Dynamic Behavior of Micro-droplets in Liquid Dielectric and Its Effect on Partial Discharge

Microbubble floating in liquid dielectric and subjected to an electric field may initiate partial discharge (PD). This paper studies the parameters that affect the initiation through a computer simulation. This study inspects how the type of gas inside the microbubble, the size of the microbubble, distance from an electric field, Eo, source and, the magnitude of source’s voltage affect the start of PD. For a prolate spheroid shape, there is an important parameter called ‘c’. This ratio is between the radius of the microbubble polar (‘a’) and the radius of the equator (‘b’). At constant Eo and c, different gases will initiate PD at different distances from source due to differences in a localised electric field inside the microbubble (Emax). Emax is one of the important factors for PD initiation. It is interesting to report that if the ‘a’ and ‘b’ values are chosen so that ‘c’ will be constant, changes in Emax are insignificant. On the other hand, changes in ‘c’ will result in significant changes in Emax. Finally, changes in source’s voltage certainly affect the Emax.

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Dynamic behavior of surface charge distribution during partial discharge sequences

IEEE Transactions on Dielectrics and Electrical Insulation ◽

10.1109/tdei.2013.6508765 ◽

2013 ◽

Vol 20 (2) ◽

pp. 612-619 ◽

Cited By ~ 36

Author(s):

Kai Wu ◽

Cheng Pan ◽

Yongpeng Meng ◽

Yonghong Cheng

Keyword(s):

Surface Charge ◽

Charge Distribution ◽

Dynamic Behavior ◽

Partial Discharge ◽

Surface Charge Distribution

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Modeling of the Partial Discharge Process in a Liquid Dielectric: Effect of Applied Voltage, Gap Distance, and Electrode Type

Energies ◽

10.3390/en6020934 ◽

2013 ◽

Vol 6 (2) ◽

pp. 934-952 ◽

Cited By ~ 14

Author(s):

Wenxia Sima ◽

Chilong Jiang ◽

Paul Lewin ◽

Qing Yang ◽

Tao Yuan

Keyword(s):

Applied Voltage ◽

Partial Discharge ◽

Liquid Dielectric ◽

Discharge Process ◽

Dielectric Effect

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Unraveling the Dynamic Behavior of Ecological Models: Algebraic, Geometric and Numerical Methods of Analysis

Comments® on Theoretical Biology ◽

10.1080/08948550213853 ◽

2002 ◽

Vol 7 (3) ◽

pp. 155-176

Author(s):

J. V. Greenman

Keyword(s):

Numerical Methods ◽

Dynamic Behavior ◽

Ecological Models ◽

Methods Of Analysis

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Use of open-ended coaxial line sensor with a laminar or liquid dielectric backed by a conducting plane

IEE Proceedings H Microwaves Antennas and Propagation ◽

10.1049/ip-h-2.1992.0033 ◽

1992 ◽

Vol 139 (2) ◽

pp. 179 ◽

Cited By ~ 10

Author(s):

S. Jenkins ◽

A.G.P. Warham ◽

R.N. Clarke

Keyword(s):

Coaxial Line ◽

Liquid Dielectric ◽

Conducting Plane

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Multiscale analysis of the effect of grain size on the dynamic behavior of microalloyed steels

DYMAT 2009 - 9th International Conferences on the Mechanical and Physical Behaviour of Materials under Dynamic Loading ◽

10.1051/dymat/2009142 ◽

2009 ◽

Cited By ~ 1

Author(s):

A. K. Zurek ◽

K. Muszka ◽

J. Majta ◽

M. Wielgus

Keyword(s):

Grain Size ◽

Dynamic Behavior ◽

Multiscale Analysis ◽

Microalloyed Steels

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Ball bearing turbocharger vibration management: application on high speed balancer

Mechanics & Industry ◽

10.1051/meca/2020091 ◽

2020 ◽

Vol 21 (6) ◽

pp. 619

Author(s):

Kostandin Gjika ◽

Antoine Costeux ◽

Gerry LaRue ◽

John Wilson

Keyword(s):

Dynamic Behavior ◽

High Speed ◽

Internal Combustion Engines ◽

Ball Bearing ◽

Squeeze Film ◽

Design And Technology ◽

Squeeze Film Damper ◽

Damping Coefficients ◽

Bearing Loads ◽

Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

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