Flow field around growing and rising vapour bubble by PIV measurement

Abstract

A study on flow field measurement around growing and rising vapour bubbles by use of PIV technique is presented. Bubbles were generated from single artificial cavities. Experiments have been conducted with saturated boiling of distilled water at atmospheric pressure. In the experiment fluid velocity field surrounding the bubbles was visualized by use of polyamide tracer particles and a sheet of a YAG pulse laser beam. The images were recorded with a cross-correlation CCD-camera. It has been shown that for lower heat flux density bubble growths in an almost quiescent bulk of liquid. For higher heat flux density the train of bubbles creates a vapour column with strong wake effect. Maximum liquid velocity recorded is approximately equal to the terminal velocity of bubble rising in a stagnant liquid.

CFD for Subcooled Flow Boiling: Parametric Variations

“…Probably the most relevant source is Han and Griffith [34] who in some "rough" experiments determined the hydrodynamic disturbance caused by liing a spherical particle from a horizontal surface and found that it has a range of twice the size of the particle. A similar size has been claimed by Cieslinski et al [35] from PI� measurement of the �ow �eld around departing bubbles, although the quality of the images presented is rather poor. Since = 1 corresponds to the case where the whole surface is under the in�uence of bubbles, as calculated by (10) has to be limited to values smaller than this limit.…”

Review of Subcooled Boiling Flow Models

“…Probably the most relevant source is Han and Griffith (1965) who in some "rough" experiments determined the hydrodynamic disturbance caused by lifting a spherical particle from a horizontal surface and found that it has a range of twice the size of the particle. A similar size has been claimed by Cieslinski (2005) from PIV measurement of the flow field around departing bubbles, although the quality of the images presented is rather poor.…”

The flow induced by a jellyfish

“…The vortex ring generated inside the skirt is similar to a vortex ring behind a rising vapour bubble observed by Cieslinski et al (2005). The ratio of increment of the circulation to that of the initial one is 1.06 by using the values of 4.9 mm (0.11R), the diameter of the vortex core, and 12.3 mm (0.27R), the diameter of the vortex ring, in this experiment.…”