Developed Measuring Methods for Hydraulic Fluid Dynamics and Viscosity at Extreme Pressures and Temperatures

2014 ◽  
Author(s):  
J.-P. Karjalainen ◽  
R. Karjalainen ◽  
K. Huhtala
Keyword(s):  
Power Transmission ◽  
Measuring System ◽  
Hydraulic Fluid ◽  
User Friendliness ◽  
Fluid Properties ◽  
Transmission Fluid ◽  
Viscosity Grade ◽  
And Control ◽  
Fluid Parameters ◽  
Fluid Characteristics

Hydraulic fluid is one of the most important components in every fluid power system. Therefore, fluid properties have to be known with a good accuracy in an increasing number of applications, for example in system’s design, modelling and control. The fluid of interest may be a power transmission fluid as well as a fuel. In defining the needed fluid characteristics, the large variety of different fluid types sets many demands for a single measuring system. Moreover, known fluid properties, of fuels in particular, are needed at constantly higher pressures and temperatures, raising the bar for practical measuring concepts — user-friendliness, safety and equipment cost are also essential criteria. In this paper, two accurate, but rather simple and affordable measuring concepts are presented. The speed of sound in a fluid, hydraulic fluid density and adiabatic tangent fluid bulk modulus are all defined with a direct measurement of the pressure wave propagation. The dynamic and kinematic fluid viscosities are defined with a remotely operated, modified falling ball viscometer. Both the presented methods have been developed further from the previously published concepts of the same authors. With these improved systems, all the mentioned fluid parameters can reliably be measured at up to at least 2,500 bar and at up to at least +150°C. Moreover, the same equipment can be applied to any type of hydraulic fluid, a fuel or a power transmission fluid, regardless of the base fluid, additives or viscosity grade. In addition to presenting the measuring concepts and the equipment used in detail, a selected sample of experimental results will also be presented to demonstrate the performance characteristics of the methods.

An Extended Second Order Polynomial Model for Hydraulic Fluid Density

2013 ◽  
Author(s):  
J.-P. Karjalainen ◽  
R. Karjalainen ◽  
K. Huhtala
Keyword(s):  
Power Transmission ◽  
Second Order ◽  
Polynomial Model ◽  
Hydraulic Fluid ◽  
Wide Range ◽  
Fuel Oils ◽  
Hydraulic Fluids ◽  
Order Polynomial ◽  
Temperature Ranges ◽  
Fluid Characteristics

In this paper, a second order polynomial model for predicting the pressure-temperature behaviour of the density of any hydraulic fluid is presented. The model is an extension of the previously published model by the same authors for more moderate operating temperatures. Nevertheless, for a user the extension will not add any more complexity to the model. Even at a wider operating range, the density model can still always be parameterized without any unknown variables, once the standard fluid characteristics are available. It is shown that compared to the measured values the maximum modelling error is well within 1% at the studied pressure range of up to 1500 bar, and at the studied temperature ranges overall covering from +20 to +130°C, with all the studied fluids. This study includes 10 highly different hydraulic fluids used in various fluid power applications as power transmission fluids or fuel oils. The studied fluids have a density range from 827 to 997.2 kg/m3, and an ISO VG range from 2.6 to 1187. Also the studied base fluids cover a wide range. Moreover, the studied fluids contain different additives or not even additives at all (crude oils). Neither the base fluid nor the additives will be discovered to affect the received modelling accuracy.

scholarly journals ON THE MANAGEMENT OF URBAN ELECTRIC NETWORKS IN THE CONDITIONS OF THE SMART GRID

2018 ◽  
Vol 61 (1) ◽  
pp. 15-27 ◽  
Author(s):  
M. А. Fursanov ◽  
A. A. Zalotoy
Keyword(s):  
Smart Grid ◽  
Electric Power ◽  
Power Transmission ◽  
Electrical Networks ◽  
Electric Networks ◽  
Urban Networks ◽  
Theoretical Criterion ◽  
Active Power Losses ◽  
And Control ◽  
The City

The issues of prospective operation of the city electric networks in the conditions of the MART GRID, which will be quite different as compared to the traditional understanding and approaches, are under consideration. This requires the selection and application of appropriate analytical criteria and approaches to assessment, analysis and control of the networks. With this regard the following criteria are recommended: in a particular case – the optimal (minimal) technological electric power consumption (losses), while in general – economically reasonable (minimal) cost value of electric power transmission. It should be also borne in mind that contemporary urban networks are actively saturated with distributed sources of small generation that have radically changed the structure of electrical networks; therefore, account for such sources is an absolutely necessary objective of management regimes of urban electric networks, both traditional and in associated with the SMART GRID. A case of the analysis and control of urban electric 10 kV networks with distributed small sources of generation has been developed and presented according to the theoretical criterion of minimum relative active power losses in the circuit as a control case. The conducted research makes it possible to determine the magnitude of the tolerance network mode from the point of the theoretical minimum. 

Thermal Analysis of a DC Motor Cooling System Availing an Engine Test Stand of Electrical Race Car

2015 ◽  
Vol 809-810 ◽  
pp. 1145-1150 ◽  
Author(s):  
Maja Baier ◽  
Mateusz Dziewior ◽  
Jakub Franiasz ◽  
Michal Zuk
Keyword(s):  
Thermal Analysis ◽  
Cooling System ◽  
Dc Motor ◽  
Test Stand ◽  
Measuring System ◽  
Engine Test ◽  
Modular Construction ◽  
Race Car ◽  
Motor Cooling ◽  
And Control

Thermal analysis of a DC motor cooling system and description of measurement system applied to an engine test stand are the main topics of the paper. The motor that is being tested comes from the electric vehicle of Silesian Greenpower project whose aim is to design and build energy efficient bolids in order to participate in international races in Great Britain. During the designing process of the car, minimizing energy losses and maximizing powertrain efficiency are the main aspects taken into consideration. One of the crucial issues to accomplish these goals is to maintain optimal performance of the motor by applying effective cooling. The engine test stand used in this research was designed especially for Silesian Greenpower vehicles. Thanks to its modular construction and versatility, it enables measuring many different parameters of the motor and powertrain. In this paper the thermal analysis is described as well as how the measuring system of the engine stand works. The thermal analysis described in the article occurred to be very helpful in improving the cooling system and motor performance in the same time. The advanced measuring and control system of the test stand enables conducting versatile analysis of the DC motor and the powertrain.

Possible Implementation of Ex-core Measurement in TEPLATOR Graphite Reflector

2021 ◽  
Author(s):  
Eva Vilimova ◽  
Tomas Peltan ◽  
Jana Jiricková
Keyword(s):  
Neutron Flux ◽  
District Heating ◽  
Flux Measurement ◽  
Heating System ◽  
Fast Response ◽  
Reactor Power ◽  
Measuring System ◽  
Monte Carlo Code ◽  
District Heating System ◽  
And Control

Abstract An ex-core neutron flux measurement is a crucial system for all common power reactors. It is necessary to monitor the neutron flux and control the chain reaction, therefore the ex-core neutron flux measurement is one of the main safety and control systems. The main advantage of this arrangement of detectors is a fast response to neutron flux change, which determines the reactor power change. Regarding to the new reactor concepts, it is important to deal with improved detection systems suitable for these reactors. Many of the modern reactor concepts are based on a graphite moderator or reflector, which is also the case of the TEPLATOR. The TEPLATOR is a solution of a district heating system based on heavy water as a moderator and graphite as a reflector. The TEPLATOR is designed to use irradiated fuel from the commercial PWR or BWR reactors, which has low to intermediate burnup. This article is focused on the verification of the possible use of the special neutron measuring system placed in the graphite reflector. The Monte Carlo code Serpent was used for the calculations performed in this article.

scholarly journals Treatment Success and User-Friendliness of An Electric Toothbrush App: A Pilot Study

2020 ◽  
Vol 8 (3) ◽  
pp. 97
Author(s):  
Viviane Humm ◽  
Daniel Wiedemeier ◽  
Thomas Attin ◽  
Patrick Schmidlin ◽  
Stefanie Gartenmann
Keyword(s):  
Pilot Study ◽  
Treatment Success ◽  
Test Group ◽  
Plaque Index ◽  
Control Group ◽  
Controlled Clinical Trial ◽  
User Friendliness ◽  
Short Period ◽  
Electric Toothbrush ◽  
And Control

Electronic and mobile health (eHealth/mHealth) are rapidly growing areas in medicine and digital technologies are gaining importance. In dentistry, digitalization is also an emerging topic, whereby more and more applications are being offered. As an example, using real-time feedback, digital application software (an app) was designed to help users brush their teeth more accurately. However, there is no data on the effectiveness and haptic of such apps. Therefore, a single-blinded, randomized controlled clinical trial was designed: twenty volunteers received an electric toothbrush with an associated app to assess whether the app-assisted toothbrushing is better than without. After a short period of familiarization with the electric toothbrush, plaque index (O‘Leary et al. 1972) was recorded and subjects were assigned to the test (with app; n = 10) or the control group (no app; n = 10). At the end of the 2-week pilot study period, plaque was again assessed and participants in the test group completed a questionnaire about the app’s user-friendliness. Statistical analysis revealed no significant differences between the test and control groups. The plaque index improved on average by 8.5% points in the test and 4.7% points in the control group. Fifty percent of the test group participants were of the opinion that they had achieved better cleaning results and would recommend the app to others, although the app contributed only marginally to increased plaque removal. However, such apps may nevertheless be helpful as motivational tools, especially when tracking and monitoring cleaning data. Therefore, more development and research on this topic is indicated.

Modeling, Model Reduction, and Control of a Hands-Free Two-Wheeled Self-Balancing Scooter

2020 ◽  
pp. 185-202
Author(s):  
Qiong Li ◽  
Wangling Yu ◽  
H. Henry Zhang
Keyword(s):  
Model Reduction ◽  
Large Scale ◽  
Power Transmission ◽  
System Response ◽  
Real Time Control ◽  
Time Control ◽  
Iteration Period ◽  
Synergistic Approach ◽  
Model Reduction Technique ◽  
And Control

Designing a two-wheeled self-balancing scooter involves in the synergistic approach of multidisciplinary engineering fields with mutual relationships of power transmission, mass transmission, and information transmission. The scooter consists of several subsystems and forms a large-scale system. The mathematical models are in the complex algebraic and differential equations in the form of high dimension. The complexity of its controller renders difficulties in its realization due to the limit of iteration period of real time control. Routh model reduction technique is employed to convert the original high-dimensional mathematical model into a simplified lower dimensional form. The modeling is derived using a unified variational method for both mechanical and electrical subsystems of the scooter, and for the electronic components equivalent circuit method is adopted. Simulations of the system response are based on the reduced model and its control design. A prototype is developed and realized with Matlab-Labview simulation and control environment.

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