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.