Bubble Formation and Liquid Weeping at an Orifice Submerged in a Liquid

Experimental Studies of Liquid Weeping and Bubbling Phenomena at Submerged Orifices

“…Although some discrepancies in the orifice size and chamber volume in the comparison are present, the trends themselves are not justifiable by conclusions drawn from corresponding investigators. For example, from the case studies involving approximately 6 mm diameter orifices, McCann and Prince's 3 experimental system conditions, compared to other investigators' conditions shown, proceed with a slightly larger orifice and smaller chamber volume which both imply a noticeably higher weeping rate and show similar or lower weeping rates than Akagi et al or Che and Chen . Of more importance to note are that each of the investigators utilized different orifice plate materials and different column diameters considered to be large enough to avoid wall effects.…”

“…Previous studies indicate the phenomenon to be only problematic for low gas velocities, below jetting velocities, or large orifice diameters greater than 2 mm. 1,2 Many investigators have modeled the weeping behavior as an aftereffect of single-bubble formation 3,4 and/ or the pressure fluctuations within the plenum. 1 However, none of these studies attempt to account for the weeping coupled effects with bubble formation detachment or pressure fluctuations both above and below the orifice plate, nor do these previous studies share a high degree of agreement with the weeping rate trend and the precise effects of system conditions, such as the chamber volume or column diameter, on the liquid weeping rate.…”

“…For example, from the case studies involving approximately 6 mm diameter orifices, McCann and Prince's 3 experimental system conditions, compared to other investigators' conditions shown, proceed with a slightly larger orifice and smaller chamber volume which both imply a noticeably higher weeping rate and show similar or lower weeping rates than Akagi et al 1 or Che and Chen. 2 Of more importance to note are that each of the investigators utilized different orifice plate materials and different column diameters considered to be large enough to avoid wall effects. However, these assumed benign changes may, in part, be the cause for such deviations.…”

“…A consequence of utilizing this simple design is the undesirable presence of liquid weeping during operation that can eventually lead to an increase in pressure drop across the distributor plate and abnormal bubbling behavior. Previous studies indicate the phenomenon to be only problematic for low gas velocities, below jetting velocities, or large orifice diameters greater than 2 mm. , …”

The Influence of Liquid Head and Liquid Circulation on Weeping Rates at a Submerged Orifice

“…Che and Chen [10], studied the influence of orifice diameter, orifice plate thickness and gas flow rate on weeping rate, at a submerged orifice. The water level was kept at a constant value of 42 cm throughout the experiments and no liquid head effects on weeping were studied.…”