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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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An experimental investigation of a highly loaded two-stage turbine with a downstream stator revealed that (1) at equivalent design work and speed the brake internal efficiency was 0.81 and the maximum efficiency obtained was 0.85, and (2) the downstream stator left very little energy in the form of tangential velocity in the gas and, in general, performed well with 0.78 recovery being obtained at equivalent design work and speed.
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The brake internal efficiency of the highly loaded two-stage turbine was 0.79 equivalent design work and speed. The maximum brake internal efficiency was 0.84. A radial survey revealed these major defects: (1) the first-rotor throat area was too large, and a large area of underturned flow existed near the tip;(2) considerable underturning existed at the second-stator outlet; and (3) tangential components of velocity at the turbine outlet amounted to 2.5 points in turbine efficiency.
Modifying the original turbine by closing down the first-rotor throat area and shrouding the first and second rotors resulted in an over-all increase in in efficiency of 3.5 percentage points. At equivalent design work and speed the rating and aerodynamic efficiences of the modified turbine were 0.825 and 0.846, respectively. The maximum rating and erodynamic efficiencies were 0.875 and 0.906, respectively. A radial survey indicated improved firstively. A radial survey indicated improved first and second-stage efficiencies but showed that the effective throat areas of the second stator and rotor were too large.
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Investigations were conducted in the Cleveland altitude wind tunnel to determine the performance and operational characteristics of the 19B-2, 19B-8, and 19XS-1 turbojet engines. One objective was to determine the effect of altitude, flight Mach number, and tail-pipe-nozzle area on the performance characteristics of the six-stage and ten-stage axial-flow compressors of the 19B-8 and 19XB-1 engines, respectively, The data were obtained over a range of simulated altitudes and flight Mach numbers. At each simulated flight condition the engine was run over its full operable range of speeds. Performance characteristics of the 19B-8 and 19XB-1 compressors for the range of operation obtainable in the turboJet-engine installation are presented. Compressor characteristics are presented as functions of air flow corrected to sea-level conditions, compressor Mach number, and compressor load coefficient. For the range of compressor operation investigated, changes in Reynolds number had no measurable effect on the relations among compressor Mach number, corrected air flow, compressor load coefficient, compressor pressure ratio, and compressor efficiency. The operating lines for the 19B-8 compressor lay on the low-air-flow side of the region of maximum compressor efficiency; the 19B-8 compressor operated at higher average pressure coefficients per stage and produced a lower over-all pressure ratio than did the 19XB-1 compressor.