UCL Discovery
UCL home » Library Services » Electronic resources » UCL Discovery

Investigation of the Effect of Ultrasound Parameters on Continuous Sonocrystallization in a Millifluidic Device

Jamshidi, R; Rossi, D; Saffari, N; Gavriilidis, A; Mazzei, L; (2016) Investigation of the Effect of Ultrasound Parameters on Continuous Sonocrystallization in a Millifluidic Device. Crystal Growth & Design , 16 (8) pp. 4607-4619. 10.1021/acs.cgd.6b00696. Green open access

[thumbnail of Article.pdf]
Preview
Text
Article.pdf - Published version

Download (4MB) | Preview

Abstract

Continuous-flow crystallization of adipic acid in a millichannel chip equipped with a piezoelectric element is presented and investigated experimentally and numerically. A single, straight channel chip (cross section: 2 mm × 5 mm, length: 76 mm) made of glass, which is ultrasonically transparent, was designed and fabricated. The piezoelectric element allows studying the effect of different ultrasound frequencies in the kHz to MHz range. Ultrasound was applied in burst mode to reduce heating; this allowed operating at higher levels of input power. To accurately control the temperature of the fluid, Peltier elements were used to cool the bottom and top surfaces of the chip. Crystallization was performed in isothermal conditions, ensuring that the temperature and in turn the supersaturation were kept uniform along the channel. The effect of ultrasound frequency and sonication time was studied. Crystal size distributions at different operating conditions were obtained by laser diffraction. The distributions were narrow, with coefficients of variation ∼0.5, while the mean sizes were small (∼30 μm) and decreased when the sonication time increased. The crystal production rate increased by increasing the sonication time; this suggests that ultrasound enhances nucleation. On the other hand, in crystal breakage experiments, no difference in the size distribution of the seed crystals entering and leaving the device was observed, and hence, in this setup, ultrasound does not cause breakage. Numerical simulations of wave propagation in aqueous solution were utilized to predict the probability of cavitation, adopting a suitable cavitation threshold. The simulations showed that high pressure amplitudes are achievable inside the channel at low frequencies. The size range of bubbles which undergo violent collapse at different pressure amplitudes and frequencies was quantified. By increasing the frequency in the simulations, it was observed that the probability of transient cavitation decreases. The theoretical prediction of negligible transient cavitation at higher frequencies, in conjunction with the absence of crystals at such frequencies, indicates a strong link between transient cavitation and sonocrystallization.

Type: Article
Title: Investigation of the Effect of Ultrasound Parameters on Continuous Sonocrystallization in a Millifluidic Device
Open access status: An open access version is available from UCL Discovery
DOI: 10.1021/acs.cgd.6b00696
Publisher version: http://dx.doi.org/10.1021/acs.cgd.6b00696
Language: English
Additional information: This is an open access article published under a Creative Commons Attribution (CC-BY) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited.
Keywords: Science & Technology, Physical Sciences, Technology, Chemistry, Multidisciplinary, Crystallography, Materials Science, Multidisciplinary, Chemistry, Materials Science, ACOUSTIC CAVITATION, ADIPIC ACID, SONOCHEMICAL REACTORS, PRIMARY NUCLEATION, BUBBLY LIQUIDS, SOUND FIELDS, CRYSTALLIZATION, FLOW, IRRADIATION, TECHNOLOGY
UCL classification: UCL
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Mechanical Engineering
URI: https://discovery.ucl.ac.uk/id/eprint/1503750
Downloads since deposit
145Downloads
Download activity - last month
Download activity - last 12 months
Downloads by country - last 12 months

Archive Staff Only

View Item View Item