Cold-air performance of free power turbine designed for 112-kilowatt automotive gas-turbine engine. II. Effects of variable stator-vane-chord setting angle on turbine performance
The cold-air performance of the baseline power turbine designed for a 112-kW automotive gas-turbine engine was experimentally determined. Since this acial-flow power turbine has a variable stator for engine control and braking, performance data were taken at positive-power stator-vane-chord setting angles of 26/sup 0/, 30/sup 0/, 35/sup 0/ (design), 40/sup 0/, and 50/sup 0/ from the plane of ratation and at the nominal braking position of 107/sup 0/. The overall performance in terms of mass flow, torque, speed, and efficiency is presented. Overall diffuser performance and the results of rotor-exit radial surveys are also presented. Turbine efficiency varied significantly with stator setting angle, increasing to a maximum as the setting angle increased. For equivalent design speed and a design work factor of 1.172, the maximum total efficiency was 0.87 at the 45/sup 0/ setting angle although the total efficiency at the design setting angle of 35/sup 0/ was 0.77. At equivalent design speed and a design static pressure ratio of 1.775, mass flow ranged from 48.5 to 133.5 percent of design and torque ranged from 33 to 142 percent of design as the stator was opened from the 26/sup 0/ to the 50/sup 0/ setting angle. The turbine braking power was determined at a nominal stator setting angle of 107/sup 0/. Turbine internal flow characteristics were determined from static-pressure measurements and rotor-exit radial surveys with probes. The rotor-hub reaction was negative for all conditions tested at stator setting angles below 40/sup 0/. Although the hub stage reaction was -0.160 at the 35/sup 0/ setting angle (design), it was 0.131 at the 45/sup 0/ setting angle (maximum efficiency). Overall diffuser total-pressure-loss coefficients that included both the diffuser and the exit collector were obtained over the range of diffuser-inlet critical velocity ratios tested. The loss coefficient varied from 0.2 to 0.4 as the inlet critical velocity ratio increased from 0.1 to 0.5.
- Research Organization:
- National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
- DOE Contract Number:
- EX-76-A-31-1011
- OSTI ID:
- 6155245
- Report Number(s):
- DOE/NASA/1011-78/28; NASA-TM-78993
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
AUTOMOBILES
GAS TURBINES
MASS TRANSFER
PERFORMANCE
CONFIGURATION
DEMONSTRATION PROGRAMS
EFFICIENCY
EXPERIMENTAL DATA
FLOW RATE
GRAPHS
OPERATION
PERFORMANCE TESTING
TEST FACILITIES
TURBINE BLADES
DATA
DATA FORMS
INFORMATION
NUMERICAL DATA
TESTING
TURBINES
TURBOMACHINERY
VEHICLES
330103* - Internal Combustion Engines- Turbine