Carvalho, R.D.M.Venturini, O.J.Neves-Jr, F.Arruda, L.V.R.França, F.A.2014-07-182014-07-182007Carvalho, RDM, Venturini, OJ, Neves-Jr, F, Arruda, LVR & França, FA 2007, 'Experimental study of ultrasonic characteristics in air-water bubbly flows', Paper presented to the 5th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 1-4 July 2007.9781868546435http://hdl.handle.net/2263/40877Paper 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.6 pagesPDFenUniversity of PretoriaUniversity of PretoriaUltrasonic techniquesUltrasonic signals characteristicsCharacterization of two-phase flowsMultiphase flowsTransit timePresentation