Essential cooling mods?

Florence_NC

Senior Member
Joined
Sep 25, 2018
Threads
2
Messages
340
Reaction score
220
Location
North Carolina
Vehicle(s)
2018 Type R
Country flag
Fair enough. I was thinking along the lines of introducing air entrainment
And to add more, entrainment is a real effect, and it does have some existence in a vehicle at motion.

A couple of places I can think of on a car where entrainment would be highest would be a place like the hood vent you talked about. If you place a hood vent near the front of the hood (basically directly behind the radiator) where the air is passing over at a high velocity, some entrainment would occur. Also as mentioned before in this thread, a drivers window rolled down 2 inches, opening into the high velocity air passing outside of the window. This would also have some entrainment effect.

But in the case of the hood, the fast air over the top of the hood near the grill creates a low pressure due to Bernoulli, while the air passing through the grill is pressurizing the volume under the hood. This creates a big pressure differential. Same thing with the window down, the air passing on the outside of the window is fast, thus causing a Bernoulli-induced drop in pressure outside the glass. While at the same time the relatively still air inside the car has a higher pressure. And the cabin air pressure can be boosted even more by the cowl vent which feeds the heat/AC system and can pressurize the cabin. In both the hood vent and window-down examples, entrainment does move some air. But the pressure differentials are a much, much bigger source of air displacement.
Sponsored

 

86salmon

It's Hedley, Hedley Lamarr!
Joined
Sep 26, 2018
Threads
31
Messages
3,186
Reaction score
5,443
Location
Chucktown, SC
Vehicle(s)
2018 Civic si sedan, 2001 Nissan Frontier
Build Thread
Link
Vehicle Showcase
1
Country flag
But I probably covered it in post #121.
Thanks for the thorough posts.

You would have to be more specific about the process before I can comment.
I had a set of specific venturi devices in mind that use the pressure differences to entrain and blend air as well as generate greater flow through a tube.
 

Florence_NC

Senior Member
Joined
Sep 25, 2018
Threads
2
Messages
340
Reaction score
220
Location
North Carolina
Vehicle(s)
2018 Type R
Country flag
I had a set of specific venturi devices in mind that use the pressure differences to entrain and blend air as well as generate greater flow through a tube.
Most such devices use both entrainment and venturi effect to produce flow and/or mixing. Entrainment uses viscosity-induced friction forces, venturi uses pressure differential. How much of each is dependent on several factors

I can give a fully detailed physics-light explanation if you really want it. But it would be a bit long and probably a couple of days before I could do it.
 


JoYu

Senior Member
Joined
Oct 8, 2017
Threads
2
Messages
125
Reaction score
75
Location
Ca
Vehicle(s)
2019 type R
Country flag
Everyone is talking about the ambient temperature under the hood, I don't think most of the cooling comes from the air around the engine. I'm sure it has a small effect, but not where I would spend my focus.
 

UFO CTR

Senior Member
Joined
Oct 12, 2016
Threads
22
Messages
2,530
Reaction score
1,877
Location
San Frrancisco, CA
Vehicle(s)
2017 CTR#1348
Country flag
Yes, mixing is a critical part of this, assuming we are talking about fluids.

Air is a mix of different molecules, each with different characteristics. When 2 nitrogens hit each other, they act differently than 2 oxygens. And a C02 hitting an argon acts way different. But taken at volumes large enough for the individual differences to be filtered out, it acts like a continuous homogeneous fluid.

If you were to inject something radically different from the jet, like maybe helium, then it gets a bit nuanced. Helium is much lighter, and has very different inter-molecular properties. But it does still mix readily with air. So initially out of the jet, it may not act purely as a continuum. But after sufficient time/distance from the jet, the mixing becomes thorough enough to now act as a continuum.

Keep in mind that a continuum can also be a solid, so mixing is not a consideration here. A set of molecules is bound into a continuous solid, and those bonds maintain (more or less) the same attachment to the same adjacent molecules. They can move in distance, stretching and compressing the bonds, but the bonds stay intact. This is clearly not mixing.

A tire is a continuum of rubber, if you press something into the tread, the molecules in contact will deflect, which deflects the ones next to it, etc, etc. Once you get sufficiently far away from the initial point of deflection all of the deflection has been damped and dissipated, molecule by molecule, until no effect is seen.

A brick is a continuum, and acts just like the rubber, only the distance of deflection is many orders of magnitude smaller.
I suspect tire / rubber band were, but didn't even think bricks are continuum. and yes, bricks shouldn't deflect too much before it shatters...brittle material, :)

EDIT: This is good stuff!!!
Sponsored

 
Last edited:


 


Top