An experimental investigation on the effect of viscosity on bubbles moving in horizontal and slightly inclined pipes

作者：Losi Gianluca; Poesio Pietro^*

来源：Experimental Thermal and Fluid Science, 2016, 75: 77-88.

DOI：10.1016/j.expthermflusci.2016.01.010

• Drift velocity
• High viscosity oils
• Benjamin bubble

The motion of long bubbles in horizontal and slightly inclined pipes is a thoroughly investigated phenomenon. However, few results are available in literature for the drift velocity of a gas bubble in viscous liquids.
The aim of this study is to experimentally analyse the effect of viscosity on the drift velocity of an air bubble in horizontal and inclined pipes. Two different measurement techniques are used: five capacitance probes are placed along the pipe to monitor the velocity evolution and image analysis is used to measure the bubble front velocity at two different distances from the outlet. The results of the measurements show that for horizontal case, as opposite to Benjamin (1968), the bubble drift velocity is not constant while the front displaces along the pipe and, in general, the viscosity slows down the propagation rate of the bubble. Finally, two drift velocity closure equations are tested with collected data.

• 出版日期2016-7