<VV> Flow/Pressure/Cooling

[Mel Francis]

Perhaps what IS important to remember, is that as the stock fan increases in 
RPM, past a certain point, you are not experiencing the same percentage of 
flow increase through the heads, so what you have is an increase in pressure 
inside the upper shroud.

This increase in pressure is what causes the fan to consume more horsepower, 
as the turbulence along the tips becomes a tight 'shear' point between the 
already pressurized side and the incoming air movement through the vanes.

What might work better, and is reflected in more recent fan designs, is a 
curved, swept-back tip around the perimeter of the fan. This would allow the 
fan to 'slide' along the shear point easier and as a result, might consume 
less horsepower than the stock fan at the higher RPMs.

Mel Francis


----- Original Message ----- 
From: "Joel McGregor" <joel at joelsplace.com>
To: <virtualvairs at corvair.org>
Sent: Wednesday, May 23, 2012 7:09 PM
Subject: Re: <VV> Flow/Pressure/Cooling


> Does someone have any references for this?  IF this is true I doubt we 
> would ever get to this point in our application.  I have a hard time 
> believing that increasing the pressure could actually decrease flow.  I'm 
> not claiming that it is needed.  That's a different debate.
> Joel McGregor
> ________________________________________
> From: virtualvairs-bounces at corvair.org [virtualvairs-bounces at corvair.org] 
> On Behalf Of Smitty [vairologist at cox.net]
> Sent: Wednesday, May 23, 2012 6:59 PM
> To: virtualvairs at corvair.org
> Subject: <VV> Costom Fans/ Thrown Belts
>
> Exactly right.  Both theory of fluid dynamics and  experimental data show
> that at some point, an increased differential in  pressure through a 
> nozzle
> (cooling fins) has no increase in flow and can  actually lead to a 
> decrease
> in flow.
>