Relations débit-pertes de charges en pneumatique

Flow-pressure drops relationships for pneumatics

CETIM, 52 avenue Félix Louat, 60300 Senlis

Abstract

In order to optimise the performances of the new generation of pneumatic proportional components, a good knowledge of the flow-pressure drops relationships within those components is necessary.

The ISO 6358 standard introduces two coefficients to characterize both the flow regimes of compressed air in pneumatic lines viz: subsonic flow and sonic flow. The crilical pressure ratio (P down/P up) for a given industrial pneumatic component depends essentially of its internal design. That ratio is of paramount importance because it determines pressure ratio for which the flow regimes change and consequently the flow-pressure drops relationships. If it is about 0.5 for correctly sized nozzles it may be only 0,15 for a real pneumatic component. This paper will emphasize the avantages and drawbacks of this ISO characterisation, and the test methods to be used ta determine them experimentally.