Antonio Lozano

Mode transitions in an oscillating liquid sheet

Longitudinal oscillations in air-blasted or air-assisted liquid sheets have been the subject of a large number of papers in the last 30 years. Frequency and sometimes amplitude are the main parameters used to characterize these oscillations. Attending to them, and also in dependence on the surface topology (e.g., the presence of perforations or ligaments), several oscillation modes have been described. In most works, two or at most three regimes are considered. Following these previous descriptions, this experimental work has found that some submodes can also be discerned. Based on visual observations, frequency measurements, and spray angle calculations, for some liquid and air flow rates up to six modes have been observed with defined transitions among them. The different modes are analyzed and characterized, and their presence is related to the flow conditions.

Combined production of electricity and hydrogen from solar energy and its use in the wine sector

Trabajo presentado en el 23rd Iberoamerican Congress, CIARP 2018, celebrado en Madrid, del 19 al 22 de noviembre de 2018

Influence of liquid properties on ultrasonic atomization

Ultrasonic atomization is very convenient because it can generate droplets with diameters of a few microns andwith very narrow size distribution. Besides, opposite to twin fluid nozzles, in ultrasonic atomization, dropletgeneration and transport are decoupled processes. Droplets are ejected from the liquid surface with very lowvelocities, so driving them is relatively simple. Although this atomization method is now common in some specificapplications, for example in household humidifiers, there are still some details about the physics of this processthat are not completely understood. Up to date, most of the published results have been limited to experimentswith water. However, it has been demonstrated that atomization rates quickly decrease as liquid viscosityincreases. This work analyzes the characteristics of ultrasonic atomization of some alternative fluids to determineif there is any influence of other physical properties such as surface tension or vapor pressure. Experiments areperformed using a commercial piezoceramic disk with a resonance frequency of 1.65 MHz. The disk is excitedwith a sinusoidal signal with voltage amplitudes that go up to 60 V. Sprays are visually characterized analyzinginstantaneous images and high speed video sequences. Besides atomization rates are calculated by measuringthe weight loss in a fixed time. DOI: http://dx.doi.org/10.4995/ILASS2017.2017.4588