fan curve differences?
fan curve differences?
(OP)
Theoretically speaking a DC fan should be operating at some point on its predetermined fan curve. I was always told that a rule of thumb is to not obstruct the fan's flow half the distance of the fan's diameter. This way, the measured fan curve may still be observed in an enclosure. However, this is not always possible. What happens to the theoretical fan curve that is determined in free air, if there are now obstructions very close to the fans outlet? Is there any way to determine what happens or any general guidelines that could be used to better define the fan perfomance characterics in such a case?






RE: fan curve differences?
I agree that performance is sometimes off the curve if the obstructions are very close to the fan. I don't know a good rule of thumb for it. There are a lot of significant variables: blade shape, quantity, angle; fan speed; obstruction shape and proximity; flow paths around the obstruction, etc.
It's worth asking the same question of the fan manufacturer, they may even have test data on an arrangement similar to yours, but it's more likely you'll have to test it under your conditions if you want a good answer.
Good luck
ko (www.ecooling.biz)
RE: fan curve differences?