A bubble generation device includes: a metallic narrow tube (10) through which water passes; and a pump that pressure-feeds the water containing a gas component into the metallic narrow tube (10). A drawer (11) in which a path through which the water passes is narrower than the front and the rear thereof in the flow direction of the water is disposed on the inside of the metallic narrow tube (10). The drawer (11) has the rectangular cross section orthogonal to the flow direction. The gas component contained in the water is dissolved in the water by pressure-feeding the water to the drawer (11), bubbles are evolved due to a decrease in pressure in the drawer (11), turbulent flow is generated in the water in the drawer (11) to crush bubbles in the water by the shearing force thereof, and bubbles are crushed by a shock wave caused by transonic flow occurring in the water that has exited from the drawer (11).

A jet injection device that incorporates nanobubbles (ultrafine bubbles) in a mist includes: a two-fluid nozzle configured from a circular nozzle outer cylinder and an air connection tube integrally and perpendicularly connected to the nozzle outer cylinder; a nanobubble generation device that supplies the nozzle outer cylinder of the two-fluid nozzle with high-pressure nanobubble water; and a compressor that supplies the air connection tube of the two-fluid nozzle with high-pressure air. The gas-injected bubble water generated from the nanobubble generation device is pressure-fed to the nozzle outer cylinder of the two-fluid nozzle, and compressed air from the compressor is pressure-fed to the air connection tube of the two-fluid nozzle. In the two-fluid nozzle, the high-pressure gas-injected bubble water and the compressed air serve as a gas-liquid fluid mixture, and are injected at a high speed in mist form from a nozzle cylinder of the two-fluid nozzle.

A microfluidic device for generating microbubbles includes a substrate and a microfluidic channel embedded in the substrate. The microfluidic channel includes a plurality of fluid inlets, at least one bubble formation outlet having a nozzle with an adjustable diameter, and a flow focusing junction in fluid communication with the plurality of fluid inlets and the bubble formation outlet. A method for mass producing monodisperse microbubbles with a microfluidic device includes supplying a flow of dispersed phase fluid into a first fluid inlet of a microfluidic channel, supplying a flow of continuous phase fluid into a second fluid inlet of the microfluidic channel, and adjusting a diameter of a nozzle to obtain a plurality of monodisperse microbubbles having a specified diameter.

The present invention provides positively or negatively charged nanobubbles, with the goal to clarify the effects of positively or negatively charged nanobubbles on microorganism and plant growth. The present invention also provides charged nanobubble dispersion liquid that contains 10.sup.5 to 10.sup.10 fine bubbles. The fine bubbles are dispersed in the liquid, are positively or negatively charged, have an average particle size of 10 nm to 500 nm, and have a zeta potential of 10 mV to 200 mV.

The purpose of the present disclosure is, in a bubble generating device provided with a bubble generating unit for generating minute bubbles in water flowing through the inside of the cylindrical main body unit, to improve the bubble generating efficiency of the bubble generating unit. Provided is a bubble generating device provided with a cylindrical main body unit and a bubble generating unit disposed within the main body, wherein: the bubble generating unit is provided with slits extending radially centered on one point within the main body unit in a cross-sectional plane of the main body unit, and a column part protruding from the inner peripheral surface of main body unit and formed on the peripheral edge of the slits; and the amount of protrusion of the column part is gradually reduced toward the upstream side from the peripheral edges of the slits, and the column part has a recessed part formed on the downstream surface.

Provided is an ultrafine bubble generation device for aquaculture or wastewater treatment with which it is possible to efficiently cause ultrafine bubbles to be dissolved or to coexist, and to increase the concentration of a gas in the liquid. An ultrafine bubble generation device for aquaculture or wastewater treatment provided with a channel for channeling a liquid, a compression device for pumping a gas into the channel, and a bubble generation medium for releasing the gas pumped by the compression device as ultrafine bubbles into the liquid in the channel, wherein the bubble generation medium is formed from a carbon-based porous material and is disposed so as to be horizontal or below horizontal with respect to the direction of flow of the liquid in the channel.

Provided is a UFB generating apparatus that can achieve compactness, power saving, and low cost. To this end, a liquid containing unit for supplying a liquid to a UFB generating head is fluidly linked to the UFB generating head at a position higher than the UFB generating head in a direction of gravitational force.

Provided is a UFB generating apparatus capable of manufacturing an ozone UFB-contained liquid with high purity and quality. To this end, in the UFB generating apparatus capable of generating UFBs containing ozone by causing film boiling in ozone water, a liquid contact portion to come into contact with the ozone water is made of a material with corrosion resistance to ozone water.

Provided is an ultrafine bubble generating method and an ultrafine bubble generating apparatus capable of efficiently generating a UFB-containing liquid with high purity. To this end, a flow passage inner volume is varied by using a flow passage inner volume varying element, the liquid is pressurized such that the liquid passes through a narrow portion at high speed and flows into a depressurizing area.

Provided is a UFB-containing liquid production apparatus that can efficiently produce a UFB-containing liquid with a UFB generation unit. The UFB-containing liquid production apparatus includes: a gas dissolution unit that produces a gas-dissolved liquid by dissolving a gas into a liquid supplied from a liquid supply unit; a UFB generation unit that generates UFBs in the flowing-in gas-dissolved liquid; and a circulation path that supplies the gas-dissolved liquid to the UFB generation unit and supplies a UFB-containing liquid produced by the UFB generation unit to the liquid supply unit. In the circulation path, there is provided a micro-bubble reduction unit that reduces an amount of micro-bubbles contained in the gas-dissolved liquid to flow into the UFB generation unit.