Modification of the equation for mass flow rate (mass) measurement of liquid with account of dynamic influencing factors

• Published in: Flow measurement and instrumentation Vol. 83; p. 102117
• Main Authors: Shchelchkov, A.V., Fafurin, V.A., Korneev, R.A., Tukhvatullin, R.R.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-03-2022
• Subjects: Approbation; Continuity equation; Diverter; Dynamic factors; Flow rate fluctuations; Indirect measurement method; Liquid velocity profile; Nozzle exit; Turbulent pulsations; Uncertainty budget; Liquid velocity profile; Dynamic factors; Flow rate fluctuations; Approbation; Continuity equation; Turbulent pulsations; Indirect measurement method; Nozzle exit; Diverter; Uncertainty budget
• ISSN: 0955-5986; 1873-6998
• DOI: 10.1016/j.flowmeasinst.2021.102117

The paper introduces theoretical foundations for the method of transferring units of mass and volume of liquid in the flow, mass and volumetric liquid flow rates using the indirect measurement method. The equation for measuring the mass flow rate (mass) was modified in terms of assessing the dynamic influencing factors caused by transient processes: liquid flow rate fluctuations and turbulent pulsations, unevenness of the liquid velocity profile in the nozzle exit of the diverter. The modified equation was derived from the continuity equation in physical and mathematical modeling of hydrodynamic processes of liquid flow in the nozzle exit of the diverter using mathematical statistics methods. The main uncertainty sources of calibration units with weighing devices were identified. The results of the approbation of the method of transferring units of mass and volume of liquid in the flow, mass and volumetric liquid flow rates were obtained on calibration units with weighing devices in a wide range of geometric and operating parameters. A comparison of the expanded measurement uncertainty of the calibration unit with weighing devices when transferring units of mass and volume of liquid in the flow, mass and volumetric liquid flow rates, determined using the method of indirect measurements and comparison testing with a transfer standard, was performed.
•The equation for measuring the mass flow rate (mass) was modified in terms of assessing the dynamic influencing factors caused by transient processes: liquid flow rate fluctuations and turbulent pulsations, unevenness of the liquid velocity profile in the nozzle exit of the diverter.•The modified equation was derived from the continuity equation in physical and mathematical modeling of hydrodynamic processes of liquid flow in the nozzle exit of the diverter using mathematical statistics methods.•Studies of transient processes during diverter operation were carried using a Pitot probe at the exit of a rectangular nozzle.•A comparison of the expanded measurement uncertainty of the calibration unit with weighing devices when transferring units of mass and volume of liquid in the flow, mass and volumetric liquid flow rates, determined using the method of indirect measurements and comparison testing with a transfer standard, was performed.