Sonoluminescence radiation from different concentrations of sulfuric acid

Abstract

Sonoluminescence (SL) radiation from an argon bubble in water and in different concentrations of sulfuric acid has numerically been studied to quantify the effects of vapor pressure and viscosity of the liquid on cavitation luminescence in a liquid with controllable vapor pressure and viscosity. For the solutions containing the noble gas with low partial pressure (about 4 Torr), it is shown that there exists an optimum acid solution in which both the temperature and the intensity of SL radiation become maximum. The calculations show that the maximum SL radiation is achieved from the solution of around 65% (wt.) H2SO4, which is in agreement with available experimental results.

Sonoluminescence and dynamics of cavitation bubble populations in sulfuric acid

“…The low vapour pressure of the acids is supposed to lead to more energetic bubble collapses, but can apparently only explain part of the increase in emission [16], and measurements and calculations do not necessarily result in more extreme collapse conditions than for water bubbles [17]. On the other hand, SL flashes can last orders of magnitudes longer in acids than in water [16,33], and the equilibrium sizes of brightly emitting bubbles are partly larger [16,21,34], both contributing to an increase of the total number of photons per flash. The high viscosities of the acids seem to play a major role for the special bubble dynamics that allow for the impressive SL light output, but details remain to be shown.…”

Temperature dependency of single-bubble sonoluminescence in sulfuric acid

“…The simulation results show the SL temperature in sulfuric acid is in the range of 32 000−40 000 K (see also [22]). Of course, the fitting of the experimental SL spectrum with blackbody radiation indicates that the emission originates from an optically transparent spherical shell inside the bubble in which the temperature is about 6000−20 000 K [17,18,26,27].…”

“…However, as previously shown in Refs. [22,24], the change of number of particles for the SL bubble in water typically reaches more than 1 order of magnitude due to the large vapor pressure of water. Figure 3 shows the dependency of the main characteristics of the SL bubble in sulfuric acid on the ambient temperature variations at the time of SL emission.…”

“…1). However, in water the driving parameters of maximum radiation are obtained from the crossing point of the diffusion and the shape instability curves [22,24]. This causes two different ranges of pressure amplitudes for creating stable SL in water and sulfuric acid, leading to two opposite ambient temperature dependencies.…”

“…The model has been completely described in Refs. [22][23][24] and is not repeated here for summarizing purposes. The model also considers three major instabilities which are important for the SL bubble oscillations, i.e., shape, diffusion, and positional instabilities.…”