I was just writing a continuation to the VOLVO project,
and everything just wanished!
Back to fundamentals:
Originally people were talking about:
UPPER hearth and
Later on, only hearth and (+) reductionzone.
So hearth today means original upper hearth.
With other words, with today’s vocabulary:
From the nozzle-tip-plane to the restriction-hole-area
is calculated as the hearth volume. A cut cone (frustum)
(Internet has special calculators for that) Easy to use.
Correspondingly, the reduction zone (area) goes (when all
from the restriction down (and in some cases up again) to the grate.
That’s the general picture…calculated for max WOT and rpm power.
For the VOLVO gas consumption
L x n x 3 = 2,4 x 3 x 3 = 21,6 liter/second was determined, that
Cigarette pak/2 was suitable. It turned out to be successful in road trafic; 130km/h regularly.
On experiance the hearth volume varies with motor (gas consumtion) size.
From 4% in “grasshoppers” (lawn movers) up to 10—12%
for 10—12 liter motors.
On this Volvo 7% hearth volume turned out to be OK.
Hearth volume = 7% of 21,6 liter/second gas production.
= 1,512 liter hearth volume.
Drawing the slope of the “upper” gasification hearth on checkered paper
(the moving/stationary part of the char),
you come practically right, if going 4 squares horizontally and 7 squares vertically.