Fan Efficiency

[SENGUTTUVAN]

Hi
For one of the fired heaters ID fan , the licensor spec clearly says the fan blades shall be of Radial type only. One of the vendor has offered an ID fan of DWDI configuration with efficieny of 30% during normal condition and 50% for design flow conditions. Vendor has indicated that if it is Backward curved blades design you can expect an efficieny of 50% for normal flow conditions. I stress upon the vendor that he has selected a bigger fan and that is only the efficiency is very less during normal flow conditions .I would like to know , what will be the acceptable efficiency of the Radial fans . What can be the acceptable difference between the Design flow and Normal flow conditions for any type of fan.

 

[GregLocock]

Fan efficiency curves tend to be much of a muchness, but 30% at your standard operating condition sounds very low to me, in the past I've found it fairly easy to get 50%.

Cheers

Greg Locock

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

 

[quark]

Design and normal conditions are your cup of tea. What flowrate we are talking about? In any case, like Greg suggested, the efficiency is low. The BEP for DIDW BC fans can be 70 to 80%.