Enhancement of the Conversion and Concentration of Energy in a Multibubble Cavitation Zone
N.Dezhkunov (Belarusian State University of Informatics and Radioelectronics, Minsk, Belarus); A.Francescutto, P.Ciuti (University of Trieste, Trieste, Italy)
The presentation is devoted to the search of ways for increasing the efficiency of the energy conversion and concentration by collapsing bubbles in a multibubble cavitation zone. Following methods have been studied: pulsed modulation of an acoustic field, liquid degassing and cooling, increasing of the static pressure, using different gases for liquid saturation, stimulation of the cavitation by the low frequency field pulses. Sonoluminescence (SL) intensity was measured in experiments; pulse . height histograms of SL flashes and SL spectra were recorded. It is shown that the effect of the concerted simultaneous action of the studied methods considerably exceeds a sum of the effects achieved by each of these methods individually, i. e. the superadditive summation of the effects takes place. In some cases more than 3 orders of magnitude increase of the sonoluminescence intensity as compared to continuous irradiation under normal conditions has been achieved. Number of photons per one SL flash in optimal conditions of sonification was of the same order as in single-bubble experiments and SL spectra were similar to those of single-bubble experiments. Most of the methods studied cause the increase of the cavitation thresholds and increase of the acoustic and optic transparencies of the cavitation zone.
Section : 4