Engine cooling Fan ... Blowing or Sucking
Engine cooling Fan ... Blowing or Sucking
(OP)
Hi,
I have a small Heat bench that I put together to test a few small M/C Radiators, at the moment its set up to suck air through the Radiator. I'm measuring the Depression with a water manometer between the Fan and the Rad for each test... e.g. lets say its 20mm H2O @ 8m/sec
Now if I change the setup so the fan is Blowing with the same given positive pressure @ 20mm will the velocity and Air Flow be the same or slightly different ?
any thoughts...
Regards
not2fast
I have a small Heat bench that I put together to test a few small M/C Radiators, at the moment its set up to suck air through the Radiator. I'm measuring the Depression with a water manometer between the Fan and the Rad for each test... e.g. lets say its 20mm H2O @ 8m/sec
Now if I change the setup so the fan is Blowing with the same given positive pressure @ 20mm will the velocity and Air Flow be the same or slightly different ?
any thoughts...
Regards
not2fast





RE: Engine cooling Fan ... Blowing or Sucking
RE: Engine cooling Fan ... Blowing or Sucking
In my limited use of electric fans for both primary and secondary installations, street and race, "suck" has always proven superior.
Rod
RE: Engine cooling Fan ... Blowing or Sucking
RE: Engine cooling Fan ... Blowing or Sucking
not2fast
RE: Engine cooling Fan ... Blowing or Sucking
I've built a Box thats around 300mm Sq, opposite the Rad is the Fan approx 300mm from the Rad.
RE: Engine cooling Fan ... Blowing or Sucking
RE: Engine cooling Fan ... Blowing or Sucking
It's rare to see someone try to push air through a radiator.
When you push air, it tend to find every other way out of the setup, exept through the radiator.
When you "suck" air, you actually ask mother nature to help you push air into the radiator. Atmosferic pressure distribution on the radiator surface is even, there is no way around the problem, air has to go through the radiator.
cheers, Chr
RE: Engine cooling Fan ... Blowing or Sucking
Good old Mother nature, that makes sense well said.
I'll explain this setup ... the actual intended application is using a Centrifugal Plastic Fan this is ducted (Blowing) towards the Radiator, I hear what your saying about the leaks and the Fan Housing (Shroud) and ducting will be Molded from Fiberglass in one piece.
After Molding I was intending to cut the inside Fan Housing on a Milling machine so as I can reduce leakage where ever possible and make this a nice close fit to the OD of the Fan, so all going well the leaks will be minimal if not zero.
not2fast
RE: Engine cooling Fan ... Blowing or Sucking
Good old Mother nature, that makes sense well said.
I'll explain this setup ... the actual intended application is using a Centrifugal Plastic Fan this is ducted (Blowing) towards the Radiator, I hear what your saying about the leaks and the Fan Housing (Shroud) and ducting will be Molded from Fiberglass in one piece.
After Molding I was intending to cut the inside Fan Housing on a Milling machine so as I can reduce leakage where ever possible and make this a nice close fit to the OD of the Fan, so all going well the leaks will be minimal if not zero.
not2fast
RE: Engine cooling Fan ... Blowing or Sucking
RE: Engine cooling Fan ... Blowing or Sucking
I agree with Landmark that when using a pusher fan the air tries to get out where ever it can. Many of the axial pusher fans now have a very large disc in the center to prevent the high pressure air from "leaking" around the center hub.
It is somewhat unfair to use the same fan in both push and pull configurations. A properly engineered fan will generally have been optimized for one or the other.
ISZ