Unsteadiness in Effervescent Sprays: a New Evaluation Method and the Influence of Operational Conditions

A new evaluation method of unsteadiness of the spray generated by an effervescent atomizer is presented. The method is based on measurements of pressure fluctuations in the atomizer mixing chamber. Measurements, made under different atomizer operational conditions, show that the spray unsteadiness depends mainly on gas-to-liquid ratio (GLR). Decrease in GLR causes the spray to become more unsteady. The relation between atomizer internal two-phase flow pattern and the spray unsteadiness is elucidated by visualization of the internal two-phase flow using a digital camera and the use of published two-phase flow maps. Findings of the new method are complemented and confronted with the results obtained by the use of the spray unsteadiness evaluation method of Edwards and Marx.
V příspěvku je odvozena nová metoda měření nestabilit spreje u trysky typu effervescent. Metoda je založena na měření tlakových pulzací ve směšovací komoře trysky. Měření na modelové trysce ukazují vliv provozních podmínek: tlaku a směšovacího poměru plynu a kapaliny. K osvětlení příčin nestabilit je využita vizualizace vnitřního dvoufázového toku pomocí vysokorychlostní kamery. Výsledky měření nestabilit pomocí uvedené metody jsou porovnány s metodou odvozenou Edwardsem and Marxem.

Keywords

Spray unsteadiness, effervescent atomizer, measurement method, two-phase flow, Nestability spreje, effervescent tryska, metoda měření, dvoufázový tok

Citation

Atomization and sprays. 2008, vol. 18, issue 1, p. 49-83.
http://www.dl.begellhouse.com/journals/6a7c7e10642258cc,7da5e43f06d335eb,4319cefd3bbc5dc2.html

Document type

Peer-reviewed

Document version

Accepted version

Language of document

en

Document licence

(C) Begell House