Calculation of the flow-rate measurement uncertainty by means of Pitot tubes using the Monte Carlo Method

L. L. Martins, A. S. Ribeiro, J. Alves e Sousa

Abstract

This paper is dedicated to the flow-rate measurement uncertainty calculation, considering the use of Pitot tubes inside closed conduits as the applied measurement method, according to the guidelines and procedures established by the current ISO 3966 standard. The performed study aims the comparison between measurement uncertainties obtained by the conventional error approach mentioned in the method’s standard and the results obtained from the application of the Monte Carlo Method (MCM). Using the same input data, a difference of 0,3% was obtained between the 95% relative expanded measurement uncertainties. The obtained probability density function of the compressibility correction factor showed a non-Gaussian asymmetric shape, however, not affecting the remaining quantities in the uncertainty propagation chain. The Pitot tube’s calibration factor and the turbulence and high frequency fluctuations were identified as the main uncertainty contributions for the combined measurement uncertainties.

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IMEKO-TC9-2019-092.pdf

DOI

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IMEKO TC

TC9 - Flow Measurement

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