空気分離に対するCavitationの利用について

抄録

Number density and size distribution of bubbles formed by cavitation in a rapid flow of liquid through a nozzle into a vessel under reduced pressures are studied in order to clarify the performance of, and also to obtain a sound basis for the design of, a simple deaerator in which such a cavitation is utilized. The way in which the dissolved gas in liquid is liberated by the swarm of bubbles rising in the liquid under reduced pressures, is also investigated experimentally. A simple theoretical consideration is put forward to explain the experimental results. The main conclusions obtained may be summarized as follows:
1) As the pressure in the vessel is reduced, the average size of bubbles formed by cavitation steadily increases while the number density of bubbles increases at first and then, through a maximum at the total pressure between 200 mmHg and 300 mmHg at the nozzle, decreases.
2) There are only small differences in the size and the number density of bubbles when different nozzles are used. The average size of the bubbles varies from 0.4×10^-2cm to 1.3×10^-2cm in diameter. The number density of bubbles amounts to about 5.0×10⁵/cm³ at the peak.
3) The air concentration in the liquid taken out of the vessel satisfies approximately the following relation.
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when the pressure at the nozzle (h_a+h₀) is larger than about 70mmHg, while, under lower pressures than this value, correction should be made by a factor ƒ.