Theoretical Bases

Lepoint, T.; Lepoint-Mullie, Françoise

doi:10.1007/978-1-4899-1910-6_1

Cited by 15 publications

(10 citation statements)

References 132 publications

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“…A good agreement between the intensity distribution calculated by the FEMLAB program and by integration [5,26] has been found even in the case of low λ/r ratio (which corresponds to a high frequency ultrasound and/or large source size), i.e. in the case when there is a complicated space-dependence.…”

Section: Test Of Simulationmentioning

confidence: 77%

Optimisation of 20 kHz sonoreactor geometry on the basis of numerical simulation of local ultrasonic intensity and qualitative comparison with experimental results

Klíma

Frías-Ferrer

González-Garcı́a

et al. 2007

Ultrasonics Sonochemistry

130

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The intensity distribution of the ultrasonic energy is, after the frequency, the most significant parameter to characterize ultrasonic fields in any sonochemical experiment.Whereas in the case of low intensity ultrasound the measurement of intensity and its distribution is well solved, in the case of high intensity (when cavitation takes place) the measurement is much more complicated. That is why the predicting the acoustic pressure distribution within the cell is desirable.A numerical solution of the wave equation gave the distribution of intensity within the cell. The calculations together with experimental verification have shown that the whole reactor behaves like a resonator and the energy distribution depends strongly on its shape.The agreement between computational simulations and experiments allowed optimisation of the shape of the sonochemical reactor. The optimal geometry resulted in a 2 strong increase in intensity along a large part of the cell. The advantages of such optimised geometry are (i) the ultrasonic power necessary for obtaining cavitation is low, (ii) low power delivered to the system results in only weak heating; consequently no cooling is necessary and (iii) the "active volume" is large, i.e. the fraction of the reactor volume with high intensity is large and is not limited to a vicinity close to the horn tip.

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Section: Test Of Simulationmentioning

confidence: 77%

Optimisation of 20 kHz sonoreactor geometry on the basis of numerical simulation of local ultrasonic intensity and qualitative comparison with experimental results

Klíma

Frías-Ferrer

González-Garcı́a

et al. 2007

Ultrasonics Sonochemistry

130

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“…Other proportions used for example for activation of reactants and bulk mixing are not taken into account by calorimetry. Still it is common practice to carry out calorimetric measurements in order to characterize sonochemical reactors [1] , [2] , [3] . Further the calorimetrically determined power will be different in other liquids, since the measurement is affected by vapor pressure and viscosity of the liquid [3] .…”

Section: Additional Information and Discussionmentioning

confidence: 99%

Disequilibrium calorimetry for determination of ultrasonic power in sonochemistry

2017

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“…Enhanced sound attenuation can also lead to other secondary effects that include local heating and streaming. Both radiation pressure and streaming are prominent phenomena associated with the propagation of ultrasonic waves [23,24]. These subjects require a significant mathematical background, which may be tedious and/or mislead the readership of this article.…”

Section: Cavitation and Secondary Mechanical Effectsmentioning

confidence: 99%

“…The flow usually moves axially away from the transducer with recirculation vortices that bring fluid back to the transducer face. Visualization of streaming in liquids can easily be accomplished using thymol blue indicator [23][24][25]. The maximum axial streaming velocity (vmax) for a focused beam of intensity I and radius r, can be approximately estimated as:…”

Section: Cavitation and Secondary Mechanical Effectsmentioning

confidence: 99%

“…Obviously, a bubble cannot grow indefinitely. During expansion, bubbles reach a critical size and then collapse violently because of the inertial forces of the spherically converging liquid [23,24]. This transient (or inertial) cavitation triggers well-established mechanical (shocks) and potential chemical effects (highly excited species formation or light emission = sonoluminescence).…”

Section: Cavitation and Secondary Mechanical Effectsmentioning

confidence: 99%

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