Abstract |
Investigation of Cavitation Fields by
Application of Comparative Calorimetric Method
M.Margulis, I.M.Margulis (Department of
Sonochemistry, N.N. Andreyev Acoustics Institute, Moscow, Russia)
e-mail:
margulis@akin.ru
At
cavitation regime widespread acoustics methods of acoustic power W
determination give unsatisfactory results because of ambiguity of acoustic
resistance of bubbly liquid (it ranges stochastically in 100 times!). Absence
of common and direct method for measurement of W leads to incompatibility of
data obtained by different authors. Only the comparative calorimetric method
can be used to determine W absolutely (e.g. in Watts). It is based on
continuous registration of temperature T course on time t at the action of
ultrasound and the heater. If the curves T(t) are very close, the heater power
is considered as an equivalent of the W absorbed in liquid. We have obtained
experimentally the conditions at that all irradiated W is absorbed by bubbly
liquid, and we can measure all irradiated W also. At these conditions W doesn.t
depend on geometry of a vessel and on volume of liquid if size of a vessel and
level of liquid are large enough in comparison with a size of cavitation cloud.
At these conditions dependence of rate w of typical sonochemical reaction
(formation of NO2 ions under action of ultrasound) on acoustics intensity I is
linear (decreasing of w at high I is absent). Using this method we worked out
the device APM-1 that measures total irradiated and absorbed W with accuracy
3%. The results obtained can be used at calibration of ultrasound equipment,
for scientific applications at studying of processes at cavitation regime etc.
Section
: 11