How to centrifugal fan design?

[prapat]

Hello everybody, I would like to incrase pressure of primary air fan to 400 mbar. I try to use fan laws for calculate new fan dimension. In calculate horsepower of motor increase to 410 kW.
How to decrease horsepower?
Does anyone know about the parameters that affect the design of fan? For example, is there an optimum power or optimum number of blades, curvature and shape for the blade? Is there any book I could refer to?
Thanks.

 

[insult2injury]

You want to increase pressure and at the same time decrease horsepower?

I2I

 

[CanuckMiner]

prapat,

If you're looking for a book, you might consider "Fan Engineering" by Howden (formerly Buffalo Forge)

http://www.howden.com/en/Businesses/HowdenBuffalo

Cheers,
CanuckMiner

 

[prapat]

Thank you for your suggestion. I know in case of pressure of fan increase, the horsepower must increase follow the fan laws. However, I would like to know how to optimum the horsepower.
Thanks.

 

[GregLocock]

Minimum horsepower for a given volumetric flow and pressure differential is obtained using (generally) a large diameter fan with few blades, careful blade shaping and the correct pitch and speed. In practice industrial fans tend not to follow all of these crietria. The most efficient practical type of fan that you need depends on your required delivery parameters.

6 psi in the old money can be achieved by a variety of different blowers.



Cheers

Greg Locock

SIGlease see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[amorrison]

Note that Greg said "blower" - not "fan". They are an entirely different concept.

A blower can give you your 6 psi - a fan might give you only 0.25 psi (6 inches water gage) pressure.

 

[btrueblood]

...and to follow amorrison's arguement, if you simply tried to turn up the rpm of a fan to achieve more pressure, the fan blades will stall at some pressure (like 1/4 psi) well below the 0.4 bar you are trying to achieve. Fan laws and pump laws will only take you so far - typically a fan is rated at its maximum possible rpm/flow before stall occurs.