scholarly journals Lumped Parameter Approximation for Pipeline Dynamics of Hydraulic Circuits in Digital Simulation. 1st Report. Approximation for the Lossless Line Model.

1994 ◽  
Vol 25 (1) ◽  
pp. 118-123
Author(s):  
Ikuro IIMURA ◽  
Satoru HAYASHI ◽  
Shoji MURAYAMA
Keyword(s):  
Digital Simulation ◽  
Line Model ◽  
Lumped Parameter ◽  
Parameter Approximation ◽  
Hydraulic Circuits

Modelling of Electrohydraulic Systems with Transmission Lines using Modal Approximations

1988 ◽  
Vol 202 (3) ◽  
pp. 153-163 ◽  
Author(s):  
J Watton
Keyword(s):  
Transmission Lines ◽  
Method Of Characteristics ◽  
Digital Simulation ◽  
Time Domain Analysis ◽  
Domain Analysis ◽  
Frequency Domain Analysis ◽  
Specific Form ◽  
Lumped Parameter ◽  
Good Comparison ◽  
Distributed Friction

The method of modal approximation to the distributed friction transmission line functions via frequency-domain analysis is briefly discussed. A specific form is then derived which allows time-domain analysis to be easily pursued using a digital simulation package approach. The method is applied to a highly non-linear servo-valve controlled motor system and a good comparison between experiment and theory is shown. A comparison is also made with previous work using the method of characteristics, and natural frequency predictions are also compared with some common lumped parameter approximations.

A Method of Characteristics Based Coupled Pump/Line Model to Predict Noise Sources of Hydrostatic Transmissions

2009 ◽  
Author(s):  
Richard Klop ◽  
Andrea Vacca ◽  
Monika Ivantysynova
Keyword(s):  
Method Of Characteristics ◽  
Numerical Approach ◽  
Noise Sources ◽  
Line Model ◽  
Lumped Parameter ◽  
Lumped Parameter Models ◽  
Pressure Ripple ◽  
Flow Oscillations ◽  
Hydrostatic Transmissions ◽  
Parameter Approach

This study is a part of a larger research project to predict noise sources of hydrostatic transmissions and investigating new methods for designing quieter systems. The aim of this study is to validate the developed model describing pump dynamics coupled with effects of a connecting line, thus validating a coupled pump-motor-line model for hydrostatic transmissions. This paper illustrates a numerical approach for evaluating pressure and flow oscillations generated by a hydraulic pump coupled with a connecting line. The presented model describes pump dynamics using a lumped parameter approach as well as one-dimensional unsteady compressible fluid flow by means of method of characteristics (MOC). Several lumped parameter models have been developed for hydraulic pumps and motors and the method of characteristics has been applied for many applications; however, the presented model uniquely utilizes both approaches and considers influence of pump dynamics and propagating pressure and flow pulsations throughout the line. Measurements of pressure ripple in the line at two different points were carried out at various loading conditions to validate the developed model. Comparisons between measurements, the developed model, and another more simplified model were conducted. Results indicate a reasonable match between the developed model and measurements as well as the importance of considering a line model based on method of characteristics.

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