Optical probe for local void fraction and interface velocity measurements

Abstract

In view of the importance of obtaining unsteady local void fraction and interface velocities in liquid-vapor two-phase flows, an optical probe with a controlled tip geometry was developed and is described. In order to minimize the disturbances caused to the flow field by the presence of the probe, its dimensions have been miniaturized. The electronic and hydrodynamic responses of the probe were investigated experimentally. The probe was found to be sensitive to both the interface velocities and the phase present at the probe tip. A possible explanation for the behavior of the probe is presented. Within the velocity range checked and with proper calibration, the optical probe described can be used to determine both local void fractions and interface velocities.

Two-phase flow structure of sheet cavitation

“…Different types of local probe have been developed for determining the phase density function in gas-liquid flows. Among these are impedance measurements ͑Nassos and Bankoff; 12 Serizawa et al 13 ͒, the capacitive method ͑Gunn and Al-Doori 14 ͒, hot wire technique ͑Bremhorst and Gilmore 15 ͒, temperature measurements ͑Delhaye et al 16 ͒ and optical techniques ͑Abuaf et al, 17 Cartellier and Achard 18 ͒. In the recent past, new nonintrusive techniques have appeared: X-ray scattering techniques ͑Han and Wesser 19 ͒, nuclear magnetic resonance ͑Javelot et al 20 ͒, and the grating velocimeter-granulometer ͑Cartellier 21 ͒.…”

“…Danel and Delhaye developed a Ushaped probe with a thickness of 0.1 mm ͑Galaup, 23 Danel 24 ͒. Abuaf et al, 17 Hinata et al 25 fused together two fibers at one end and polished it, thus forming an included angle of 90°at the probe tip. Measurement in corrosive or erosive environments led Vince et al 26 and Stutz and Reboud 27 to use optical fibers wrapped in metal tubes and equipped with glued diamond or sapphire tips at their end.…”

Mesure locale dans les écoulements diphasiques : développements récents des sondes optiques

“…Sondes thermiques a) Microthermocouples [4,19] Une sonde comportant un microthermocouple (20 pm) permet la mesure locale de la température. Si la jonction de ce thermocouple n'est pas isolée du fluide, on peut détecter la phase en présence par une mesure de conductivité.…”

Bubble Dynamics in 2d Bubble Column: Comparison Between High-Speed Camera Imaging Analysis and 4-Point Optical Probe

“…Research on bubble columns covers a wide range, including gas holdup (i.e., Fair et al, 1962;Heijnen and Van't Riet, 1984;Kawase and Moo-Young, 1987;Krishna et al, 1991;Ruzicka et al, 2001;Saxena and Rao, 1991;Shah et al, 1982), bubble characteristics (i.e., Abuaf et al, 1978;Guet et al, 2003;Lin and Fan, 1999;Luther et al, 2004;Manera et al, 2009), and interfacial area (i.e., Delhaye and Bricard, 1994;Kataoka et al, 1986;Kiambi et al, 2001;Manera et al, 2009;Revankar and Ishii, 1993). Although bubble columns are commonly used in industry.…”