Abstract
An error correction model for ultrasonic gas flowmeter was proposed to explore the potential of an ultrasonic flowmeter for metering gas-liquid stratified and annular flows. The gas and liquid mass flowrates could be obtained provided that the gas quality and physical prosperities were known. A single-path ultrasonic flowmeter was investigated and the error of the apparent volumetric flowrate was considered as mainly resulting from the shrinkage of the gas flow path due to the presence of a liquid phase. Fourteen void fraction models were selected for the stratified and annular flows and evaluated against experimental data. It was demonstrated that the root-mean-square error of the gas mass flowrate can be reduced from 19.0% to below 5% by employing either of Lockhart & Martinelli, Baroczy, Spedding & Chen, or Wallis void fraction models. Lockhart & Martinelli model is recommended due to its higher accuracy, simpler formulation, sounder theoretical support, and stronger immunity to pressure variation. The error correction model proposed in this work provides a basis for developing new combination measurement methods with an ultrasonic flowmeter as one component.
Highlights
Gas-liquid two-phase flow of low liquid loading attracts considerable attention due to its common occurrence in petroleum, nuclear, and chemical engineering
The gas mass flowrate is calculated based on the apparent reading from the ultrasonic flowmeter (USF) and the performance of the void fraction models is assessed by the relative error and root-mean-square error defined by (10) and (11)
WMod − WRef WRef where WMod and WRef are the gas mass flowrates calculated by the proposed error correction model and measured by the reference gas flowmeter in the experiment designated as the Author/source Wallis (1969)
Summary
Gas-liquid two-phase flow of low liquid loading attracts considerable attention due to its common occurrence in petroleum, nuclear, and chemical engineering. The natural gas usually exhibits as gas-liquid two-phase flow of low liquid loading under stratified or annular flow regime in transportation pipelines. It is still a challenge to measure the individual flowrate of the gas and liquid phases on line accurately. The metering of natural gas flow still relies on the separation approach heavily [1]. In the separation approach the natural gas flow is separated first and the gas/liquid flowrates are measured separately by traditional single-phase flowmeters, respectively. The metering uncertainty is affected by the separation efficiency significantly. In some cases a certain amount of liquid is carried into the gas line, resulting in gas-liquid two-phase flow again. The development of nonseparation approaches is a highly desired undertaking [2, 3]
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
