How much restriction or flow loss from tight 90 degree bend?

I wonder if this is more reason to innercool between stages on twins/triples. It seems that cooling once between stages would significantly cut down on bends in a compound setup
 
straight 6 roar said:
Yes the losses become exponentially greater as the velocity increases. Double the air speed, quadruple the loss. When I get back to AZ I'll look up the head loss coefficient in my book.

I'd say your friends finding of a 180* bend flowing more is an error or anomaly. He probably had the probe or port or whatever the hell he was using in a "bubble" or stall portion of the tubing.

Pressure can always be used to propagate more mass through a pipe, but gaseous fluids take lots of energy to compress. You'll also hit a Reynolds # limit where the flow in the pipe becomes so turbulent due to high velocity that pumping energy costs skyrocket. Anywho, stick with the elbow the gains from a bigger bend are negligible.
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I think we should zero in on turbulent flow. Flow in an engine is turbulent throughout.

When we think about turbulent we have to view vortex and/or eddies too. Once we see them in relation to flow through an engine we can view choked flow, different from turbulent. Now the reynolds number, if I remember right the higher the number the closer we are to choked flow (flow plateau). As well as Mach .5 something something when flow is choked as well if you view it from that way.

Straight 6, if you could elaborate on Reynolds number, please.

:pop:
 
Fahlin Racing said:
I think we should zero in on turbulent flow. Flow in an engine is turbulent throughout.

When we think about turbulent we have to view vortex and/or eddies too. Once we see them in relation to flow through an engine we can view choked flow, different from turbulent. Now the reynolds number, if I remember right the higher the number the closer we are to choked flow (flow plateau). As well as Mach .5 something something when flow is choked as well if you view it from that way.

Straight 6, if you could elaborate on Reynolds number, please.

:pop:
Click to expand...

I love Wiki!!!

[ame="http://en.wikipedia.org/wiki/Choked_flow"]Choked flow - Wikipedia, the free encyclopedia[/ame]


I think the Mach 0.5 would be in "real" piping systems.

The Wiki "throretical" discussion most likely assumes a symple system, i.e a straight pipe or single orifice, hence the Mach 1.0 limit
 
Fahlin Racing said:
I think we should zero in on turbulent flow. Flow in an engine is turbulent throughout.

When we think about turbulent we have to view vortex and/or eddies too. Once we see them in relation to flow through an engine we can view choked flow, different from turbulent. Now the reynolds number, if I remember right the higher the number the closer we are to choked flow (flow plateau). As well as Mach .5 something something when flow is choked as well if you view it from that way.

Straight 6, if you could elaborate on Reynolds number, please.

:pop:
Click to expand...

while posted to Straight 6, I would hope Re would be somewhere between 10^4, and 7 x 10^6 for our purposes (limited to a 4" pipe on the high end for "clean" carbon steel pipe)
 
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