Corrected compressor air flow (turbo)

[PedroCG]

hi,

on a compressor map the X axis is corrected compressor air flow, so my question is: say that on this turbo:

http://www.turbobygarrett.com/turbobygarrett/catelog/Turbochargers/GT22/GT2252_452187_6.htm

i have 25lb/min at 260K and 80KPa going in, does this mean that on the map my X point is 18,75lb/min?

i apollogise if this is a dumb obvious question...

 

[black2003cobra]

Pedro - Garret discusses how they correct air flow here:

http://www.turbobygarrett.com/turbobygarrett/tech_center/acronyms.html

Best regards

 

[PedroCG]

thanks cobra, do you know where in the inlet, impeller inducer (small diameter), or in the inlet pipe to the turbo (big diameter), the flow is corrected? theres a big diference in pressure/temperature between the two.
the turbo is going to be restricted, so atmosfere conditions can not be used

 

[black2003cobra]

I believe they are referring to the upstream stagnation pressure (Po) and temperature (To), which is what you would measure. The effects of a restriction are then taken into account by the scaling. This is evidenced by the scaling of Po/?To, (instead of P/T), which as you know follows directly from the expression for steady-state compressible flow through a restriction. This is similar to what is done to compute the air density correction factors for power as used for dynamometer measurements, and is what makes sense to me anyway. One could always call them or send an e-mail if in doubt, however. I'm sure they'd be willing to help you.

Best regards

 

[PedroCG]

Yeah i guess they should know better than anyone, but the Po and To you mention seem correct (im still walking my first steps in compresible flow...) thanks for your help again.