Application of MATLAB functions for time domain simulation of systems with lines with fluid transients

The transfer functions generated in the MATLAB working environment with algorithms are used to generate accurate rational polynomials transfer functions for a total system in which one or more lines are internal components. The approach include the distributed parameter model for the fluid transients with friction approximations and parameter modeling techniques associated with fluid transients. A least-squares curve fit algorithm named 'invfreqs' was used to formulate a rational polynomial approximation for complex transfer function in frequeny domain. The fluid transients in the lines are based on a laminar flow distributed parameter model, which includes nonlinear frequency dependent viscous friction terms and heat transfer effects in gas lines.