How Can Air Throw Distance for Fans Be Calculated?

[hosaf]

Hello Everybody.

I have a problem.

I study calculate air throw distance for FANs. How can I calculate it?

So I have some data below.

Fan Diameter
Volumetric flow rate (m^3/h)
Temperature
RPM
Power

Please send me note or documents If you have any.

Thanks for your help.

 

[hosaf]

My idea about that;

0=ma-cv^2. But I am not sure it.

m:mass air rate
a:acceleration
c:constant
v:velocity

you can find cv^2 in http://www.sciforums.com/showthread.php?t=58458

 

[256bits]

I did some internet search and found only this.
Note that they say the formula is applicable for only "their" fans.

http://www.hartzellfan.com/getbulletin/series-22t/

Maybe Ashrae has some info for HVAC systems regarding a single fan.

 

[hosaf]

Thanks for your intertest.

As you motioned that formula given by Hartzellan Co. for only their Fans.

I try to calculate with Newtons First Laws (Motion in One Dimension or Two Dimension).

But I need coefficient of friction between air and air.

 

[sardar]

Hello,

Calculating air resistance can be a complex process and requires knowledge of various factors such as air density, velocity, and surface area. Based on the data you have provided, here are some steps you can take to calculate air throw distance for fans:

1. Determine the air velocity: Air velocity is a key factor in calculating air resistance. You can use the formula V = Q/A, where V is the velocity, Q is the volumetric flow rate, and A is the surface area of the fan. This will give you the average air velocity at the fan outlet.

2. Find the Reynolds number: The Reynolds number is a dimensionless parameter that helps determine the type of flow (laminar or turbulent). It can be calculated using the formula Re = (ρVd)/μ, where ρ is the air density, V is the air velocity, d is the fan diameter, and μ is the air viscosity.

3. Calculate the drag force: The drag force is the force that opposes the motion of the fan and is directly related to air resistance. It can be calculated using the formula Fd = 0.5ρAV^2CD, where ρ is the air density, A is the surface area of the fan, V is the air velocity, and CD is the drag coefficient.

4. Determine the power input: The power input is the amount of energy required to overcome the drag force and maintain a constant air velocity. It can be calculated using the formula P = FdV, where P is the power input, Fd is the drag force, and V is the air velocity.

5. Use the power input to calculate air throw distance: The air throw distance can be calculated using the formula d = (P/ρV^2) * (1 + (2/3)*(CD/ρd)), where P is the power input, ρ is the air density, V is the air velocity, CD is the drag coefficient, and d is the fan diameter.

I hope this helps in your calculations. It's always important to double-check your calculations and use accurate and precise data. Best of luck with your research!