Mutual effects of cavitation and electromagnetic field

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Two phenomena are investigated within this work using theoretical and experimental approach. • The frequency spectrum of cavitation bubbles degradation depending on the flow • The effect of cavitation intensity on the value of electromagnetic voltage These effects are examined in a cavitation tube made of organic glass. Glass gives the opportunity to use a high-speed camera for the observation of the growth and degradation of cavitation bubbles. The first part consists of the non-linear shape of the Rayleigh-Plesset equation and its solution for given parameters. These results are used for the analysis of the Lorentz force and the estimation of the electromagnetic stress, which is generated as a result of liquid particles motion, the magnitude and direction of magnetic induction. To study the erosive effect of the cavitation, the dependence of the frequency of the cavitation bubbles collapse on the flow through the cavitation tube was analyzed. It turned out that the sensitivity of the frequency on the flowrate is very significant and strongly decreases when reaching super-cavitation when the tube core is filled with water vapor. Another important phenomenon demonstrated by experiment is the strong dependence of electromotive stress on the cavitation intensity and the frequency spectrum of cavitation bubbles collapse. It appears that passing through the cavitation zone causes a sudden change of the electromotive stress. This allows the use of cavitation as an electricity micro source. The theoretical part focuses on the rationale of the described phenomena. The main results, however, are obtained by experimental approach. And these are: • The dependence of the collapse frequency of cavitation bubbles on the flow through the cavitation zone. The frequencies are within the order of kHz. • The dependence of the electromagnetic voltage outside and inside the cavitation zone on the cavitation intensity and the conductivity of the fluid.

electromagnetic field, cavitation, Navier-Stokes equation, Rayleigh-Plesset equation, Maxwell's equations

2015-09-09

Faculty of Technologies and Systems

Slovenia

978-961-6770-31-6

Cavitation and dynamic problems – IAHRWG 2015 – Proceedings

35–42

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