KRISS high-pressure gas flow standard system

摘要

1. A high-pressure gas flow standard system of 10 000 m~3/h was developed for the primary standard calibration and its overall uncertainty was estimated as ± 0.05%. 2. The magnitude of random error is governed by the sensitivity setting of the weighing scale. With the sensitivity of 5 g, more than 25 kg of air has to be weighed to be within a ± 0.02% uncertainty limit. 3. Uncertainty in air collection time measurement as well as pressure and temperature stability of the system have a systematic effect on the primary calibration results. 4. Discharge coefficients of sonic nozzles satisfactorily agreed with the values suggested in the relevant ISO documents.