Abstract
Single drop particle scavenging was experimentally measured for a non-evaporating drop using an ultrasonic levitation technique. This technique enabled measurements of scavenging efficiency, E, for individual drops, and allowed for control of drop axis ratio, α, drop shape oscillations, and Reynolds number, Re, independently from drop diameter. Non-evaporating drops were used which resulted in essentially zero temperature and vapor concentration difference between the drop surface and the surrounding air, virtually eliminating the possibility of confounding phoretic effects. Plots of E versus Stokes number, Stk, became independent of α when Stk was calculated using the Sauter mean diameter (as opposed to the equivolume diameter). Furthermore, E was shown to be insensitive to both Re and drop shape oscillations, suggesting that wake effects do not have a measurable impact on E. Finally, a method was developed to relate E for spherical drops, which are assumed for existing scavenging model predictions, to E for arbitrarily deformed drops, such as those occurring in rain. Of note, these are the first measurements of droplet scavenging using ultrasonic levitation.
| Language | English (US) |
|---|---|
| Pages | 1-17 |
| Number of pages | 17 |
| Journal | Journal of Aerosol Science |
| Volume | 127 |
| DOIs | |
| State | Published - Jan 1 2019 |
| Externally published | Yes |
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Keywords
- Drops
- Oscillation
- Scavenging
- Shape
- Wake
Cite this
Experimental study of drop shape and wake effects on particle scavenging for non-evaporating drops using ultrasonic levitation. / Fredericks, Steven; Saylor, J. R.
In: Journal of Aerosol Science, Vol. 127, 01.01.2019, p. 1-17.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Experimental study of drop shape and wake effects on particle scavenging for non-evaporating drops using ultrasonic levitation
AU - Fredericks, Steven
AU - Saylor, J. R.
PY - 2019/1/1
Y1 - 2019/1/1
N2 - Single drop particle scavenging was experimentally measured for a non-evaporating drop using an ultrasonic levitation technique. This technique enabled measurements of scavenging efficiency, E, for individual drops, and allowed for control of drop axis ratio, α, drop shape oscillations, and Reynolds number, Re, independently from drop diameter. Non-evaporating drops were used which resulted in essentially zero temperature and vapor concentration difference between the drop surface and the surrounding air, virtually eliminating the possibility of confounding phoretic effects. Plots of E versus Stokes number, Stk, became independent of α when Stk was calculated using the Sauter mean diameter (as opposed to the equivolume diameter). Furthermore, E was shown to be insensitive to both Re and drop shape oscillations, suggesting that wake effects do not have a measurable impact on E. Finally, a method was developed to relate E for spherical drops, which are assumed for existing scavenging model predictions, to E for arbitrarily deformed drops, such as those occurring in rain. Of note, these are the first measurements of droplet scavenging using ultrasonic levitation.
AB - Single drop particle scavenging was experimentally measured for a non-evaporating drop using an ultrasonic levitation technique. This technique enabled measurements of scavenging efficiency, E, for individual drops, and allowed for control of drop axis ratio, α, drop shape oscillations, and Reynolds number, Re, independently from drop diameter. Non-evaporating drops were used which resulted in essentially zero temperature and vapor concentration difference between the drop surface and the surrounding air, virtually eliminating the possibility of confounding phoretic effects. Plots of E versus Stokes number, Stk, became independent of α when Stk was calculated using the Sauter mean diameter (as opposed to the equivolume diameter). Furthermore, E was shown to be insensitive to both Re and drop shape oscillations, suggesting that wake effects do not have a measurable impact on E. Finally, a method was developed to relate E for spherical drops, which are assumed for existing scavenging model predictions, to E for arbitrarily deformed drops, such as those occurring in rain. Of note, these are the first measurements of droplet scavenging using ultrasonic levitation.
KW - Drops
KW - Oscillation
KW - Scavenging
KW - Shape
KW - Wake
UR - http://www.scopus.com/inward/record.url?scp=85054881795&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85054881795&partnerID=8YFLogxK
U2 - 10.1016/j.jaerosci.2018.10.001
DO - 10.1016/j.jaerosci.2018.10.001
M3 - Article
VL - 127
SP - 1
EP - 17
JO - Journal of Aerosol Science
T2 - Journal of Aerosol Science
JF - Journal of Aerosol Science
SN - 0021-8502
ER -