Contribution to Calculation of Switching Overvoltages Originated by Line Energizing in the Networks with Lumped Parameters

2006 ◽  
Author(s):  
S. Skuletic ◽  
V. Radulovic
Keyword(s):  
Lumped Parameters

scholarly journals Recent Developments in the Modelling of Transformer Windings

Energies ◽  
2021 ◽  
Vol 14 (10) ◽  
pp. 2798
Author(s):  
Konstanty M. Gawrylczyk ◽  
Szymon Banaszak
Keyword(s):  
Literature Review ◽  
Research And Development ◽  
Frequency Response ◽  
Input Data ◽  
Recent Developments ◽  
Modelling Techniques ◽  
Lumped Parameters ◽  
Wave Phenomena ◽  
Modelling Methods ◽  
Direct Calculations

The paper provides a review of the modelling techniques used to simulate the frequency response of transformer windings. The aim of the research and development of modelling methods was to analyze the influence of deformations and faults in the windings on the changes in the frequency response. All described methods are given with examples of the modelling results performed by the authors of this paper and from literature sources. The research is prefaced with a thorough literature review. There are described models based on lumped parameters with input data coming from direct calculations based on the winding geometry and obtained from FEM modelling software and models considering the wave phenomena in the windings. The analysis was also performed for practical problems in winding modelling: the influence of windings other than the modelled one and the influence of parallel wires in a winding.

Numerical simulation of a catalytic reaction dynamics in a kinetic region

1984 ◽  
Vol 49 (1) ◽  
pp. 170-178 ◽  
Author(s):  
Karel Klusáček
Keyword(s):  
Experimental Data ◽  
Numerical Simulation ◽  
Catalytic Reaction ◽  
Reaction Dynamics ◽  
Methanol Dehydration ◽  
Balance Equations ◽  
Kinetic Region ◽  
Lumped Parameters ◽  
Relaxation Curves ◽  
Calculation Procedures

The method of numerical simulation of a catalytic system dynamics with lumped parameters is reported. Appropriate balance equations have been derived and suitable calculation procedures are discussed. Numerical example of simulation of the catalytic methanol dehydration dynamics is presented and calculated relaxation curves are compared with experimental data obtained earlier.

scholarly journals Prediction of Vehicle Crashworthiness Parameters Using Piecewise Lumped Parameters and Finite Element Models

Designs ◽  
2018 ◽  
Vol 2 (4) ◽  
pp. 43 ◽  
Author(s):  
Bernard B. Munyazikwiye ◽  
Dmitry Vysochinskiy ◽  
Mikhail Khadyko ◽  
Kjell G. Robbersmyr
Keyword(s):  
Finite Element ◽  
Severity Index ◽  
Finite Element Models ◽  
Element Analysis ◽  
Computational Costs ◽  
Nonlinear Springs ◽  
Crash Testing ◽  
Lumped Parameters ◽  
Crashworthiness Analysis ◽  
Vehicle Crashworthiness

Estimating the vehicle crashworthiness experimentally is expensive and time-consuming. For these reasons, different modelling approaches are utilised to predict the vehicle behaviour and reduce the need for full-scale crash testing. The earlier numerical methods used for vehicle crashworthiness analysis were based on the use of lumped parameters models (LPM), a combination of masses and nonlinear springs interconnected in various configurations. Nowadays, the explicit nonlinear finite element analysis (FEA) is probably the most widely recognised modelling technique. Although informative, finite element models (FEM) of vehicle crash are expensive both in terms of man-hours put into assembling the model and related computational costs. A simpler analytical tool for preliminary analysis of vehicle crashworthiness could greatly assist the modelling and save time. In this paper, the authors investigate whether a simple piecewise LPM can serve as such a tool. The model is first calibrated at an impact velocity of 56 km/h. After the calibration, the LPM is applied to a range of velocities (40, 48, 64 and 72 km/h) and the crashworthiness parameters such as the acceleration severity index (ASI) and the maximum dynamic crush are calculated. The predictions for crashworthiness parameters from the LPM are then compared with the same predictions from the FEA.

Influence of condenser microphones on phase measurements in photoacoustics at low pressure

1986 ◽  
Vol 64 (9) ◽  
pp. 1111-1115
Author(s):  
G. Louis ◽  
F. Lepoutre ◽  
J. P. Monchalin
Keyword(s):  
Phase Shift ◽  
Photoacoustic Signal ◽  
Low Pressure ◽  
Response Magnitude ◽  
Phase Measurements ◽  
Condenser Microphone ◽  
Slip Effects ◽  
Shift Response ◽  
Lumped Parameters

Condenser microphones used as photoacoustic signal detectors exhibit a phase-shift response that depends on both the nature and the pressure of the ambient filling gas. In this paper, we develop a lumped-parameters model of the microphone damping in which the approximations are thoroughly discussed. This model, after taking into account gas-slip effects on the surfaces of the condenser cartridge plates, is shown to accurately describe the response (magnitude and phase) of a commercial condenser microphone (Brüel and Kjaer 4144) for frequencies below 2.2 kHz and ambient pressures between 1.5 × 103 and 6 × 104 Pa.

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