Vertical Propagation of Flame

In this case the effect of convection currents becomes increasingly pronounced. The tube in which the flame travels becomes a " chimney," and, with bottom ignition, the speed of the flame is enhanced by that of the draught. With top ignition the flame tends to burn at the mouth of the tube until all the combustible mixture has risen to the top.

Gaseous Mixture.	Maximum Flame Speeds.		Lower Limit Speeds.		Upper Limit Speeds.
	Combustible Gas. Per cent, by Volume.	Flame Speed, cm./sec.	Combustible Gas. Per cent, by Volume.	Flame Speed, cm./sec.	Combustible Gas. Per cent, by Volume.	Flame Speed, cm./sec.
H2 + air	36.40	500	6.19	10	71.3	50
CH4 + air	9.52	66.6	5.80	23.3	13.35	19.1
C2H6 + air	6.53	85.6	3.30	18.1	10.60	19.7
C3H8 + air	4.71	82.1	2.37	20.8	7.30	20.3
C4H10 + air	3.66	82.6	1.95	20.1	6.53	20.3
C5H12 + air	2.92	83.0	1.61	20.2	5.40	20.2
C2H4 + air	8.45	113.7	3.55	25.8	14.00	22.2
C2H2 + air	9.90	280.0	3.45	41.0	16.00	68.0
CH4 + H2 + air	14.93	135.3	6.03	15.0	20.80	24.3
3CH4 + H2 + air	11.35	84.9	6.09	18.0	15.50	22.6
CO + air	4.84	60.1	16.29	19.5	71.19	19.4
CH4 + CO + air	15.95	91.3	9.45	21.9	21.55	19.8
CH4 + H2 + CO + air	18.92	150.0	7.70	21.2	27.57	21.8
CO + H2 + air	45.92	315.2	9.25	18.2	71.34	44.4
3CO + H2 + air	46.90	214.0	12.00	19.2	71.42	20.8
Coal gas + air	0.9	154.1	7.2	21.5	24.3	22.0
Acetone + air	5.45	96.1	2.70	55.0	8.20	30.7