in the running engine.
[p073]
“Unfortunately there is a limit set to this process of increasing the steam supply, quite aside from conditions inherent in the method. This is due to the fact that a certain speed of efflux cannot be exceeded without putting the flame out. Suppose, for instance, in Fig. 12, that a gas generated from a liquid is ignited at the end of the Bunsen burner F; then if the velocity of efflux of mixed gas and air in the direction AB from the mouth of F exceeds the velocity of combustion in the direction BA, the flame will obviously be carried away from the mouth of the tube and dissipated. This state of things is actually realized at pressures exceeding about 15 lbs., depending on the degree of mixture of the combustible gases used, and therefore on apparently haphazard conditions connected with the jet, the air holes, the air supply, etc.
FIG. 12.
FIG. 13.
“If, however, the velocity of the jet at the point of efflux be checked by an obstruction like a cylinder C, Fig. 13, placed co-axially with the burner tube F, the speed of combustion will no longer be exceeded (supposing C properly chosen) and flames will then burn from high-pressure gas. In this way flames were maintained generated from alcohol gas at even 40 lbs. and above.
FIG. 14.