16 Jul 2018

HIGH AIRFLOW OR HIGH STATIC PRESSURE, WICH USE ? (AXIAL AND CENTRIFUGAL FANS)

Hi, I have a question about  fans.

I need to use a fan for my carreer final proyect and im not sure what kind of fan use here. ( i have doubts about wich fan to use, high airflow fans or high static pressure fans).

My project consist in levitate a ball(or any aerodynamic object) by air , the ball will be in a tube and the fan will woks with out dust or big particles( clear air ).

There are fans that priorize air flow vs static pressure , and my question is wich type of fan i need to use here . ( I can use axial fans of centrifugal fans).

The goal here is move a ""heavy"" object (the ball) so wich kind of fan will use you ?

(I know that i need to aply bernuilli equation to know the force aply to the ball(and the drag equation later), but i dont know if i need high air speed/air flow or static ourtput pressure)

Thanks and kind regards.

17 Jul 2018

Calculate the terminal velocity of the ball using:

http://www.calctool.org/CALC/eng/aerospace/terminal

If this velocity is v m/min, and the area of cross section of the tube is A m2, then the flow rate for the fan has to be more than A x v m3/min for the ball to levitate. Use Darcy–Weisbach equation to calculate the pressure drop that the fan should develop.