Gas Dynamic Pipe Flow Effects in Controlled Pneumatic Systems - A Simulation Study

Abstract

Electro-pneumatic modulators (EPMs) are widely used in controlled pneumatic systems. Their aim isto ensure a controlled operating pressure modulated at a high accuracy and high temporal resolution.This paper reports a computational case study representing the influence of gas dynamic pipe floweffects on the operation of a pneumatic system to be controlled by means of an EPM. The simulationhas been carried out with use of simulation software AMESim version 3.01. Given that no standardgas dynamic pipe model and electro-dynamically-relevant solenoid valve model are included in thepresent version of the simulation software, such models had to be elaborated by the authors. Thesimulation studies reveal that the self-developed gas dynamic pipe model resolves properly thewaveeffects and flow fluctuations expected from a realistic pneumatic pipe performing high velocity flow.The simulation must accurately resolve such phenomena if the computational study aims to providean aid to the design of a proper pressure control loop. It has been concluded that a gas dynamic pipemodel, covering reliably the physically possible entire Mach number range, is essential in simulationof pneumatic systems.