Suck or blow.

[Coanda]

I was quite pleased with my first diy attempt, so now I'm planning version 1.1.

Planning to add an extra core as well as streamlining the enclosure.

 

I haven't seen it discussed anywhere so I'm wondering is it better to suck the air through the core(s) or blow, or is there no difference?

I know the effects of a fan blowing can be felt much further than suction from the same fan.

 

 

 

 

 

 

 

 

 

[Pocster]

😙😗

[RobLe]

Sucking is likely better than blowing for this application.  Blowing is directional, and has significant turbulence - good for heat transfer admittedly, but it will vary hugely over the heat exchanger - not what you want.  Sucking gives a more even laminar flow over the whole heat exchanger.  No puns in there 🙄

[SteamyTea]

Just to add to the whole DIY theme, why not fit a venturi tunnel, small fan, large flow.

Actually, why not make the heat exchanger a spiral venturi.

[Coanda]

1 hour ago, SteamyTea said:

Just to add to the whole DIY theme, why not fit a venturi tunnel, small fan, large flow.

Actually, why not make the heat exchanger a spiral venturi.

Sorry, you're way over my head now.

[SteamyTea]

Just now, Coanda said:

Sorry, you're way over my head now.

The principle is quite simple.

To get a fixed amount of air though a restriction, in a fixed time, you have to speed the air up.

This reduces the pressure at the restriction.

What you can do is add extra air at that point.  That air gets sucked in and then dragged out.  So more air movement for the same size fan/pump.  It is what Dyson does quiet well, but he relies on the general public not realising that it was all formulised in 1738, by Daniel Bernoulli.

[Pocster]

1 hour ago, Coanda said:

Sorry, you're way over my head now.

Off topic ? ( just my mind ! )

[joe90]

10 minutes ago, Pocster said:

Off topic ? ( just my mind ! )

I was waiting fir that 🙄

[JohnMo]

1 hour ago, SteamyTea said:

The principle is quite simple.

To get a fixed amount of air though a restriction, in a fixed time, you have to speed the air up.

This reduces the pressure at the restriction.

What you can do is add extra air at that point.  That air gets sucked in and then dragged out.

In simple terms, the same principle used by a carburettor, but that case the pressure drop is used suck fuel in