Microbubble Generation Using High Turbulent Intensity Flow

Abstract

In this paper, a new method for microbubble generation independent of porous media has been introduced. The approach used in the microbubble generator is based on high turbulent intensity rotational flow. At first, a simple cylindrical model is investigated experimentally. In the model, water enters the device via six diagonal nozzles and mixes with air coming from six holes at the bottom of the device. Passing a rotational trace around central motionless rod, air particles are broken up to tiny bubbles. Size of bubbles is measured and bubbles smaller than 1mm in diameter were found. Finally, improved microbubble generator with the similar mechanism has been introduced. Internal flow passes longer trajectory around the central rotating hub because of its design characteristic that let it rotate by inlet water excitation. Bubbles with diameters less than 300 microns are generated by this method. Size of bubbles is measured experimentally in different void fractions for different outlet gap size. Outlet flow gap changes from 20mm to 8mm and 3mm in three experiments. The best result is observed in the third experiment at which microbubbles smaller than 100 micron are observed. The desirable bubbles’ size is achieved at void fraction of 15% that could be increased up to 60%.

Improvement of a Microbubble Generator's Performance Via Reliance on Fluid Dynamics Characteristics

“…1). The size of the bubbles generated by the primary device was measured by image processing [11]. 1 the apparatus consists of a cylindrical, transparent shell with an internal diameter of 10cm, which surrounds a motionless hub with a diameter of 3cm, adjusted in the center of the device.…”

“…In the present research, optimization of a primary cylindrical microbubble generator is described [11]. In Graduate student…”

“…Professor, corresponding Author Professor lindrical microbubble generator is described [11]. In this apparatus, water enters the device via six diagonal nozzles and mixes with air coming from small holes at the bottom of the device.…”

An experimental study on the effect of air bubble injection on the flow induced rotational hub

“…Rotational behavior of central hub was obtained to find operation of device in various void fractions for favorable designed regimes. In this device micro bubbles with the size of smaller than 300 lm was generated [23]. The variation of skin friction by bubbles injection in various void fractions was investigated on the rotational hub of a flow induced rotary device and rotational velocity of the hub was considered as an effective parameter related straightly to skin friction and changes in flow field.…”