High-power baseline and motoring test results for the GPU-3 Stirling engine

Technical Report · Mon Jun 01 00:00:00 EDT 1981

OSTI ID:6321358

Thieme, L G

In support of the Department of Energy's Stirling Engine Highway Vehicle Systems program, the NASA Lewis Research Center has installed a 7.5-kilowatt (10-hp) GPU-3 Stirling engine with a motoring dynamometer to continue to obtain data for validating Stirling-cycle computer simulations and to prepare for future component testing. The engine was originally built by General Motors Research Laboratories for the US Army in 1965 as part of a 3-kilowatt engine-generator set. Baseline tests were run to map the engine over a range of mean compression-space pressures of 2.8 to 6.9 megapascals (400 to 1000 psi) and engine speeds of 1500 to 3500 rpm with both helium and hydrogen as the working fluid. All tests were run at a heater-tube gas temperature of 677/sup 0/C (1250/sup 0/F). Maximum power obtained with hydrogen was 6.82 kilowatts (9.14 hp) at 6.9 megapascals (1000 psi) and 3500 rpm. The maximum power with helium was 4.26 kilowatts (5.71 hp) at 6.9 megapascals (1000 psi) and 2500 rpm. The highest brake thermal efficiencies obtained were 26.4 percent for hydrogen and 21.3 percent for helium. These both occurred at 6.9-megapascal (1000-psi) mean compression-space pressure and 1500-rpm engine speed. The engine output was low at high speeds as compared with that for the previously reported low-power baseline tests that used the alternator and resistance load bank instead of the dynamometer. It is felt that this reduced power was caused by degradation of heat exchanger effectiveness as a result of contamination by rust and oil. However, efficiency was higher than in the previous tests because of the installation of a noncontaminated preheater that reduced combustion system losses.

• Research Organization: National Aeronautics and Space Administration, Cleveland, OH (USA). Lewis Research Center
• DOE Contract Number: AI01-77CS51040
• OSTI ID: 6321358
• Report Number(s): DOE/NASA/51040-31; NASA-TM-82646; ON: DE81030834
• Country of Publication: United States
• Language: English

Related Subjects

33 ADVANCED PROPULSION SYSTEMS
STIRLING ENGINES
PERFORMANCE TESTING
VEHICLES
AIR HEATERS
DYNAMOMETERS
ENERGY BALANCE
ENERGY LOSSES
HELIUM
HYDROGEN
POWER RANGE 1-10 KW
THERMAL EFFICIENCY
WORKING FLUIDS
EFFICIENCY
ELEMENTS
ENGINES
FLUIDS
GASES
HEAT ENGINES
HEATERS
LOSSES
MEASURING INSTRUMENTS
NONMETALS
RARE GASES
TESTING
330201* - External Combustion Engines- Stirling Cycle