Measurement of Interfacial Parameters of Single Taylor Bubbles Rising in Closed Vertical and Slightly Inclined Tubes Using Ultrasonic and Visualization Techniques.
Marcos Bertrand de Azevedo1; Douglas dos Santos2; Nathalia Nunes Araujo2; Pedro Andrade Maia Vinhas3; José Luiz Horacio Faccini1; Jian Su3
1 Instituto de Engenharia Nuclear (IEN/CNEN); 2 Departamento de Engenharia Nuclear (DEN/Poli/UFRJ); 3 Programa de Engenharia Nuclear (PEN/COPPE/UFRJ)
doi:10.20906/CPS/COB-2015-0479
Resumo
The present paper reports an experimental study of single Taylor bubbles rising in water-glycerin mixtures in vertical and slightly inclined tubes. The velocities and lengths of the rising bubbles were measured by using the pulse-echo ultrasonic technique and a high speed video camera. The bubble profiles and the thicknesses of the liquid films around the bubbles were measured by the ultrasonic technique. The inclination angles studied were 0, 2.5, 5, 7.5, 10 and 15 degrees from the vertical position. It was observed, for all liquids studied, that the bubble velocity decreased and the film thickness increased with increasing viscosity. Furthermore, the bubble velocity increased with increasing inclination angle. The measurements also indicated that the inclination angle influenced the length of bubbles formed from the same air volume, especially for those rising in higher viscosity liquids.
Palavras-chave: Ultrasonic Technique; Visualization Technique; Rising Velocity; Liquid Film Thickness; Taylor Bubble; Stagnant Liquid