• Version
• 63 Downloads
• 1.06 MB File Size
• 1 File Count
• April 21, 2017 Create Date
• April 21, 2017 Last Updated

National Advisory Committee for Aeronautics, Research Memorandum - Altitude Wind Tunnel Investigation of Thrust Augmentation of a Turbojet Engine - IV - Performance with Tail Pipe Burning and Water Injection

Thrust augmentation of an azial-flow—type turbojet engine by
a combination of tail-pipe burning and water injection has been
investigated in. the Cleveland altitude wind tunnel. Water was
injected into the engine inlet and the engine combustion chambers.
Performance was investigated over a range of simulated flight con—
ditions and water injection rates while the engine was operated at
rated speed and the tail-pipe fuel flow was regulated. to maintain
a constant turbine—outlet temperature. A constant inlet-air tem-
perature of 520° 18 was maintaimd during water injection into the
engine inlet in order to avoid icing. A fixed-area tail-pipe noz-
zle was used.

Il‘hrust increases obtainable mth engine-inlet water injection
reached a peak at a water-air ratio of 0.055 and decreased. with
larger amounts of injection, whereas thrust increases obtainable
with combustion-chamber water injection increased as the water-air
ratio was raised throughout the range of water-air ratios inves-
tigated. For the range investigated, greater mfimum thrust
increases were available with combustion-chamber water injection
than with engine-inlet water injection. Ehrust increases obtained
from either method of water injection were accompanied by large
increases in specific liquid consumption.

Augmentation of the normal thrust of turbojet engines is of
importance in improving the flight characteristics of jet-propelled
aircraft and in increasing the effectiveness of the turbojet engine
for civilian and military applications. A general program of thrust
augmentation for turbojet engines is therefore being conducted at
the NACA Cleveland laboratory. Thrust augmentation of an axial-flow—
type turbojet engine by burning fuel in the tail pipe is discussed
in. references 1 to 3. Thrust augmentation of the same turbojet
engine by water injection at the compressor inlet is reported. in
reference 4.

The performance results of an investigation made in the Cleve-
land. altitude wind. tunnel with water injection in combination with
tail-pipe burning in the following two phases are presented herein:
(1) engine-inlet water injection with tail-pipe burning; and
(2) combustion-chamber water injection with tail-pipe burning.