We review primary and working gas flow standards that are used to calibrate gas flow
meters. For each type of primary standard, we describe the principles and practical …

The body temperature of critical flow nozzle is cooled by expanding cold gas. Subsequently,
the thermal boundary layer and throat area are influenced by the conjugate heat transfer at …

In 2016, PTB introduced a function for the representation of the discharge coefficient c D of
critical flow venturi nozzles (CFVN)(versus the Reynolds number Re) which covers the …

We improve the usefulness of small (diameter< 10 mm) critical flow venturis (CFVs) as
transfer standards for gas flow by measuring and explaining how their discharge coefficients …

Sonic nozzles are widely used as flow measurement and transfer standard. The thermal
effect of sonic nozzle is significant at low Reynolds number. It includes two correction factors …

The expansion of the gas through a critical flow Venturi nozzle (CFVN) leads to a 50° C
temperature drop of the gas at the nozzle throat. The body of CFVN is also cooled, which …

For the sonic nozzles, the discharge coefficient (C d) is an essential parameter of flow
characteristics, which is obviously influenced by the thermal effect determined by the nozzle …

To investigate the influence of complex body temperature distribution, especially the
temperature drop near the throat on the discharge coefficient Cd of sonic nozzles, an …

To improve the measurement accuracy of sonic nozzle, the complex thermal effect in sonic
nozzles were investigated. As the essential characteristic of thermal effect, the steady and …

For almost 50 years, flow measurement applications using critical flow venturis (CFVs) have
relied exclusively on the critical flow function (* C) to correct for real gas effects. This work …