The Steam Injector
A theoretical and practical treatise on the design and operation of injectors and on the flow of fluids through and the design of nozzles.
Forfatter: V. A. B. Hughes
År: 1912
Forlag: The Technical Publishing Company Limited
Sted: London
Sider: 145
UDK: 621.176
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20
THE STEAM INJECTOR.
The value of U is therefore
= PT V, + PlVl-~..Pa-V? -
n — 1
= I —V1 - p«v’) !■
( n — 1 )
But since V” = P2 V2",
Substituting 144 p for P, we get
V = i^gx — -x 144x7?! vJ 1 - (£?) „ L (x.)
V 71—1 ( Pi J
where V = velocity of discharge in feet per second;
Pif Pi — initial and final absolute pressures in pounds per
square iuch;
v 1 = volume in cubic feet of 1 Ib. of fluid at pressure px;
h = coefficient of expansion = 1'135 for dry saturated
steam, and 1-3 apprdximately for superheated
steam.
This gives for the adiabatic expansion of dry saturated steam
v = 27» -(£■*)’"} ■ ■ ■ (^i.)
v ( xpg J
Application of Formula (xi.).—To calculate the velocity
of discharge of dry saturated steam issuing into the atmo-
sphere from a boiler under an absolute pressure of 200 Ibs.
■oer square inch,
V = 279 ( 200 x 2-26 / 1 - (— Y"' l)
v I ^200' J '
— 3066 ft. per second.