Fan Impeller Parametarization/Design

[xydas7]

Hi guys.

before I start just to say how amazing this forum is..has helped out in so many situations..keep up the good work!

To my problem now. I am attempting to design a resistance device for a cycling exercise machine that uses a fan impeller (similar looking to:

http://www.cachebeauty.com/wholsale/000062338012100.main.jpg)

for providing the main resistance. Thus torque produced by the fan is my main focus.

What would be great to do would be to have an excel spreadsheet with the various variables that affect the torque produced by the fan (no of blades, blade height, blade angle, diameter etc) and the ability to generate torque vs rpm graphs by entering various values.

My experience on fans is limited. Have been doing some background reading to gain some knowledge but many books im reading at the moment are very advanced.

Therefore, I am asking if anyone could give me some pointers, key references or even some advice on how to try and approach this problem. Any help will be much appreciated.

Thanks in advance for your time and help.

Alex

 

[rmw]

In your background study, take note of how the fan HP curves vary with different blade configurations. Some blade configurations require more HP as the fan speeds up and others taper off in HP due the way that the fan is constructed.

Obviously your application wouldn't benefit very much from a fan wheel style that was non overloading..

rmw

 

[xydas7]

yes I am obviously looking at as much resistance as possible. And probably a fan whose resistance increases with speed...from my research to date I have found that:

number of blades
width of blades
blade length
blade height
blade angles (leading edge and tip)

are the main variables to look at. But need to find some formulas/maths to connect them all together

Thanks for your advice!