Konverze Energie u Atomizace Typu Effervescent

Energy Conversion in Effervescent Atomization

článek ve sborníku ve WoS nebo Scopus

en

Atomization of liquids is, from energy point of view, a process of transformation of an input fluid energy in-to surface energy of produced droplets. We qualitatively describe processes during internal flow, discharge of two-phase mixture as well as spray formation with particular focus to the energy transfer in effervescent atomi-zation. Near nozzle spray visualization elucidates the liquid breakup at different operation modes. General ener-gy equation for steady homogeneous flow is used to explain the energy forms involved in the atomization pro-cess. Numerical results illustrate their values and an influence of operational conditions on relations between different energy forms. Main part of the paper is focused on the atomization efficiency. Simple method for esti-mation of the atomization efficiency of pneumatic atomizers is proposed; surface energy of created droplets, estimated using PDA data, is compared with energy required for the atomization. Atomization efficiency of effervescent atomizers is found to be in fragments of per cents for common operation pressures and gas-to-liquid-ratios (GLRs) and it is inferior by about one order to the efficiency of simple pressure and pressure-swirl atomiz-ers for comparable droplet size. The efficiency declines with both the pressure and GLR with approximately logarithmic tendency.

Atomizace kapalin je z pohledu energie process transformace vstupní energie médií do povrchové energie vytvořených kapek. Kvalitativně popisujeme děje doprovázející vnitřní proudění, výtok dvoufázové směsi a tvorbu spreje se zaměřením na konverzi energie u effervescent atomizace. Dále je provedeno kvantitativní hodnocení jednotlivých energetických toků pro různé provozní režimy effervescent atomizeru.

Atomization of liquids is, from energy point of view, a process of transformation of an input fluid energy in-to surface energy of produced droplets. We qualitatively describe processes during internal flow, discharge of two-phase mixture as well as spray formation with particular focus to the energy transfer in effervescent atomi-zation. Near nozzle spray visualization elucidates the liquid breakup at different operation modes. General ener-gy equation for steady homogeneous flow is used to explain the energy forms involved in the atomization pro-cess. Numerical results illustrate their values and an influence of operational conditions on relations between different energy forms. Main part of the paper is focused on the atomization efficiency. Simple method for esti-mation of the atomization efficiency of pneumatic atomizers is proposed; surface energy of created droplets, estimated using PDA data, is compared with energy required for the atomization. Atomization efficiency of effervescent atomizers is found to be in fragments of per cents for common operation pressures and gas-to-liquid-ratios (GLRs) and it is inferior by about one order to the efficiency of simple pressure and pressure-swirl atomiz-ers for comparable droplet size. The efficiency declines with both the pressure and GLR with approximately logarithmic tendency.

Atomizace kapalin, transformace energie, vnitřní proudění, konverze energie, effervescent atomizace.

Energy Conversion, Effervescent Atomization, PDA, liquid break-up

2012

02.09.2012

Heidelberg University

Heidelberg, Germany

978-88-903712-1-9

proceedings of 12th International Conference on Liquid Atomization and Spray Systems

1–8

8