Figure 5: Workflow diagram to obtain optimized sonication
parameters for temperature sensitive procedure using the finite element
model directly (access to COMSOL required to run provided process code).
Next, the total power requirement is calculated by multiplying the power
density used in the model with the sample volume. If a single tip is not
capable of supplying this total power (10 and 17 W from the 2 and 3 mm
QSonica tips) the sample can be divided into more than one tube or a
larger tip can be used (however, this again affects the model geometry
which takes into account total fluid and tip size). After the input
power is selected, the mixing is optimized by using the CFD calculation
by adjusting the sonicator transducer position using the geometrical and
fluid parameter in the first block. Installing baffles could enhance
mixing but is beyond the scope of this simple model.
With this workflow one can obtain a set of optimized sonication
parameters, namely transducer position, power density, pulsing and
sonication duration that will ensure better mixing and safe temperature
rise. This same workflow is applicable to other geometries such as a
sonication bath in beakers, automated sonication systems, or miniature
lab on a chip cell lysis device (making sure to change geometry of the
model and correctly specifying the sonication transducer surface).
However, this iterative process requires resources to run the finite
element model, and in the case of tip-sonication of cell extract, a set
of master data would be sufficient to interpolate most process
conditions, without need of solving the finite element equations.