ajayguhan
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Why most of the fans have three wings, why not two, four, five and so on.
That is correct - what are the factors that the number of blades depends on?The site says that they can have any number of blades depending upon certain factor.
... are there any other factors which may influence the design of a commercial fan?It doesn't explain why most commercial fans have three blades?
Doug Huffman said:Aside from commercial design considerations, as the number of blades in an axial (compare ducted) fan increases so does their restriction of the flow rate. Gedanken; imagine an operating fan, change only the number of blades, in the limits the fan stops moving air axially.
No, just a thin plastic "grill" in an otherwise open front and back. Do a google search for "household box fan images", and you see a few similar to our 20 inch box fan. Ours is old (30+ years) and has square corners instead of rounded corners.Simon Bridge said:Hmm does the box housing all-but obscure the fan?
A three bladed fan has constant MMOI about any transverse axis. This is important in some high speed applications, particularly if the fan must yaw (such as a power generating windmill).AlephZero said:A 2-blade rotor has a different moment of inertia about different axes (along the blades and at right angles to them). That can create dynamic instability problems, but it's not likely to affect a low-speed room fan. It is a design issue for 2-blade aircraft propellers and helicopter rotors though.
Four blades are no better or worse than and other number greater than 2, so far as rotor balancing is concerned.