Rotary Engine Volume Flow Calculation 2

[Turbinator]

I know how to calculate the volume flow of a 4-stroke piston engine, Engine Speed x Displacement x Volumetric Efficiency / 2.

How can a similiar calculation be done for a Wankel engine? I've read the previous topics on this board and scoured Google but came with no satisfactory results.

 

[hydrae]

Neither have we

see thread

http://www.eng-tips.com/viewthread.cfm?qid=96283&page=2

Hydrae

 

[EngJW]

If you have access to an SAE handbook there is an equation for the displacement of a rotary engine. It is the displacement of one rotor chamber and you multiply this times the number of rotors to get the total. The total displacement is then multiplied by 2 to get the equivalent displacement of a reciprocating engine (since the rotary has one power stroke per revolution vs. one in two revolutions for a recip).

Perhaps you have this number already. You could then calculate air flow the same as with a recip.

Now for the qualification: I looked through my notes and could not find anything specific, but I think this method should be valid. I haven't tried it however.

 

[Turbinator]

Thank you EngJW. That seems to be the part I was missing, how the displacement of a rotary is rated.
The rotor also spins at 1/3 the output shaft speed, so

Flow= Output Shaft Speed x Rated Displacement x Volumetric Efficiency x 2/3

This seems to match well with the dyno numbers.