Near wall interaction in spray impingement
- Univ. of Wisconsin, Madison, WI (United States)
The hydrodynamic details of droplet-droplet and droplet-liquid film interactions on solid surfaces are believed to have a significant role in spray impingement phenomena, yet details of this interaction have not been clearly identified. The interaction among the droplets during impact affects their residence time on the surface, spreading, and droplet and liquid film stability. After impact, droplet interactions affect droplet collisions, coalescence and liquid splashing. This interaction affects secondary atomization and the droplet dispersion characteristics of the impingement process. In this study, details of droplet-droplet and droplet-liquid film interactions in solid surface impingement have been visualized using high speed photography. The effects of these interactions on secondary atomization and droplet dispersion have been quantified. Parcels of accurately spaced droplets were impinged on a heated surface and the parcels were characterized by time and length scales and by their void fraction. The impingement surface temperature was varied to examine different heat transfer regimes, from saturation through nucleate boiling to film boiling. This study concludes that for the liquid films formed in the saturation regime, liquid film breakup depends on the impinging droplet(s) energy content, the level of the liquid film surface disturbance and on the liquid film thickness. In the transition and film boiling regimes three major variables affect the interaction process: parcel configuration (droplet number and spacing), Weber number and surface superheat.
- OSTI ID:
- 277860
- Report Number(s):
- CONF-960204-; ISBN 1-56091-762-8; TRN: IM9637%%275
- Resource Relation:
- Conference: International congress and exposition of the Society of Automotive Engineers (SAE), Detroit, MI (United States), 26-29 Feb 1996; Other Information: PBD: 1996; Related Information: Is Part Of Fuel spray technology and applications; PB: 211 p.
- Country of Publication:
- United States
- Language:
- English
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