Blow-Down Calibration of a Large Ultrasonic Flow Meter

Published

April 21, 2021

Author(s)

Aaron Johnson, Eric Harman, Joey Boyd

Abstract

Oil and gas production industries use large (diameter > 0.8 m) ultrasonic flow meters (USMs) to measure exhaust gas from flare stacks, emissions from smokestacks, flow of natural gas, etc. Since most flow laboratories do not have compressors with sufficient flow capacity ( > 10 kg/s) to calibrate large flow meters, calibrations are performed using the blow-down method where flow is generated by discharging high pressure tanks, leading to significant flow transients. We used an array of critical flow venturis (CFVs) in a blow-down facility to calibrate a large (D = 89.5 cm) 8-path ultrasonic flow meter. The flow transients associated with the blow-down process caused large spatial and temporal variations in temperature that dominated (40 % to 67 %) the uncertainty budget. Our uncertainty analysis accounts for transient-generated uncertainties and provides guidelines for improving blow-down calibrations of large flow meters.

Citation

Flow Measurement and Instrumentation

Volume

77

Pub Type

Journals

Download Paper

https://doi.org/10.1016/j.flowmeasinst.2020.101848

Local Download

Keywords

Blow-Down Calibration, Large Ultrasonic Flow Meter, Transient Flow Calibration, Critical Flow Venturis

Citation

Johnson, A. , Harman, E. and Boyd, J. (2021), Blow-Down Calibration of a Large Ultrasonic Flow Meter, Flow Measurement and Instrumentation, [online], https://doi.org/10.1016/j.flowmeasinst.2020.101848, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=929354 (Accessed October 25, 2025)