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The Performance of Transit Time Flowmeters in Heated Gas Mixtures



John D. Wright


An ultrasonic transit time flowmeter was tested over Reynolds numbers from 1000 to 100,000 in a calibration facility that generates gas flows with controlled temperature and composition. The gas mixtures were composed of air, nitrogen, carbon dioxide, water vapor, and argon and the mixture temperature ranged from 290 to 450 K. The test program was conducted to determine the sensitivity of the flowmeter output to gas composition and temperature and to find the appropriate dimensionless quantities for the presentation of calibration results. Plots of discharge coefficients versus Reynolds number collapse the data well for all of the conditions tested. Comparisons between the experimentally measured discharge coefficients and those predicted by computer models using postulated velocity profiles are presented, and they show good qualitative agreement. The effects of thermal expansion on sound path length and pipe diameter were significant over the tested temperature range.
Proceedings Title
1998 ASME Fluids Engineering Division Summer Meeting
Conference Dates
June 21-25, 1998
Conference Title
Proceedings of the FEDSM '98


discharge coefficient, flowmeter, Reynolds number, stratification, thermal expansion, transit time, ultrasonic


Wright, J. (1998), The Performance of Transit Time Flowmeters in Heated Gas Mixtures, 1998 ASME Fluids Engineering Division Summer Meeting, [online], (Accessed April 21, 2024)
Created June 1, 1998, Updated February 17, 2017