Second Order Polynomial Model for Fluid Dynamics in High Pressure

2009 ◽  
Author(s):  
Juho-Pekka Karjalainen ◽  
Reijo Karjalainen ◽  
Kalevi Huhtala ◽  
Matti Vilenius
Keyword(s):  
Dynamic Properties ◽  
Fluid Model ◽  
Fluid Dynamic ◽  
Measuring Method ◽  
Second Order ◽  
Model Parameters ◽  
Hydraulic Fluid ◽  
Measurement Results ◽  
Order Polynomial ◽  
Fluid Characteristics

This paper suggests second order polynomials for modeling hydraulic fluid dynamic properties — tangent bulk modulus, density and speed of sound in fluid. Model parameters can be calculated from ISO fluid characteristics data available for every commercial hydraulic fluid. The accuracy of the models is verified with measurements at pressures up to 1500 bar. The measurement results as well as the measuring method are also introduced. Although the models are quite simple, correlation with the measurement results is excellent.

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.

Uncertainty of the Diffusion Measurements on Scaffolds for Cell Growth

2011 ◽  
Vol 312-315 ◽  
pp. 770-775 ◽  
Author(s):  
Guido Sassi ◽  
Marco Bernocco ◽  
Mariapaola Sassi
Keyword(s):  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Solid Particles ◽  
Liquid Volume ◽  
Model Parameters ◽  
Diffusivity Measurement ◽  
Fitting Procedures ◽  
Definition Of

The regenerative medicine uses gel and porous solid matrices as scaffolds for the growth of the stem cells in 3D structures. The structural and fluid dynamic properties of the matrices have been recognized to highly affect the behaviour and functions of the cells. The procedures of production and the clinical use of the matrices need a reliable and reproducible characterization of their properties, this means that the concepts of metrology must be applied to the measurement and definition of all the relevant properties. This paper deals with the calculation of uncertainty for diffusivity measurement in solids and the role of uncertainty in designing the measurement. Diffusion of a solute in spherical solid particles dispersed in a limited liquid volume where considered as measurement method for a Ca-alginate polymer. The model sensitivity to the concentration measurements, the model parameters and the fitting procedures have been discussed.

scholarly journals Modeling of German Low Voltage Cables with Ground Return Path

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1265 ◽  
Author(s):  
Johanna Geis-Schroer ◽  
Sebastian Hubschneider ◽  
Lukas Held ◽  
Frederik Gielnik ◽  
Michael Armbruster ◽  
...  
Keyword(s):  
Low Voltage ◽  
Measurement Data ◽  
Analytical Calculation ◽  
Laboratory Measurement ◽  
Model Parameters ◽  
Calculation Methods ◽  
Modeling Approach ◽  
Measurement Results ◽  
Simulation Results ◽  
Return Path

In this contribution, measurement data of phase, neutral, and ground currents from real low voltage (LV) feeders in Germany is presented and analyzed. The data obtained is used to review and evaluate common modeling approaches for LV systems. An alternative modeling approach for detailed cable and ground modeling, which allows for the consideration of typical German LV earthing conditions and asymmetrical cable design, is proposed. Further, analytical calculation methods for model parameters are described and compared to laboratory measurement results of real LV cables. The models are then evaluated in terms of parameter sensitivity and parameter relevance, focusing on the influence of conventionally performed simplifications, such as neglecting house junction cables, shunt admittances, or temperature dependencies. By comparing measurement data from a real LV feeder to simulation results, the proposed modeling approach is validated.

scholarly journals A second-order multi-fluid model for evaporating sprays

2005 ◽  
Vol 39 (5) ◽  
pp. 931-963 ◽  
Author(s):  
Guillaume Dufour ◽  
Philippe Villedieu
Keyword(s):  
Fluid Model ◽  
Second Order

Investigation of Fluid Dynamic Properties of Liquid Field’s Metal

2013 ◽  
Author(s):  
Adam Lipchitz ◽  
Theophile Imbert ◽  
Glenn D. Harvel
Keyword(s):  
Numerical Modeling ◽  
Liquid Metal ◽  
Linear Dependence ◽  
Dynamic Properties ◽  
Fluid Dynamic ◽  
Weight Percent ◽  
Rotational Viscometer ◽  
Liquid States ◽  
Increasing Temperature ◽  
Solid And Liquid States

The density and viscosity Field’s metal is measured in this work and compared to traditional liquid metal coolants such as sodium and lead-bismuth eutectic. Field’s metal is a eutectic of the ternary In-Bi-Sn system. The alloy is by weight percent is 51% indium, 32.5% bismuth and 16.5% tin and possesses a melting temperature of 333 K. This work experimentally measures the density and viscosity of Field’s metal for numerical modeling and thermal hydraulic applications. The density of Field’s metal is measured using a pycnometer. The density is determined for both its solid and liquid states. In its liquid state Field’s metal is found to have a linear dependence with respect to increasing temperature. The viscosity of Field’s metal is measured using a rotational viscometer. The viscosity is measured is to be 27 mPa-s at 353 K, however further investigation is required to determine a trend at higher temperatures.

Identification of ’Effective’ Linear Joints Using Coupling and Joint Identification Techniques

1998 ◽  
Vol 120 (2) ◽  
pp. 331-338 ◽  
Author(s):  
Y. Ren ◽  
C. F. Beards
Keyword(s):  
Dynamic Properties ◽  
Real Life ◽  
Model Parameters ◽  
Coupling Technique ◽  
Alternative Approach ◽  
Identification Technique ◽  
Joint Identification ◽  
Stiff Joint ◽  
Almost All ◽  
Identification Techniques

Almost all real-life structures are assembled from components connected by various types of joints. Unlike many other parts, the dynamic properties of a joint are difficult to model analytically. An alternative approach for establishing a theoretical model of a joint is to extract the model parameters from experimental data using joint identification techniques. The accuracy of the identification is significantly affected by the properties of the joints themselves. If a joint is stiff, its properties are often difficult to identify accurately. This is because the responses at both ends of the joint are linearly-dependent. To make things worse, the existence of a stiff joint can also affect the accuracy of identification of other effective joints (the term “effective joints” in this paper refers to those joints which otherwise can be identified accurately). This problem is tackled by coupling these stiff joints using a generalized coupling technique, and then the properties of the remaining joints are identified using a joint identification technique. The accuracy of the joint identification can usually be improved by using this approach. Both numerically simulated and experimental results are presented.

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