The National Institute of Standards and Technology (NIST) is working to characterize temperature effects on flow meters used in cryogenic liquids, such as liquified natural gas (LNG) and liquid oxygen. This is important because NIST’s cryogenic liquid flow standard was decommissioned in 2020, leaving limited options for meter calibration in cryogenic flows.
To address this challenge, NIST’s Fluid Metrology Group is developing a physical model based on Young’s modulus and Poisson’s ratio to predict temperature effects on Coriolis meters. The model uses the resonance frequency of the flow tube(s) and literature values for temperature dependence of construction material properties.
The group validated their model using NIST’s 15 kg/s Liquid Flow Standard (LFS) and data from the decommissioned cryogenic flow facility. They tested the model over a temperature range of 285 K to 318 K with an experimental agreement within ± 0.08%, and a model uncertainty of 0.16% at the 95% confidence level.
Future work includes analyzing Coriolis meters at liquid nitrogen temperatures (~77 K), and adding a heater/chiller to the 15 kg/s LFS to actively control water temperature between 10-40°C. This will allow research on temperature effects across multiple meter types and reduce calibration variability.
Source: https://www.nist.gov/programs-projects/temperature-sensitivity-liquid-flow-meters
Keywords: Temperature effects, Coriolis flow meters, Cryogenic liquids
