Engine Air Intake Flow

[willwoll100]

Am I right in saying that when using dimensional analysis and using a 1/4 scale pipe for an air intake on a wind tunnel model that the mass flow rate will be exactly 1/4 of the full size when the air density, viscosity and velocity do not change?

Regards

Will

 

[GregLocock]

Well, given that the cross sectional area of the pipe will only be 1/16 of the full size part, does that seem reasonable? I mean, if we could get get 1/4 the airflow through 1/16 of the area, why wouldn't we use 4 of the small ones rather than one big one? Practical observation tells you that one big one is better.

By the way, this (a) sounds like homework and (b) sounds like you are wrong.





Cheers

Greg Locock

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.

 

[willwoll100]

Cheers Greg your obviously right, there's a 61.68% difference between mass flow rates.

Will

 

[StefanHamminga]

If I were you I'd make that "roughly 60%", because things like wall friction and boundary flow can make a big difference...

Stefan Hamminga
EngIT Solutions
CSWP/Mechanical designer/AI student

 

[NakedTestMonkey]

You can get 62% out of it if you line the cylinder walls with some snake oil

 

[sumech]

flow rate will b more in case of one single big pipe,
reason is very simple, less mechanical losses as in case of one pipe