Experimental investigation of thrust augmentation of a turbojet engine at zero ram by means of tail-pipe burning Page: 2 of 37
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NACA RM No. E6J21 * 1176 0 1 5 0327
NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS
EXPERIMENiAL INVESTIGATION OF TEXUST AUGENTATION OF A TURBOJET
ENGINE AT ZERO RAM BY MEANS OF TAIL-PIPE BURNING
By Bruce T. Lundin, Harry W. Dowman, and David S. Gabriel
The performance of a turbojet engine equipped with a tail-pipe
burner designed by the NAOA has been investigated at zero ram over a
range of rotor speeds and tail-pipe-burner fuel flows. The burner is
simple in construction, consisting essentially of an enlarged tail
pipe incorporating fuel-spray nozzles and a flame holder. An
adjustable-area exhaust nozzle is installed at the burner discharge.
A thrust augmentation of 40 percent was obtained at zero ram for
a tail-pipe-burner fuel-air ratio of 0.043 or a total fuel-air ratio
of 0.056. The over-all srecific fuel consumption for this thrust
increase was about 3.1 pounds per hour per pound of thrust. These
tests were conducted with turbine-discharge pressures lower than normal
and therefore slightly higher thrust augmentations would be expected
under rated engine operating conditions. Calculations of engine and
burner performance at ram conditions, based on the test data, indicate
a net-thrust augmentation of 140 percent at a flight speed of 900 miles
Although the maximum tail-pipe-burner discharge temperatures were
estimated at'about 40000 R, the temperature of the burner shell and
adjustable nozzle did not exceed 12000 F for any test. This condition
obviated the need for any special cooling of the burner shell.
The loss in thrust without afterburning caused by the internal
drag of the tail-pipe burner was 6.7 percent for a test condition with
oversized exhaust-nozzle area and therefore lower than rated turbine-
discharge pressure and temperature. Calculations show that this value
would be reduced to about 3 percent at rated engine conditions.
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Lundin, Bruce T.; Dowman, Harry W. & Gabriel, David S. Experimental investigation of thrust augmentation of a turbojet engine at zero ram by means of tail-pipe burning, report, January 6, 1947; (digital.library.unt.edu/ark:/67531/metadc58109/m1/2/: accessed December 16, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; crediting UNT Libraries Government Documents Department.