Hi all,

It would be great if you could give me your opinions on this question.

I have got a fan curve only at a given number of turns, let's say for 1440RPM.

Now I would like to use the fan laws to see how my fan curve changes at different number of turns:

Volume Capacity

*q*_{1} / q_{2} = (n_{1} / n_{2}*) *

Head or Pressure

*dp*_{1} / dp_{2} = (n_{1} / n_{2})^{2}

Let us say that with 2 we indicate all the parameters at 1440RPM.

so n2=1440RPM. Let us consider a point (which I call point 2) of the fan curve, for example: dp2=727Pa and q2=34m3/s and let us say that for that point, the fan curve says that the fan efficiency is 0.74.

Now, I want to know what happens at 500RPM. I use the fan laws to have info about the point (which I call point 1) which is equivalent to point 2:

n1=500RPM and using the fan law I get q1=11.8m3/s and dp1=88Pa.

My question is: can I assume that for the point 1 (n1=500RPM, q1=11.8m3/s, dp1=88Pa), the fan efficiency is still 0.74?

Thank you very much

## Comments rated to be "almost" Good Answers:

Re: Does Fan Efficiency Vary When The Number Of Turns Varies?" by Codemaster on 12/08/2016 6:04 AM (score 1)Re: Does Fan Efficiency Vary When The Number Of Turns Varies?" by Codemaster on 12/08/2016 5:03 AM (score 1)