Hot spot conditions during cavitation in water
Liquids irradiated with high-intensity ultrasound undergo acoustic cavitation--the formation, growth, and implosive collapse of bubbles. The energy stored during the growth of the bubble in the rarefaction phase of the acoustic field is released when the bubble violently collapses in the compression phase of the acoustic field, as acoustic noise, shock waves, chemical reactions, and the emission of light (sonoluminescence, SL). This violent collapse is predicted to generate a hot spot of thousands of Kelvin within the bubble, but, to date, there have been only a limited number of experimental measurements of the temperature of this hot spot. Although the SL of water has been studied for more than 50 years, the effective hot spot temperature during aqueous cavitation remains unresolved. Given the importance of aqueous cavitation (sonography and bioeffects of ultrasound, sonochemical remediation of aqueous pollutants, synthetic applications of sonochemistry, etc.), the authors decided to apply previous spectroscopic analysis of SL of nonaqueous liquids to aqueous solutions doped with small amounts of hydrocarbons. The authors have collected and analyzed excited-state C{sub 2} NBSL (multi-bubble sonoluminescence, light emission from the clouds of cavitating bubbles) spectra from mixtures of organic liquids in water at 20 kHz and find an effective emission temperature of 4,300 {+-} 200 K.
- Research Organization:
- Univ. of Illinois, Urbana, IL (US)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE
- DOE Contract Number:
- FG07-96ER14730
- OSTI ID:
- 20000109
- Journal Information:
- Journal of the American Chemical Society, Vol. 121, Issue 24; Other Information: PBD: 23 Jun 1999; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
Similar Records
Cavitational hydrothermal oxidation: A new remediation process. 1998 annual progress report
The Sonophysics and Sonochemistry of Liquid Waste Quantification and Remediation