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National Advisory Committee for Aeronautics, Research Memorandum - Altitude Wind Tunnel Investigation of a 3000 Pound Thrust Axial Flow Turbojet Performance

An investigation has been conducted in the KACA Cleveland alti-
tude wind tunnel to determine the performance of a turbine operating
as an integral part of a turbojet engine. Turbine performance data
were obtained. while the engine was run over its full operable range
of speeds at various simulated altitudes and flight Lhch numbers and
with four nozzles of different outlet area.

An analysis of the turbine performance data showed that the
turbine was effectively utilized in the standard installation. A
maximum turbine efficiency of O. 875 was obtained with the standard
exhaust nozzle at a simulated altitude of 15,000 feet, a flight
Lhch number of O. 55, and a corrected turbine speed of 5900 rpm.

The perfornance of a turbine operating as an integral part of
a turboJet engine is of interest because it is desirable to know
the capabilities of the turbine and how effectively the turbine is
utilized in the engine. A complete turchet engine was investigated
in the NASA Cleveland altitude wind tunnel and. ananalysis of the
turbine performanpe data obtained is presented. Turbine data were
obtained over a much wider range of operating conditions than in
previous twbine investigations in the altitude wind tunnel.

The investigation was conducted at various simulated altitudes
and flight mch numbers. At each simulated flight condition, the
engine was run over its full operable range of speeds. The use of
four engine exhaust nozzles of different outlet area extended the
range of turbine operation over which performance data could be
obtained.

Turbine performance data obtained for various altitudes, flight
Inch numbers, and with different exhaust-nozzle-outlet areas are
reduced to sea-level conditions and presented in a single plot.
Curves of constant corrected turbine speed, constant turbine pres-
sure ratio, and. constant efficiency are shown therein.