Modeling Temperature Effects on a Coriolis Mass Flowmeter
Fabio O. Costa, Jodie Gail Pope, Keith A. Gillis
Coriolis mass flowmeters are known to be stable, have low uncertainty (± 0.1 %), and are insensitive to fluid properties. This meter type is used for many applications, including as transfer standards for proficiency testing and liquified natural gas (LNG) custody transfer. The meter's flow tubes are constructed of materials that can significantly affect the meter's accuracy as the pressure and temperature of the fluid inside them changes. Stainless steels are commonly used for flow tube construction due to their corrosion resistance. We developed a model to explain the temperature dependence of a Coriolis meter down to cryogenic temperatures. We tested our model over the range of 285 K to 318 K in this work. The temperature dependence predicted by the model agrees with experimental data within ± 0.1 %, well within the model uncertainty of 3.5 % (k = 2) that is dominated by the uncertainty in the values of E and G from the literature. We disabled the manufacturer's temperature compensation in a single, dual – tube, 5 cm diameter Coriolis meter to test for the accuracy of our model. The manufacturer's supplied pressure correction was verified to assure all observed deviations were due to temperature effects on the meter. The goal of this work is to: 1) quantify the errors due to inaccurate temperature corrections and thereby enable more accurate use of the meter as a transfer standard, and 2) allow Coriolis meters to be calibrated in water and used for LNG transfer with little loss of accuracy. At temperatures below 100 K, the Young's modulus and shear modulus of stainless steels display nonlinear behavior. Therefore, our model includes corrections for these phenomena. Here, basic concepts of Coriolis flowmeters will be presented, and correction coefficients will be proposed that are valid down to 5 K based on literature values of material properties.
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Modeling Temperature Effects on a Coriolis Mass Flowmeter, Flow Measurement and Instrumentation, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929881
(Accessed September 19, 2021)