4 ms·
Ok, yes. Do we know how the air resistance/air flow varies as a function of surface area? Is it almost linear? I'm wondering how important it is.
by fighterpilot 5y ago
Ok, yes. Do we know how the air resistance/air flow varies as a function of surface area? Is it almost linear? I'm wondering how important it is.
- ncmncm 5y agoFeel the air coming out, vs without a filter. The slower the air is, the fewer opportunities you get to trap each dust grain. Overall miss rate improves exponentially with airflow speed.
- aronpye 5y agoThat doesn’t make sense, the higher the flow rate the higher the energy each particle has so more chance of it making it through the filter.
- ncmncm 5y agoYou might imagine so, but that turns out not to be how it works. Each time through there is a chance the particle will be blocked. It doesn't matter how fast in went in, because the mv^2 of a dust mote is tiny at any plausible speed. What matters is that N trips through gives you (1-p)^N probability of not getting caught, which falls off very fast... in fact, exponentially. A deeper-pleated filter is the way to reduce velocity in traversal.
- sixothree 5y agoI've used both. I don't have hard numbers since they are different filters, but I replaced a 1" filter with a 4" filter and I can run my fan at a lower speed.