The Flow Of Gases In Furnaces

88

RATIONAL CONSTRUCTION OF FURNACES

if

still. in operation, and which infringe the most simple natural
laws, that is to say, a veritable collection of the monstrosities of
furnace design.

The Subdivision of a Current of Hot Gas. — Assume that the
current of hot flowing gas Q, which is giving off heat or cooling,
is to be divided between two vertical ascending channels, gi and #2,
this division to be effected in the manner shown in Fig. 45. The
veins of gas q\ and q% are at temperatures ti and fe and gi = <?2
and £i = fe. Assume that during the operation of this system the
amount of heat lost from the branch q\ is a little greater than the
amount of heat lost from the branch q% and that, accordingly,
the temperature ti becomes slightly less than fe- When fe> ti, the

FIG. 46.
weight of the column of gas q\ becomes greater than that of the
column of gas #2, and accordingly the velocity of the current qi
will become less than that of the current #2- The decrease of the
velocity of the current of gas qi results in a further lowering of
its temperature t\; in other words, the velocity of the current of
gas qi will continue to diminish, and its temperature t\ will con-
tinue to decrease. During this time the velocity of the current
of gas #2 will, on the contrary, be increased, and its temperature
will become higher. The current of gas q\ will finally cease to
flow and the entire volume of the current of gas Q will then pass
through the branch q%. But there will still be a loss of heat from
the channel qi and after the velocity of this current has decreased
to zero it will reverse and travel in the opposite direction, as is