3 ms·
IMO, absolute pressure doesn't give much of a perspective. Car tire pressure is about 1.8-2.5 Bar. Your 2000 Pa atmospheric pressure change is about 20 mBar.
by labawi 7y ago
IMO, absolute pressure doesn't give much of a perspective.
Car tire pressure is about 1.8-2.5 Bar.
Your 2000 Pa atmospheric pressure change is about 20 mBar.
Pressure in an inflated balloon is about 2 mBar (0.002 Bar).
Noctua's static pressure is 0.8 mBar. Let's call it 0.5 mBar dynamic working pressure.
Not as low as I expected. Not sure if it will have a semi-reasonable speed, but that will definitely push some air.
Another comparison, 0.5 mBar is 50 Pa = 50 N/m². That gives about 50 * 0.3 * 0.3 / 10 ~ 0.5 kg force on a 30x30 cm² surface.
Finally, as the article video and data shows, it does actually work.
[1] http://scipp.ucsc.edu/outreach/balloon/labs/InflationExp.htm http://scipp.ucsc.edu/outreach/balloon/labs/InflationExp.htm
- avian 7y agoThat balloon figure doesn’t make sense to me in relation to atmospheric pressure changes. It would mean that a tied-off balloon would randomly inflate and deflate itself depending on weather.
- labawi 7y agoIt does, slightly. Pressure change 20 mBar = 2% of absolute atmospheric pressure -> about 2% balloon volume change, with corresponding 2% internal absolute pressure change, while keeping the same low differential inside-outside pressure.