All this boils down to is: How big a’ volume of glowing process char is needed for the gas flow in question.
It varies from big motors 9 – 11 liter displacement using 1 pint sized fuel,
and “grashoppers” using 40 – 100 ccm displacement motors and sugar-bit sized fuel.
The volume varies from 11% down to 4%.
A practical example in the “middle” of the scale:
A Volvo “farmer” wagon: 2,3 liter motor, WOT 3000 RPM 130km/h
uses half cigarette box sized fuel.
L = 2,3 liter
n = count of thousands RPM
3 = Together calculated all 4-cycle and mixing & filling parameters / second
(not per minute!)
L x n x 3 = 20,7 l/s
Now, the glow (process) volume needed:
At the Volvo 7% was chosen, and it turned out to be successful.
(with the 1/2 cigarette-box sized fuel)
To make it easy with the cut (trancuated) cone calculations I use one of the “calculator soupe” calculators.
Remember to chose a 60 degree slope!
To achieve ~60 degrees, the triangle cathethers would be about
ratio 4:7 (not exact ! )
Also, keisan online calculator works well, but I could not get it in Jpeg, or the other formats that are accepted on DOW for “transmission” here…