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Old 12-23-2011, 06:20 PM   #25 (permalink)
mort
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Quote:
Originally Posted by jakobnev View Post
W=dP * Q is woefully inaccurate for expansion ratios much greater than one tho.

Any chance you can redo that in SI-units?
Hi jakobnev,
You must be thinking of some other situation. If your p1 is atmospheric the power to pump something is the sucking force times the flow. The equation is exact.

I guess I'll leave the SI conversion for somebody else. I never got the feel of 100000 Pascals. The only numbers you need to make up are A/F (14.7:1) energy density of the fuel (about 12 kwh/kg maybe for petrol) and engine efficiency.

-mort
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