ULTRASONIC MEASUREMENTS OF BUBBLE SHAPE AND LIQUID FILM THICKNESS OF A TAYLOR BUBBLE RISING IN A STAGNANT WATER COLUMN
Keywords:
Multiphase FlowAbstract
The present paper reports a preliminary study of direct measurement of the equilibrium thickness of the falling film around a Taylor bubble in a stagnant water column, using the pulse-echo ultrasonic technique. The experiments were conducted in an acrylic tube of 1.8 m long with inner diameter of 25.21 mm and wall thickness of 6.8 mm. A Taylor bubble was formed by the invertion of the pipe, sealed at the ends and partially filled with water to leave an air pocket of length L0. The rising Taylor bubble was detected by a transducer located 400 mm from the top of the pipe. Ten measurements were made for each of the four channels of the ultrasonic system, using the same settings of the system parameters, totaling 40 measured bubbles. A simplied Brown's model for the thickness around a Taylor bubble was used to calculate a reference value of the parameter being measured. We found that the values directly measured by the ultrasonic technique were in good agreement with the reference value calculated and thus conclude that the pulse-echo ultrasonic technique can be applied to directly measure the thickness of thefilm around the Taylor bubbles in acrylic tubes. The errors between the experimental and the reference values were in the order of 10%.
References
De Azevedo, M. B., Faccini, J. L. H. and Su, J. Proceedings of International Nuclear Atlantic Conference, Recife, PE, Brazil. (2013)
Nogueira et al., “Flow in the Nose Region and Annular Film Around a Taylor Bubble Rising Through Vertical Columns of Stagnant and Flowing Newtonian Liquids", Chemical Engineering Science, 61, pp. 845-857, (2006).
Nicklin, D. J., Wilkes, J. O. and Davidson, J. F., “Two-Phase Flow in Vertical Tubes", Transactions of the Institution of Chemical Engineers, 40, pp. 61-68, (1962).
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Published
2015-12-04
How to Cite
de Azevedo, M. B., Faccini, J. L. H., & Su, J. (2015). ULTRASONIC MEASUREMENTS OF BUBBLE SHAPE AND LIQUID FILM THICKNESS OF A TAYLOR BUBBLE RISING IN A STAGNANT WATER COLUMN. Instituto De Engenharia Nuclear: Progress Report, (2), 57. Retrieved from https://revistas.ien.gov.br/index.php/ienprogressreport/article/view/165
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Engineering and Reactor Safety