fan torque vs speed general relationship
fan torque vs speed general relationship
(OP)
I was under the impression that the torque-speed characteristic for fans is similar to centrifugal pumps pumps, generally torque ~ speed^2... (not exact but pretty close).
The attached excerpt from "COMPUTER ANALYSIS OF POWER SYSTEMS"
by Arrillaga and Arnold suggests that a linear relationship (torque ~ speed) is generally more appropriate for fans.
Is there any basis for that? Or are they out to lunch?
The attached excerpt from "COMPUTER ANALYSIS OF POWER SYSTEMS"
by Arrillaga and Arnold suggests that a linear relationship (torque ~ speed) is generally more appropriate for fans.
Is there any basis for that? Or are they out to lunch?
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(2B)+(2B)' ?





RE: fan torque vs speed general relationship
Similar but not identical. Here are afew references to fan and pump Afinity Laws:
ht
http://pontyak.com/fans/fanaffinitylaws.html
http://w
Walt
RE: fan torque vs speed general relationship
The middle link has:
(W1/W2) = (D1/D2)^5 (N1/N2)^3 (ρ1/ρ2)
where W1/W2 is power ratio D1/D2=1 if we're fixing the wheel diameter. IF the system operates close to atmospheric pressure with maybe 0.15 psi or less dp, then the absolute pressure varies by less than 1% and rho is for all purposes constant. I think most ventilation and cooling type fans do not fall into this category.... ok to treat density as constant. Then again power proportional to speed^3 and torque proportional to speed^2
=====================================
(2B)+(2B)' ?