What is the theoretical limit that a fan blowing air out of an enclosed space can drop the air pressure inside the space to? (Can use layman’s terms)

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What is the theoretical limit that a fan blowing air out of an enclosed space can drop the air pressure inside the space to? (Can use layman’s terms)

In: Physics

7 Answers

Anonymous 0 Comments

When the vacuum in the enclosed space is “stronger” than the fan power. (Or, the low pressure created overwhelms the blower).

Anonymous 0 Comments

Too many unknowns. Main issue is the fan design (blade type, blower versus fan versus pump, cfm relative differential pressure, etc). Is the room sealed?

Anonymous 0 Comments

Define fan, turbo pumps can take an enclosed space down to about 10^-13 of an atmosphere.

Anonymous 0 Comments

In theory, the pressure could be dropped to zero.

In reality, the question is un-answerable without a lot more variables defined.

Anonymous 0 Comments

You’re going to run into engineering limits long before you run into theoretical ones. A fan’s spin is limited by the strength of the material making up its blades, and the very strongest materials available (if they’re at a roughly human-sized scale) cap out at around 100,000 rpm. Which turns out to be a good thing, because [those centrifuges are one of the major bottlenecks for enriching weapons-grade uranium](https://en.wikipedia.org/wiki/Zippe-type_centrifuge).

Anonymous 0 Comments

In theory, a specially designed vacuum pump could pump out all of the air, and drop to 0 psia (standard air pressure is 14.7 psia). But it requires being able to move molecules without letting any air back in.

But a fan isn’t going to be able to do that. Fans can vary their performance immensely with size, power, and design, so you won’t get a good answer. You also won’t get a good answer because houses aren’t airtight, so air would always be coming into that space. However, most fans you’d be able to buy would have trouble dropping the pressure of a completely sealed chamber by 1 psi, as fans aren’t good at creating very large air pressure differences.

Anonymous 0 Comments

In layman’s terms, “skinwalled”. So yeah. There you go. Are you happy now?