风扇法则(Fan Law).pdf

Technical Bulletin TBN003.0/1998 FAN LAWS It is not practicable to test the not proportioned, slightly better performance of every size of fan in a performance is generally obtained when manufacturer’s range at all speeds at projecting from a given fan size to a which it may be applied. Nor it is larger one. possible to simulate every inlet density which may be encountered. Fan laws equations :- Fortunately, by use of the Fan Laws, it is possible to predict with good accuracy ⎛ ⎞ ⎛ ⎞3 N D 2 2 ⎜ ⎟ ⎜ ⎟ the performance of a fan at other speeds Q Q x x 2 1 ⎜ ⎟ ⎜ ⎟ N D 1 1 and densities than those of the original ⎝ ⎠ ⎝ ⎠ rating test. ⎛N ⎞2 ⎛D ⎞2 ⎛d ⎞ It is important to note, however, that P P x ⎜ 2 ⎟x ⎜ 2 ⎟x ⎜ 2 ⎟ 2 1 ⎜N ⎟ ⎜D ⎟ ⎜d ⎟ these Laws apply to a given point of