Calibration of Laminar Flow Meters for Process Gases
John D. Wright, Thiago Cobu, Robert F. Berg, Michael R. Moldover
We calibrated three models of commercially-manufactured, laminar flow meters (LFMs) at four pressures (100 kPa, 200 kPa, 300 kPa, and 400 kPa) with five gases (N2, Ar, He, CO2, and SF6) over a 10:1 flow range using NISTs primary flow standards as references. We combined three items: (1) the calibration data acquired with N2, (2) gas-property data from NISTs database REFPROP 9.0, and (3) a physical model for each LFM that accounts for the effects of viscosity, entrance and exit effects, gas expansion, gas non-ideality, and slip. This combination predicted the calibrations for the flow of Ar, He, CO2, and SF6 with a maximum error of 0.8% for Reynolds numbers Re
, Cobu, T.
, Berg, R.
and Moldover, M.
Calibration of Laminar Flow Meters for Process Gases, Flow Measurement and Instrumentation, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=908560
(Accessed October 22, 2021)