Electro-pneumatic modulators (EPMs) are widely used in controlled pneumatic systems.
Their aim is to 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 flow effects on the operation of a pneumatic system
to be controlled by means of an EPM. The simulation has been carried out with use
of simulation software AMESim version 3.01. Given that no standard gas dynamic pipe
model and electro-dynamically-relevant solenoid valve model are included in the present
version of the simulation software, such models had to be elaborated by the authors.
The simulation studies reveal that the self-developed gas dynamic pipe model resolves
properly the wave effects 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 provide an aid to the design of a proper pressure
control loop. It has been concluded that a gas dynamic pipe model, covering reliably
the physically possible entire Mach number range, is essential in simulation of pneumatic
systems.
