The contribution of varying shear stress to the uncertainty in gravimetric gas mass flow measurements

Sampo Sillanpää, Martti Heinonen

    Research output: Contribution to journalArticleScientificpeer-review

    1 Citation (Scopus)

    Abstract

    The effect of natural convection on the uncertainty calculation of the MIKES dynamic gravimetric gas mass flow measurement system (DWS) is studied in this paper. The magnitude of the uncertainty component due to varying shear stress rate at the wall of the cylinder is studied theoretically at two different varying temperature models. Based on the obtained results, the contribution of the component may be significant, if the temperature difference between the wall of a gas cylinder and ambient air increases 1 K during one measurement cycle. Then the contribution of the shear stress can be above 92% of the combined standard uncertainty at the gas mass flow rate 0.1 mg s−1. Correspondingly, the contribution at the same temperature difference is below 1% at the mass flow rate 625 mg s−1. Applying the Monte Carlo uncertainty estimation method, the assumption of independent variables was shown to be reasonable.
    Original languageEnglish
    Pages (from-to)249-255
    Number of pages7
    JournalMetrologia
    Volume45
    Issue number2
    DOIs
    Publication statusPublished - 2008
    MoE publication typeA1 Journal article-refereed

    Fingerprint Dive into the research topics of 'The contribution of varying shear stress to the uncertainty in gravimetric gas mass flow measurements'. Together they form a unique fingerprint.

    Cite this