Dynamics of a Sonoluminescing Bubble in Sulfuric Acid

Abstract

The spectral shape and observed sonoluminescence emission from Xe bubbles in concentrated sulfuric acid is consistent only with blackbody emission from a spherical surface that fills the bubble. The interior of the observed 7000 K blackbody must be at least 4 times hotter than the emitting surface in order that the equilibrium light-matter interaction length be smaller than the radius. Bright emission is correlated with long emission times (approximately 10 ns), sharp thresholds, unstable translational motion, and implosions that are sufficiently weak that contributions from the van der Waals hard core are small.

Entropy Generation Due to the Heat Transfer for Evolving Spherical Objects

“…The alternating pattern for the bubble motion may happen due to the entropy generation by the heat transfer through the bubble wall [24], which produces lost work: less entropy generation in one cycle having a lower maximum bubble radius and, consequent, a lower minimum bubble radius at the collapse provides more expansion work for the bubble's next cycle, while a larger amplitude motion experiencing more entropy generation provides less expansion work to the subsequent motion. The calculated minimum bubble radius for the light-emitting cycles, 4.6 µm, is close to the observed value of 3.7 µm [3].…”

“…(a) The heat flow rate and (b) the corresponding entropy generation rate for the xenon bubble of Ro = 15.0 μm at PA = 1.50 atm and fd = 37.8 kHz in a sulfuric acid solution. Figure 8a shows the bubble radius-time curve for an argon bubble of Ro = 17μm driven with an ultrasound amplitude of 1.7 atm and a frequency of 28.5 kHz [33], which mimics the observed one remarkably [3]. This is a case in which the bubble emits light for two consecutive cycles after a no-emission cycle.…”

“…For a microbubble oscillating in liquid, its behavior may be affected delicately by the entropy generation due to the heat transfer through the system boundary. In fact, various nonlinear phenomena appear for sonoluminescing gas bubbles in sulfuric acid solutions [3]. The conventional approach of polytropic approximation for the bubble behavior fails to account for the nonlinear behavior due to entropy generation because P b dV is an exact differential and its integral over a cycle of oscillation vanishes [4].…”

Plasma Quenching by Air during Single-Bubble Sonoluminescence

“…While the effects of changing P a on the bubble dynamics in water are reasonably well understood, 13 for SBSL from H 2 SO 4 , the role of bubble dynamics is less clear. 30 In addition to the chemical reactions that occur, energytransfer reactions likely play a critical role in suppressing plasma formation and the consequent bright SBSL. It is well known that there are many channels by which Ar m states are depopulated.…”

Nonlinear Bubble Behavior due to Heat Transfer

“…With uniform pressure approximation which is valid for the characteristic time scale of μs, the calculated values of the minimum velocity of the bubble wall, the peak temperature and pressure are excellent agreement with the observed ones for the sonoluminescing xenon bubble in sulfuric acid solutions (Kim et al, 2006). Furthermore, the calculated bubble radius-time curve displays alternating pattern of bubble motion which is apparently due to the heat transfer for the sonoluminescing xenon bubble, as observed in experiment (Hopkins et al, 2005). The bubble dynamics model presented in this study has also revealed that the sonoluminescence for an air bubble in water solution occurs due to the increase and subsequent decrease in the bubble wall acceleration which induces pressure non-uniformity for the gas inside the bubble during ns range near the collapse point (Kwak and Na, 1996).…”