intercooling between stages

geeze - I felt deja vue - grade 8 science/physics class all over again - thanx for the chuckles and explanation ;o)

you made an amazing effort to educate AND have fun doin it - not many do
 
X2 on what everyone said.

Charles always gives great in depth explnations.

Thanks for taking the time Charles.
 
Been wanting to do this for many years just never did. Turbo engineer at work asked me why I wasnt cooling between stages as soon as he saw the twins... I dunno I said, he went on with a bunch of over my head math and what not and end the end It sounded good to me... LOL
 
Now lets talk fluid dynamics / mass velocities of that volume moving thru the induction system yeaaaaaa! Using the exact opposite theory, I built a thermal expansion header thingy that converted a hot dense exaust gas into a slightly cooler much larger gas (Steam) volume to drive an APU. worked great on my turbine, wish i had a large diesel to try it on!!!
 
VERY COOL CHARLES!! Thanks for taking that time to explain that to people. Thats the good in comp d
 
Has anyone gotten any data from before/after the additional intercooler b/t stages as far as delta-T's on each side of the post-secondary cooler, pre and post secondary charger, and pressure differentials across each intercooler?

I am curious to learn how the temperature differential across the main intercooler changes with the addition of an inter-stage cooler.
 
Hurley said:
Has anyone gotten any data from before/after the additional intercooler b/t stages as far as delta-T's on each side of the post-secondary cooler, pre and post secondary charger, and pressure differentials across each intercooler?

I am curious to learn how the temperature differential across the main intercooler changes with the addition of an inter-stage cooler.
Click to expand...

To state the obvious, it should be less across the post-secondary if there is a post-primary.

There really is no way to speculate on the intake temperature (post secondary) which is actually one of the reasons I started this thread...to see if anyone had any information on it.

To me its a toss up. Run one big intercooler after the secondary and have enough water/ice to keep the intake temps down for about 13 seconds or run two smaller ones. I think running two would be cost prohibitive unless you are locked in to running a small secondary charger where it seems it would benefit the most.
 
Cost, weight & maintenance issues aside - interstage cooling is clearly beneficial.

Rule of thumb - figure 350*F max compressor discharge temp from a single (primary or atmosphere charger in compounds) and 500*F max from secondary turbo discharge...

Question: would you rather feed the top charger with 350*F or 75*F air?
Answer: obviously, intercooling is effective.

An informed decision whether or not to use it is based on ancillary factors.
 
Freakin hilarious. Maybe Erick Brown will chime in, I think he runs an a/w between stages.
 
I wonder what the difference would be in final air density if you ran the same 2 intercoolers after both turbos rather than between one and after both. The way I am looking at it is intercoolers are designed to remove heat from the charge air and if there is a larger difference in charge temp and ambient air, more heat can be dissapated so it would be better to put the intercoolers after both turbos because that is when it is the hottest.

On the other hand you have the pressure ratio of the secondary that would push more air if it is cooler so I may be thinking so far outside the box, I'm in left field.
 
Well, that's one way to idiot proof an explanation.
 
^^bigerk, consider the packaging, the airflow necessary, and the pressure drop that would be encountered by trying to do this.... for those reasons that is why the most popular method is using the largest cooler possible, after the second stage.
 
The main benefit from interstage cooling is the ability to use smaler and faster spooling secondary and still get the same total flow through the system. On the other hand if the turbos are differently matched it might even move the secondary turbo outside its efficiency islands and hinder the overall performance. So using some calculations and compressor map reading is a good place to start when wondering what if.
 
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