Bubbling controlled by needle movement

Abstract

A device for "on-demand" production of bubbles is presented. The device is based on a movable needle, through which air is injected. Bubbling is controlled by a rapid needle movement, which induces the bubble detachment. Conditions for proper function of the device include the restriction on the flow rate through the needle, sufficient needle pressure drop and adequate needle acceleration. Functionality of the device is demonstrated. Bubbling from a stationary needle is also discussed and a scaling for bubble size is proposed for the case of short needles, to which a constant flow rate is imposed through tubes of a finite volume.

Measurement accuracy of a mono-fiber optical probe in a bubbly flow

“…A bubble generator was placed in the vessel bottom. The bubble generator is a device that produces bubbles of prescribed size by imposing their detachment by a rapid needle motion (Vejrazka et al, 2008). The optical probe was inserted into the vessel from the top.…”

Description of the three-phase contact line expansion

“…The scheme of the experimental apparatus is given in figure 1. Single bubbles with diameters from 0.4 to 0.7 mm were created using a bubble generator built according to Vejražka [21]. The bubble collided with a microscope slide glass placed on a prism with a horizontal plane.…”

Collision of a small bubble with a large falling particle

“…In experiments, a single bubble (0.5 to 0.8 mm in diameter) was created in a controlled manner [2] in a glass cell (height 50 cm, width 8 cm and depth 6 cm). A glass ball (14.1 mm in diameter) was fixed to a traversing device, which displaced it downward with a velocity of 5 or 10 cm/s.…”