The Flow Of Gases In Furnaces

THE SUBDIVISION OF A CURRENT OF HOT GAS

91

descending channels q\ and #2 having equal temperatures t\ and fe,
that one of these streams takes up the heat a little faster than the
other and that, for example, ti becomes slightly less than fe-
The column of gas q\ becomes, therefore, slightly heavier than the
column #2, the current qi commences to flow with greater energy,
and its velocity increases; .ti commences to become sensibly less
than fe, the current q\ has a greater cooling effect than the current
g2 which continues, on the contrary, to take up more heat; and,
in the end, the entire stream of gases passes through the branch gi,
while in the branch q2 there will be established at the same time a
reverse current which circulates as indicated by the clotted arrows
(Fig. 48).

Q

S-^

vb

Q

\
tf1

\
72
I

y

1

//•

1

'/

^ x

tl

t<>
s

V

V

;^;

«"—»
*"— Q

FIG. 48.

^^;,,,. ,;,/^

FIG. 49.

Therefore, a current of cold gases which are being heated cannot
be subdivided equally between descending channels.
When the subdivision of a stream of cold gases is made through
ascending channels, the results will be as desired. Assuming that
the currents flowing as indicated in Fig. 49 were not equal, q\>q%
and, consequently, fe>£i- If fo>£i, the weight of the column
<72 will be less than the weight of the column gi, the current #2 will
become stronger; this will cause the temperature fe to become
lower; at the same time t\ will increase in this manner and the
two temperatures will be equalized; the two currents q\ and #2
will therefore be maintained equal.
• It therefore follows that when a current of cold gas is to be
heated it should be subdivided into a number of ascending streams.