Response of a spinning liquid column to axial excitation

Basic Statements of Research and Magnetic Field of Axial Excitation Inductor GeneratorIn this work the main features of axial excitation inductor generators are described. Mathematical simulation of a magnetic field is realized by using the finite element method. The objective of this work is to elucidate how single elements shape, geometric dimensions and magnetic saturation of magnetic system affect the main characteristics of the field (magnetic induction, magnetic flux linkage). The main directions of a magnetic system optimization are specified.

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VIBRATION CONTROL OF SLENDER STRUCTURES WITH OPTIMIZED LIQUID COLUMN VIBRATION ABSORBERS

10.26678/abcm.cobem2019.cob2019-0470 ◽

2019 ◽

Author(s):

Jéssica Carolina Barbosa Vieira ◽

Thiago da Silva ◽

Carlos Alberto Bavastri

Keyword(s):

Vibration Control ◽

Liquid Column ◽

Vibration Absorbers ◽

Slender Structures

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Non-stationary process characteristics of the gas outflow into a liquid

Multiphase Systems ◽

10.21662/mfs2019.2.012 ◽

2019 ◽

Vol 14 (2) ◽

pp. 82-88

Author(s):

M.V. Alekseev ◽

I.S. Vozhakov ◽

S.I. Lezhnin

Keyword(s):

Numerical Simulation ◽

Liquid Column ◽

Gas Content ◽

Liquid Lead ◽

Gas Flows ◽

Asymptotic Model ◽

Process Characteristics ◽

Significant Difference ◽

Order Of Magnitude ◽

Volume Method

A numerical simulation of the process of the outflow of gas under pressure into a closed container partially filled with liquid was carried out. For comparative theoretical analysis, an asymptotic model was used with assumptions about the adiabaticity of the gas outflow process and the ideality of the liquid during the oscillatory one-dimensional motion of the liquid column. In this case, the motion of the liquid column and the evolution of pressure in the gas are determined by the equation of dynamics and the balance of enthalpy. Numerical simulation was performed in the OpenFOAM package using the fluid volume method (VOF method) and the standard k-e turbulence model. The evolution of the fields of volumetric gas content, velocity, and pressure during the flow of gas from the high-pressure chamber into a closed channel filled with liquid in the presence of a ”gas blanket“ at the upper end of the channel is obtained. It was shown that the dynamics of pulsations in the gas cavity that occurs when the gas flows into the closed region substantially depends on the physical properties of the liquid in the volume, especially the density. Numerical modeling showed that the injection of gas into water occurs in the form of a jet outflow of gas, and for the outflow into liquid lead, a gas slug is formed at the bottom of the channel. Satisfactory agreement was obtained between the numerical calculation and the calculation according to the asymptotic model for pressure pulsations in a gas projectile in liquid lead. For water, the results of calculations using the asymptotic model give a significant difference from the results of numerical calculations. In all cases, the velocity of the medium obtained by numerical simulation and when using the asymptotic model differ by an order of magnitude or more.

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Detachment of a drop from an internal wall in a pulsed liquid-liquid column

Chemical Engineering Science ◽

10.1016/s0009-2509(99)00502-3 ◽

2000 ◽

Vol 55 (11) ◽

pp. 2073-2088 ◽

Cited By ~ 11

Author(s):

A Mate ◽

O Masbernat ◽

C Gourdon

Keyword(s):

Liquid Column ◽

Internal Wall

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Analytical Modeling of a Doubly Clamped Flexible Piezoelectric Energy Harvester with Axial Excitation and Its Experimental Characterization

Sensors ◽

10.3390/s21113861 ◽

2021 ◽

Vol 21 (11) ◽

pp. 3861

Author(s):

Jie Mei ◽

Qiong Fan ◽

Lijie Li ◽

Dingfang Chen ◽

Lin Xu ◽

...

Keyword(s):

Output Power ◽

Power Output ◽

Output Voltage ◽

Energy Harvester ◽

Load Resistance ◽

Engineering Practice ◽

Maximum Output ◽

Widespread Application ◽

Piezoelectric Energy ◽

Axial Excitation

With the rapid development of wearable electronics, novel power solutions are required to adapt to flexible surfaces for widespread applications, thus flexible energy harvesters have been extensively studied for their flexibility and stretchability. However, poor power output and insufficient sensitivity to environmental changes limit its widespread application in engineering practice. A doubly clamped flexible piezoelectric energy harvester (FPEH) with axial excitation is therefore proposed for higher power output in a low-frequency vibration environment. Combining the Euler–Bernoulli beam theory and the D’Alembert principle, the differential dynamic equation of the doubly clamped energy harvester is derived, in which the excitation mode of axial load with pre-deformation is considered. A numerical solution of voltage amplitude and average power is obtained using the Rayleigh–Ritz method. Output power of 22.5 μW at 27.1 Hz, with the optimal load resistance being 1 MΩ, is determined by the frequency sweeping analysis. In order to power electronic devices, the converted alternating electric energy should be rectified into direct current energy. By connecting to the MDA2500 standard rectified electric bridge, a rectified DC output voltage across the 1 MΩ load resistor is characterized to be 2.39 V. For further validation of the mechanical-electrical dynamical model of the doubly clamped flexible piezoelectric energy harvester, its output performances, including both its frequency response and resistance load matching performances, are experimentally characterized. From the experimental results, the maximum output power is 1.38 μW, with a load resistance of 5.7 MΩ at 27 Hz, and the rectified DC output voltage reaches 1.84 V, which shows coincidence with simulation results and is proved to be sufficient for powering LED electronics.

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