The transmission line method for modelling laminar flow of liquid in pipelines

Abstract

The transmission line method is a very efficient technique for dynamic modelling of flow in pipelines, and uses delay elements to represent wave propagation. In this paper, an existing transmission line method is investigated and shown to have some deficiencies. Some adjustments are proposed to avoid these deficiencies and enhance the transient and steady-state accuracy. Very good agreement is obtained between this adjusted transmission line method and an analytical model. The method has been implemented in simulations of a number of highly dynamic systems, and has been found to be robust and reliable.

Modelling Dynamic Response of Hydraulic FluidWithin Tapered Transmission Lines

“…It is important to note that for a pipeline of uniform cross section, the taper ratio would be 1, and the resulting characteristic impedance, laminar resistance, and dissipation number would reduce to the same as used in the previous models for uniform tubes [2,3].…”

“…N is the frequency-dependent friction term, commonly used in previous research defined as [1][2][3][4][5][6][7] N(x, s) = −…”

“…Computer modelling of fluid transmission lines of constant cross-sectional area is an area of hydraulics where extensive research has been performed previously as well as very recently [1][2][3][4][5][6][7]. However, the established research into the modelling of tapered transmission lines has some shortcomings which requires further study and refinement.…”

“…1, the transmission line method (TLM) is a method of modelling which uses a network of linear transfer functions and time delays to model wave propagation [1], and has had recent enhancements accurately modelling the effects of frequency-dependent friction, all while solving within the time domain [2,3]. While the TLM currently works for uniform lines of constant cross-section, it has not yet been applied to tubes of varying cross-section.…”

Modeling and testing for hydraulic shock regarding a valve-less electro-hydraulic servo steering device for ships

“…As the hydraulic shock has the wide range frequency of pulsation and the hose pipe length is comparatively long, the dynamics equation of the hose pipe is obtained by the distribution parameter modeling method [ 14 ]. …”