Paper presented at the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July, 2007.
In the oil industry there is a need to determine the dispersed
phase holdup in multiphase flows using noninvasive, fast
responding techniques; ultrasonic techniques apparently can
fulfill these requirements. In this regard, the proposed paper
analyzes the ultrasonic signals obtained through vertical,
upward air-water flows in the zero to 14% void fraction range.
Initially, the experimental apparatus and the flow patterns
observed are discussed. Next follows a discussion of the
ultrasonic signals characteristics and the trends in the transit
time and attenuation. A new transit time definition is proposed
that could be used for the characterization of two-phase flows.