«Automation and Informatization of the fuel and energy complex»

Methodology for calculating the relative extended uncertainty for ultrasonic transit time gas flowmeters

UDC: 681.121.89.082.4
DOI: -

Authors:

¹ National University of Oil and Gas "Gubkin University", Moscow, Russia

Keywords: gas flow measurement, ultrasonic flow meter, measurements uncertainty, accuracy assessment, calculation method, decomposition method, metrologically significant values, correlation of factors

Annotation:

Ultrasonic gas flow meters are currently widely used in the gas industry. One of the key advantages of ultrasonic flow meters (UFM) is high measurement accuracy, characterized in terms of measurement error or uncertainty. Measurement uncertainty in industry is determined according to the methodology specified in GOST 8.611-2024, but it has a number of significant drawbacks that make it impossible to assess the impact of various factors on volumetric flow readings under operating conditions. For this purpose, a detailed methodology has been developed for calculating the relative extended uncertainty of volumetric flow measurements under standard conditions of an UFM, which allows comprehensively evaluating the accuracy characteristics of an UFM. In order to simplify the general methodology for calculating uncertainty, the decomposition method was used to calculate mutually correlating estimates of metrologically significant quantities. The proof of the validity and limitations of the decomposition method for estimating the uncertainty of measuring gas flow is presented. Calculation equations are given for: volume flow under standard conditions; volume flow under operating conditions; correction of geometric parameters. The mutually correlating factors are indicated, the covariance among which should be taken into account in the calculation method. Some comments are given on the components of the relative extended uncertainty of measuring gas flow.

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