Analysis of Dynamics of Pneumatic Transmission Line Considering the Change of Polytropic Exponent

Abstract

A method of analyzing the dynamics of the pneumatic transmission line is presented in this. paper by using the polytropic exponent n (jω) which is the function of frequency ω of the pressure change.
The basic differential equations are given which describe the dynamic properties of the transmission line by taking into consideration the mass balance, the energy balance, the momentum balance, the state equation of fluid and the energy balance of wall.
These equations are linearized and Laplace transformed. The transfer function of the pneumatic transmission line is obtained by applying the boundary condition which is given by the same relations of fluid and wall at the lumped terminal volume.
Frequency response characteristics derived from this method are compared with the experimental results, and good agreements have been obtained.