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A master's thesis from Aalborg University
Book cover


Applications of the Acoustophoretic Force - Development of Acoustic Tweezing Aided Flotation

Term

4. term

Publication year

2024

Submitted on

Pages

80

Abstract

This thesis acts as an exploration of the opportunities found when applying the acoustophoretic force in an Acoustic Tweezing Aided Flotation (ATAF) system. A novel dynamic 1D acoustophoretic force expression is derived and validated for a simple geometry. This expression is used to characterize the unknown disturbing forces an air bubble would experience during ATAF with direct implementation in an Extended Kalman Filter(EKF). The EKF provided the ability to characterize disturbing forces on a modelled air bubble, but experimentally, could only characterize disturbance forces on bubbles close to the initialization position due to modelling uncertainties. The acoustophoretic force expression is also used to design a linear control strategy to cause air bubbles to interact with plastic particles. Experimentally, the ATAF system was able to align the x and y positions of the plastic particles and air bubbles with a single transducer using a PI controller and the natural buoyancy of the air bubbles respectively. The z axis position was not able to be controlled for in the experimental setup and this made air bubble and plastic particle absolute position alignment rare. Coupling between air bubbles and plastic particles was proven difficult, due to the use of olive oil, lending no hydrophobic attractive force to the interaction. This thesis concludes that there is a potential for the inclusion of the acoustophoretic force in flotation plants, though further research is required.