Modelling of fluid power transmission systems

The mathematical modelling of fluid power transmission systems involves solving a system of differential equations and addressing the problems generated by transient pressure propagation. The main difficulties in modelling pressurised, fluid pipelines arise from the complex interactions involving boundary conditions, reflections and non-linear behaviour. This paper presents a new method of modelling pipeline systems that provides an accurate transient response of the system incorporating a frequency-dependent fluid friction term. The modelling method employed is based upon distributed-lumped parameter modelling techniques which enable the inclusion of a wide variety of non-linear effects. The model comprises a distributed element representing the pressure and flow rate through out the length of the pipeline and a lumped element that represents the boundary conditions at the pipeline exit. The simulation results for the system are compared with experimental data validating thereby the analytical procedures proposed.