyzed and the corresponding conclusion was drawn. Findings In comparison with the pure copper, Cu-based composites containing Nb0.91Ti0.09Se2/NbSe2 had a lower friction coefficient, illustrating the Nb0.91Ti0.09Se2 with nano-size particles prepared in this work is a perfect choice for the fabrication of excellent electrical contact composites. Compared to composites with NbSe2, composites containing Nb0.91Ti0.09Se2 have better tribological and electrical properties. Research limitations/implications Because of the use of thermal solid state reaction method, the size of NbSe2 and Nb0.91Ti0.09Se2 is relatively large. Therefore, the fabrication of finer particles of Nb0.91Ti0.09Se2 is encouraged. Originality/value In this paper, the authors discuss the tribological and electrical properties of Cu-based composites, and the value of optimum obtained as Nb0.91Ti0.09Se2 content is 15 Wt.%.

Rapid manufacturing of copper-graphene composites using a novel rapid tooling technique

2020 ◽  
Vol 26 (4) ◽  
pp. 765-776 ◽  
Author(s):  
Gurminder Singh ◽  
Pulak Mohan Pandey
Keyword(s):  
Electrical Conductivity ◽  
Electrical Properties ◽  
Wear Rate ◽  
Coefficient Of Friction ◽  
Rate Coefficient ◽  
Three Dimensional ◽  
Rapid Tooling ◽  
Content Type ◽  
Three Dimensional Printing ◽  
Dimensional Printing

Purpose The purpose of this study is to study the mechanical, tribological and electrical properties of the copper-graphene (Cu-Gn) composites fabricated by a novel rapid tooling technique consist of three-dimensional printing and ultrasonic-assisted pressureless sintering (UAPS). Design/methodology/approach Four different Cu-Gn compositions with 0.25, 0.5, 1 and 1.5 per cent of graphene were fabricated using an amalgamation of three-dimensional printing and UAPS. The polymer 3d printed parts were used to prepare mould cavity and later the UAPS process was used to sinter Cu-Gn powder to acquire free-form shape. The density, hardness, wear rate, coefficient of friction and electrical conductivity were evaluated for the different compositions of graphene and compared with the pure copper. Besides, the comparison was performed with the conventional method. Findings Cu-Gn composites revealed excellent wear properties due to higher hardness, and the lubrication provided by the graphene. The electrical conductivity of the fabricated Cu-Gn composites started increasing initially but decreased afterwards with increasing the content of graphene. The UAPS fabricated composites outperformed the conventional method manufactured samples with better properties such as density, hardness, wear rate, coefficient of friction and electrical conductivity due to homogeneous mixing of metal particles and graphene. Originality/value The fabrication of Cu-Gn composite freeform shapes was found to be difficult using conventional methods. The novel technique using a combination of polymer three-dimensional printing and UAPS as rapid tooling was introduced for the fabrication of freeform shapes of Cu-Gn composites and mechanical, tribological and electrical properties were studied. The method can be used to fabricate optimized complex Cu-Gn structures with improved wear and electrical applications.

Numerical and experimental studies on the thermal characteristics of the clutch hydraulic system with provision for oil flow

2019 ◽  
Vol 71 (6) ◽  
pp. 733-740 ◽  
Author(s):  
Biao Ma ◽  
Liang Yu ◽  
Man Chen ◽  
He Yan Li ◽  
Liang Jie Zheng
Keyword(s):  
Thermal Resistance ◽  
Network Model ◽  
Hydraulic System ◽  
Experimental Studies ◽  
Thermal Characteristics ◽  
Parameter Method ◽  
Content Type ◽  
Resistance Network ◽  
Oil Flow ◽  
Resistance Network Model

PurposeThis paper aims to investigate the thermal characteristics of the clutch hydraulic system under various oil flow conditions. Increasing the oil flow is one of the most important approaches to reduce the clutch temperature. However, the effect of the oil flow on the clutch temperature remains to be explored.Design/methodology/approachThe thermal resistance network model and the lumped parameter method are used to study the thermal characteristics of the clutch hydraulic system. The predicted temperature variations of the clutch and the oil are compared with experimental data.FindingsResults demonstrate that the larger the friction power is, the higher the temperatures of the clutch and the oil are. However, the temperature growth rates of the clutch and oil present different trends: the former decreases gradually and the latter increases constantly. Additionally, increasing the oil flow within a certain range gives rise to the decrease of clutch temperature and the increase of oil temperature; nevertheless, their variation trends are gradually weakening. When the oil flow is large enough, it brings a slight effect on the clutch temperature rise.Originality/valueThis paper extends the knowledge into the oil flow supply of the clutch hydraulic system. The conclusions can provide a theoretical guidance for the oil management of the transmission system. Additionally, the thermal resistance network model is also effective and efficient for other hydraulic equipment to predict the temperature variation.

Development of food products with addition of rapeseed presscake fermented by Rhizopus

2019 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Friedrich-Karl Lücke ◽  
Kathrin Tannhäuser ◽  
Amrita Sharma ◽  
Viktoria Fritz
Keyword(s):  
General Population ◽  
Design Methodology ◽  
Bitter Taste ◽  
Food Products ◽  
Consumer Acceptance ◽  
Plant Proteins ◽  
Content Type ◽  
Rapeseed Proteins ◽  
Practical Implications ◽  
Degree Of Degradation

Purpose The purpose of this paper is to explore the prospects and limitations of consumer acceptance towards food products that have been enriched with rapeseed protein in the form of fermented rapeseed presscake. Design/methodology/approach In total, 16 different food products with up to 18 per cent fermented rapeseed presscake were developed. Three types of vegetarian spreads and one type of bread were formulated, and consumer acceptance was assessed by sensory evaluation, questionnaires and in a focus group. Findings The fermentation of the rapeseed presscake by using the tempeh mould, Rhizopus oligosporus, had little if any effect on the bitterness of the presscake, and the bitter taste and aftertaste of the fermented presscake limited its use in food products. However, promising results were obtained when the breads and vegetarian spreads that were prepared with 5–6 per cent dried fermented rapeseed presscake were presented to sensory panels and to consumers, provided that the bitterness was masked, to some degree, by appropriate formulations and processes. Research limitations/implications Responders consisted mainly of younger people open to sustainable, plant-based nutrition, and may not represent the general population. Nevertheless, the results have implications for further research on utilization of rapeseed proteins. Practical implications It is possible to use the fermented rapeseed presscake to enrich various foods with protein or to replace other proteins, e.g. from animals or soybeans, provided that the degree of degradation of undesired compounds can be better standardized. Originality/value This study provides useful information for how to increase the use of underutilized plant proteins for human nutrition.

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