Name: John G. L.
Status: Educator
Age: 40s
Location: N/A
Country: N/A
Date: August 2004
Question:
With respect to the surface tension of water and droplet
size when a surfactant is added to water to create a wet water solution.
If we take water with a surface tension of approximately 73 dynes and
add a fire fighting foam surfactant to the water thus reducing the
surface tension to approximately 24 dynes (approximately 1/3 of the
original surface tension of the water)- What would the droplet size of
the solution be in comparison to the size of original water droplet?
Replies:
What water droplets? Eyedropper (slow), atomizer (small), fire
extinguisher nozzle (fast), fire-hose (massive)?
Depends on your spraying apparatus.
It may not vary too much or too consistently with surface tension.
Foamy compound implies added viscosity, too. Which is just as likely to
influence droplet size.
Making droplets from an atomizer or hose-nozzle is a dynamic sort of
thing. Time and momentum and aperture size and turbulence.
Especially aperture size.
It feels plausible that an intellectually tidy dependency on surface
tension could be arranged intentionally,
but I cannot think of that scheme offhand.
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