The war on liquids: Disintegration and reaction by enhanced pulsed blasting
•Twenty-one simulations with exothermic reactions & bursting 3-phase interactive jet.•Ten measures, including droplet size, were considered for performance assessment.•Highly unsteady acoustic fields are further energized by modulated gas feeds.•Some models showed 10% reduction in droplet size;...
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Veröffentlicht in: | Chemical engineering science 2020-04, Vol.216, p.115458, Article 115458 |
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Sprache: | eng |
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Zusammenfassung: | •Twenty-one simulations with exothermic reactions & bursting 3-phase interactive jet.•Ten measures, including droplet size, were considered for performance assessment.•Highly unsteady acoustic fields are further energized by modulated gas feeds.•Some models showed 10% reduction in droplet size; others had larger droplets.•Other measures only showed marginal differences by modulation.
Under certain conditions in preferred three-stream geometries, a non-Newtonian airblast atomization flowfield violently pulses (axially and radially) by self-generating and self-sustaining interfacial instability mechanisms. The pulsing is severe enough to send acoustic waves throughout feed piping networks. The most recent work on this system instructed that exothermic chemical reactions enhance this moderate Mach number atomization. Explored herein is the potential to further enhance reaction-assisted disintegration by independently superimposing both sinusoidal and randomized mass flow fluctuations of +/− 50% of the mean onto otherwise constant gas feed streams using surrogate models. Two nozzle geometries (low versus high prefilming distance) and multiple superimposed feed frequencies (ranging from below to above the naturally dominant tone) are considered for each gas stream, making twenty-one total long-running unsteady PLIC-VOF CFD models. Droplet size, plus nine other temporal measures, were considered for assessing atomizer performance in our energy production process. Results indicate that superimposed frequencies have potential to enhance chaotic atomization in a statistically significant manner. Depending on the geometry, the largest effect was about a 10% reduction in droplet size; however, some combinations experienced a droplet size increase. Only marginal differences were seen in the nine other measures, such as injector face heat exposure. In addition to the immediate industrial benefit from modulation, dramatic changes in acoustics were produced by imposed feed perturbations at frequencies lower than the natural tone. A detailed study of start-up flow reveals new mechanisms which explain performance differences. |
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ISSN: | 0009-2509 1873-4405 |
DOI: | 10.1016/j.ces.2019.115458 |