Abstract
Gas–Liquid two phase co-current flow in a vertical riser with an internal diameter of 127 mm was investigated in the churn flow pattern. This paper presents detailed experimental data obtained using a Wire Mesh Sensor. It shows that the most obvious features of the flow are huge waves travelling on the liquid film. Wisps, large tendrils of liquid and the product of incomplete atomisation, which had previously detected in smaller diameter pipes, have also been found in the larger diameter pipe employed here. The output of the Wire Mesh Sensor has been used to determine the overall void fraction. When examined within a drift flux framework, it shows a distribution coefficient of ∼1, in contrast to data for lower gas flow rates. Film thickness time series extracted from the Wire Mesh Sensor output have been examined and the trends of mean film thickness, that of the base film and the wave peaks are presented and discussed. The occurrence of wisps and their frequencies have been quantified.
Highlights
Flow patterns in vertical pipesGas–liquid two-phase flow has many applications in the oil and gas, chemical and nuclear industries
This paper reports on air/water churn flow in a large diameter vertical pipe employing Wire Mesh Sensors and other instrumentation
The information is presented on: (1) flow patterns and structures present; (2) mean void fraction; (3) time series of cross-section averaged void fraction, velocities and frequencies of the periodic structures found in the flow and (4) the flow rates at which wisps occur and their frequencies
Summary
Gas–liquid two-phase flow has many applications in the oil and gas, chemical and nuclear industries. Because of the infinite possibilities of distributions of the phases, researchers have tended to use flow patterns to describe the flows. Direct observation through a transparent pipe section, through a high speed camera, can allow visual and qualitative interpretation of the flow inside the pipe. This is very subjective, and in early projects such as by Bennett et al (1965), researchers formed a consensus through anonymous voting. Visual observations are problematic, because the flow at the pipe wall is often obscured by bubbles or waves on wall films, at higher velocities, meaning that it is difficult to see what is happening deep inside the pipe through this approach alone. A more objective approach is to gather signals from instruments and interpret those signals
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
