Polytechnic University of Valencia Congress, ILASS2017 - 28th European Conference on Liquid Atomization and Spray Systems

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Flexible Piezoelectric Drop-On-Demand Droplet Generation
Norbert Riefler, Thomas Wriedt, Udo Fritsching

Last modified: 18-07-2017


The size of droplets generated by piezoelectric drop-on-demand (DOD) droplet generators can be varied to a cer-tain degree within one order of magnitude. This variation means that the droplet size is not solely determined by the nozzle diameter, and the droplet generation process is not restricted to drops extruded through a nozzle in conven- tional operation. By varying the electronic driving pulse, different droplet sizes can be obtained. To investigate the interaction of piezoelectric pulse excitation and the finally produced droplets, different approaches are applied. A comparison of a modal analysis of a pure piezo based on mechanical admittance calculations proofs the usability of electrical impedance measurements. This kind of measurements are then compared to finite-element simulations of a coupled piezo system – one as actuator, the other as pressure sensor – to extend the usable methods with the result that the fluid is of minor influence on the modal frequencies. Last, two phase fluid flow simulations with consequent pressure wave evaluations of the fluid show different pressure wave frequency specta than the modalanalysis.

DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4846

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