Math Quiz for a Math Wiz

[seadog!]

How many gallons of air per hour are used in an engine with the following parameters?

710 cubic inch displacement x 12 cylinders = 8520 cid

800 rpm x 60 minutes = 48,000 rph

Airbox pressure = 28-32 psi (almost 2 atmospheres)

Airbox temperature 110 degrees F

Trying to convert cubic inches to cubic feet to gallons
I came up with over 3.5 million, is this even close?

[injunear]

How many gallons of air per hour are used in an engine with the following parameters?

My question is...Why GPH??

[seadog!]

Chief-
I was hoping you'd weigh in.

GPH to be able to compare with fuel GPH. As in: For every gallon of fuel burned, X gallons of air are consumed, or: we burn 150 gallons of fuel per hour and 1.75 million gallons of air.

I think a gallon of air being a gallon of air only applies after that gallon has been pressurized, a gallon of air at 2 atmospheres should be 2 gallons if allowed to expand. It would be twice as dense.

[injunear]

I'm still trying to figure why you're calculating air flow in gallons. The CID of the engine is only a partial requirement for calculating ventilation. EMDs use much more air in the scavenging process than piston displacement. The older medium speed direct reversible 2 cycle engines (Bronz) needed pressurized engine rooms for reliable starting and slow bell operations. Air change requirements have increased with electronic controls and oil mist detectors. Many variables to consider...

[CMA_Decky]

If you really want to get exact you'll have to look at the temperature of the air post supercharging. Easiest way to take that into accont is using the ideal gas law. A gallon of hot air will have less air molecules then a gallon of cold air.

http://en.wikipedia.org/wiki/Ideal_gas_law

[seadog!]

My wife still calls me that.

She said she was looking forward to some good hot sex, and would I stay at sea a little longer until she had a chance to get some.