Traceable profile and roughness measurements inside small sonic nozzles with the Profilscanner to analyse the influence of inner topography on the flow rate characters

Abstract

The Profilscanner developed by PTB enables traceable roughness and profile measurement of high aspect ratio structures with diameters down to 50 μm. For the first time the inner surfaces of small sonic nozzles with diameters in the submillimetre range could be successfully characterized. The comparison between these topographical measurements and corresponding mass flow rate experiments confirms the assumption that the topography of the inner surfaces has a strong influence on the mass flow rate of small nozzles.