scholarly journals CALCULATION OF A SONOCAPILLARY EFFECT DEPENDENCE ON AN ULTRASONIC FREQUENCY BASED ON A THRESHOLD CAVITATION CRITERION

2020 ◽  
Vol 82 (1) ◽  
pp. 64-74
Author(s):  
N.V. Mikhailova ◽  
I.V. Smirnov ◽  
A. Sharipova ◽  
V. Slesarenko
Keyword(s):  
Experimental Data ◽  
Capillary Pressure ◽  
Process Zone ◽  
Ultrasonic Frequency ◽  
Threshold Pressure ◽  
Acoustic Vibrations ◽  
Capillary Effect ◽  
Frequency Range ◽  
Ultrasound Frequency ◽  
Cavitation Bubbles

The possibility of calculating parameters of the ultrasonic capillary effect depending on frequency of acoustic vibrations in liquid is considered. According to known experimental data, the intensification of fluid motion in the capillary is mainly associated with the formation and collapse of cavitation bubbles at the capillary end. Therefore, it is assumed that the ultrasonic capillary effect occurs as a result of cavitation processes at the entrance to the capillary channel, while cavitation processes depend on the frequency of ultrasonic vibrations. The threshold pressure at cavitation, leading to the rise of fluid, for a given ultrasound frequency is determined by the criterion of incubation time of cavitation. The size and number of cavitation bubbles at the considered threshold pressure depend on ultrasound frequency. The number of bubbles in the cavitation area is determined by solving the problem of packing equal circles in a larger circle, taking into account the distance the influence of the bubbles on each other. The height of the liquid rise is calculated based on the assumption that during one cycle of oscillation of the cavitation region, the sound capillary pressure performs the work on lifting the liquid column to a certain height due to the energy of collapsed bubbles. This approach makes it possible to determine the threshold amplitude of acoustic vibrations and evaluate the corresponding behaviour of sound-capillary pressure in the frequency range of 7-62 kHz. The specified range is determined by the frequency requirements for the ratio of the size of the cavitation process zone and the capillary diameter. Thus, the obtained model of the ultrasonic capillary effect takes into account the diameter of the capillary and allows to determine the frequency range over which this effect can be realized. The calculation results show good agreement with the known experimental data in water. The results of calculations using the model showed that the highest sound capillary pressure is reached in the range of 10-20 kHz.

scholarly journals High Frequency Magnetoimpedance of FeNi/Cu/FeNi Sensitive Elements with Different Geometries

2009 ◽  
Vol 152-153 ◽  
pp. 373-376 ◽  
Author(s):  
Stanislav O. Volchkov ◽  
Andrey V. Svalov ◽  
G.V. Kurlyandskaya
Keyword(s):  
Magnetic Field ◽  
Experimental Data ◽  
External Magnetic Field ◽  
Finite Elements ◽  
Magnetic Anisotropy ◽  
Constant Magnetic Field ◽  
High Frequency ◽  
Complex Impedance ◽  
Rf Sputtering ◽  
Frequency Range

In this work magnetoimpedance (MI) behaviour was studied experimentally for Fe19Ni81(175 nm)/Cu(350 nm)/Fe19Ni81(175 nm) sensitive elements deposited by rf-sputtering. A constant magnetic field was applied in plane of the sandwiches during deposition perpendicular to the Cu-lead in order to induce a magnetic anisotropy. Sandwiches with different width (w) of FeNi parts were obtained. The complex impedance was measured as a function of the external magnetic field for a frequency range of 1 MHz to 700 MHz for MI elements with different geometries. Some of MI experimental data are comparatively analysed with finite elements numerical calculations data. The obtained results can be useful for optimization of the design of miniaturized MI detectors.

Oscillations and Long-Lasting Correlations in a Model of the Lateral Geniculate Nucleus and Visual Cortex

2000 ◽  
Vol 84 (4) ◽  
pp. 1863-1868 ◽  
Author(s):  
Kyle L. Kirkland ◽  
Adam M. Sillito ◽  
Helen E. Jones ◽  
David C. West ◽  
George L. Gerstein
Keyword(s):  
Experimental Data ◽  
Visual Cortex ◽  
Cell Membrane ◽  
Lateral Geniculate Nucleus ◽  
Feedback Inhibition ◽  
Frequency Range ◽  
Lateral Geniculate ◽  
Low Threshold ◽  
Thalamocortical System

We have previously developed a model of the corticogeniculate system to explore cortically induced synchronization of lateral geniculate nucleus (LGN) neurons. Our model was based on the experiments of Sillito et al. Recently Brody discovered that the LGN events found by Sillito et al. correlate over a much longer period of time than expected from the stimulus-driven responses and proposed a cortically induced slow covariation in LGN cell membrane potentials to account for this phenomenon. We have examined the data from our model, and we found, to our surprise, that the model shows the same long-term correlation. The model's behavior was the result of a previously unsuspected oscillatory effect, not a slow covariation. The oscillations were in the same frequency range as the well-known spindle oscillations of the thalamocortical system. In the model, the strength of feedback inhibition from the cortex and the presence of low-threshold calcium channels in LGN cells were important. We also found that by making the oscillations more pronounced, we could get a better fit to the experimental data.

scholarly journals STUDY OF PROCESSES OF PRESSURE AND IMPULSE FREQUENCY INFLUENCE ON PENETRATION OF LIQUIDS IN THE SAND SAMPLES

2016 ◽  
pp. 120-125
Author(s):  
M. Ya. Habibullin ◽  
R. R. Shangareyev
Keyword(s):  
Experimental Data ◽  
Oil Recovery ◽  
Pressure Fluctuations ◽  
Experimental Studies ◽  
Regression Equations ◽  
Linear Variation ◽  
Frequency Range ◽  
Impulse Frequency ◽  
Overburden Pressure

The article deals with the issues related to the hydrocarbon reservoirs oil recovery enhancement. It describes the bench laboratory experimental studies. The results obtained during determination of fluid leakage through the rock samples and the amount of absorption of pressure fluctuations at various regime parameters are presented. Using the experimental data the regression analysis was performed on the basis of which the qualitative correlations between factorial and resultant features were identified. Using the regression equations the graphic relations were constructed. It was found that with increasing the oscillation frequency of the fluid the amount of fluid passing through the sample of porous medium increased, with the highest value of q reached at the frequency range of 600 ... 1000 Hz. With increase in the oscillations penetration depth the absorption of the amplitude of the pressure fluctuations corresponds to the linear decrease, and with the overburden pressure increase the linear variation of absorption is distorted.

scholarly journals MOLECULAR MECHANISM OF RELAXATION ABSORPTION OF ULTRASONIC WAVES IN AN AQUEOUS SOLUTION OF CALCIUM ACETATE

InterConf ◽  
2021 ◽  
pp. 970-978
Author(s):  
Z. Nizomov ◽  
M. Asozoda ◽  
A. Olimi ◽  
A. Karimzoda
Keyword(s):  
Experimental Data ◽  
Aqueous Solution ◽  
Sodium Chloride ◽  
Sodium Acetate ◽  
Ultrasonic Waves ◽  
Calcium Acetate ◽  
Acetate Anion ◽  
Frequency Range ◽  
Calcium Cations ◽  
Calcium Cation

The absorption of ultrasonic waves in the frequency range from 6 to 146 MHz in aqueous solutions of sodium acetate, sodium chloride and calcium has been studied. It was found that only in solutions of calcium cations and acetate anion present simultaneously, relaxation absorption of ultrasonic waves is observed. The experimental data obtained indicate that the observed relaxation absorption of ultrasound in the studied frequency range by an aqueous solution of calcium acetate is associated with the interaction of the acetate anion with the calcium cation in the solution.

Performance Improvement of RF Inductors Using LTCC Technology

2011 ◽  
Vol 2011 (CICMT) ◽  
pp. 000054-000058 ◽  
Author(s):  
Goran Radosavljević ◽  
Andrea Marić ◽  
Walter Smetana ◽  
Ljiljana Živanov
Keyword(s):  
Experimental Data ◽  
Low Temperature ◽  
Design Optimization ◽  
Quality Factor ◽  
Performance Improvement ◽  
Air Gap ◽  
Frequency Range ◽  
Operating Frequency Range ◽  
Rf Inductors ◽  
First Time

This paper presents for the first time a parallel comparison of the performance of RF inductors realized on different substrate configurations. Presented inductors are meander type structures fabricated in Low Temperature Co-fired Ceramic (LTCC) technology. Also, chosen material is never before implemented for inductor fabrication. The performance improvement is achieved by design optimization of different substrate configurations that incorporate placement of an air-gap beneath the inductor and/or introduction of an additional shielding layer on the top. Designed structures are characterized on the basis of simulation and experimental data, achieving good correlation between obtained results. Presented results show over 30 % increase in quality factor and widening of the operating frequency range by over 55 %.

Finite Element Analysis of SiCp/Al Model of Unit Cell during Ultrasonic Vibration Scratching

2016 ◽  
Vol 693 ◽  
pp. 1022-1029
Author(s):  
G.Q. Liang ◽  
Ping Fa Feng ◽  
Jian Fu Zhang
Keyword(s):  
Finite Element ◽  
Maximum Amplitude ◽  
Element Model ◽  
Ultrasonic Frequency ◽  
Frequency Range ◽  
Element Analysis ◽  
Scale Modeling ◽  
Sic Particles ◽  
Significant Damage ◽  
Extent Of Damage

In this paper, finite element model of SiCp /Al single cell body and single diamond particles were established by cross-scale modeling method. The results shows that the extent of damage of SiC particles increased with the increase of amplitude and frequency; The integrity of SiC particles are still better under the ultrasonic frequency 20000 Hz and the maximum amplitude 5um,so the optimal frequency range of ultrasonic scratch is (20000-30000)Hz. As for 22000 Hz, the integrity of SiC particles was better under the amplitude 4um,while the SiC particles have a significant damage in the border area under the amplitude 5um,so the best frequency and amplitude for ultrasonic scratches are: 22000 Hz and 4 um.

Mathematical Modeling of Capillary Pumping Within Micron Sized Channels

2013 ◽  
Author(s):  
Yuelei Yang ◽  
Dan Zhang
Keyword(s):  
Mathematical Modeling ◽  
Experimental Data ◽  
Mathematical Model ◽  
Capillary Pressure ◽  
Heat Engine ◽  
Velocity Profiles ◽  
Vof Method ◽  
Numerical Results ◽  
Micro Heat Engine ◽  
Volume Of Fluids

This paper introduces a mathematical model which can be used to simulate the capillary pumping process of a micro heat engine. The micro heat engine has micron sized channels where the capillary pumping occurs. The classic Volume of Fluids (VOF) method is applied to obtain the velocity profiles of the fluids and to track the motions of the liquid-gas interfaces. The numerical results based this model have been compared with the experimental data and the initial retard of the pumping has been found and this phenomenon can be explained by the initial capillary pressure build-ups across the liquid-gas interfaces.

A New Unsteady-State Model for Calculating Oil-Water Relative Permeability of Low-Permeability/Ultra-Low Permeability Reservoirs

2012 ◽  
Vol 616-618 ◽  
pp. 964-969 ◽  
Author(s):  
Yue Yang ◽  
Xiang Fang Li ◽  
Ke Liu Wu ◽  
Meng Lu Lin ◽  
Jun Tai Shi
Keyword(s):  
Porous Media ◽  
Pressure Gradient ◽  
Capillary Pressure ◽  
Relative Permeability ◽  
Oil Reservoirs ◽  
Flow In Porous Media ◽  
Low Permeability ◽  
Threshold Pressure ◽  
Flow Process ◽  
Threshold Pressure Gradient

Oil and water relative permeabilities are main coefficients in describing the fluid flow in porous media; however, oil and water relative permeability for low - ultra low perm oil reservoir can not be obtained from present correlations. Based on the characteristics of oil and water flow in porous media, the model for calculating the oil and water relative permeability of low and ultra-low perm oil reservoirs, which considering effects of threshold pressure gradient and capillary pressure, has been established. Through conducting the non-steady oil and water relative permeability experiments, oil and water relative permeability curves influenced by different factors have been calculated. Results show that: the threshold pressure gradient more prominently affects the oil and water relative permeability; capillary pressure cannot influence the water relative permeability but only the oil relative permeability. Considering effects of threshold pressure gradient and capillary pressure yields the best development result, and more accordant with the flow process of oil and water in low – ultra low perm oil reservoirs.

A Study of Gravity Counterflow Segregation

1962 ◽  
Vol 2 (02) ◽  
pp. 185-193 ◽  
Author(s):  
E.E. Templeton ◽  
R.F. Nielsen ◽  
C.D. Stahl
Keyword(s):  
Experimental Data ◽  
Pressure Gradient ◽  
Capillary Pressure ◽  
Closed System ◽  
Fractional Flow ◽  
Flow Rates ◽  
Flow Equations ◽  
Actual Flow ◽  
Capillary Pressures ◽  
Darcy Equations

Abstract It has been customary, in predicting saturation changes, to use the Leverett "fractional flow formula", obtained by eliminating the unknown pressure gradient from the generalized Darcy equations for the separate phases. The formula presents difficulties in the case of counterflow, since the "fractional" flow may be negative, greater than unity, or, in the case of a closed system, infinite. Recently, it has been shown by several authors that the corresponding equations (with capillary pressure and gravity terms) for actual flow of the phase may be used just as well. These equations are in agreement with Pirson's statement that, if the two mobilities differ considerably from each other in a closed system, the flow is largely governed by the lower value. The present study was undertaken because of an apparent lack of experimental data on gravity counterflow with which to test the theory. A 4-ft sandpacked tube in a vertical position was employed. Electrodes for determining saturations by resistivity were spaced along the tube, one phase being always an aqueous salt solution. Air, heptane, naphtha, or Bradford crude oil was used for the other phase. A reasonably uniform initial saturation was set up by pumping the phases through the system, after which the tube was shut in and saturation profiles obtained at definite intervals. Cumulative flows over certain horizontal levels were obtained by integration of the distributions; hence, differentiation of the cumulative flows with respect to time gave instantaneous flow rates. To compare experimental and theoretical flow values, capillary pressures were assumed given by the final saturation-distribution curve. The upper part corresponds to the "drainage" region and the lower part to the "imbibition" region, where trapping of the nonwetting phase occurred. While calculations indicated that the capillary pressure saturation function and, probably, the relative permeability saturation functions changed during the segregation, the relation of the measured rates to saturation distributions are in general accord with the frontal-advance equation. It appears that the Darcy equations, as modified for the separate phases, are generally valid for counterflow due to density differences. The usual method of predicting saturation changes, which involves a continuity equation and the elimination of the unknown pressure gradient from the flow equations, should therefore be applicable. However, the need for advance knowledge of drainage and imbibition "capillary pressures" and relative permeabilities during various stages presents difficulties. Introduction The present study was undertaken because of a seeming lack of experimental data relating to vertical counterflow of fluids of different densities in porous media. In particular, it was desired to determine whether data obtained from these laboratory tests were in accordance with certain mathematical treatments of counterflow which have been proposed. The gravity "correction" has been incorporated into the flow equations (and, hence, into displacement theory) nearly as long as both have been used. Field and laboratory data have generally borne out the validity of the theory as applied, for instance, to downward displacement by gas, with all fluids moving downward. However, the modifications for counterflow have only recently been pointed out. It has been customary to use fractional flow rates instead of actual flow rates in displacement calculations. In the case of counterflow, this results in negative values, values greater than unity and, when rates are equal and opposite, in infinite values. As pointed out by Sheldon, et al, and by Fayers and Sheldon, actual flow rates may be used just as well. The fact that these may be of opposite signs for the two fluids does not present any difficulty. SPEJ P. 185^

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