Power optimization of an irreversible Brayton heat engine

Journal Article · Sun Jun 01 04:00:00 UTC 1997 · Energy Sources

DOI:https://doi.org/10.1080/00908319708908865· OSTI ID:514679

Cheng, C Y; Chen, C K ^[1]

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1. National Cheng-Kung Univ., Tainan (Taiwan, Province of China). Dept. of Mechanical Engineering

Brayton cycles have been used extensively in gas-turbine power plants and aircraft propulsion systems. Finite-time thermodynamics is used to determine the maximum power output and the corresponding thermal efficiency for an irreversible closed-cycle Brayton heat engine. A realistic model is presented, which includes three types of irreversibilities: finite thermal conductance between the working fluid and the reservoirs, heat leaks between the reservoirs, and internal irreversibility inside the Brayton heat engine. The effects of heat leaks, hot-to-cold reservoir temperature ratios, and component efficiencies on the maximum power output and the corresponding thermal efficiency are studied. With component efficiencies less than 100%, the optimum ratio of the hot-end heat exchanger conductance to the total conductance of the two heat exchangers is found to be less than 0.5. Moreover, this ratio increases as the component efficiencies and the total conductance of the two heat exchangers are increased, and decreases as the hot-to-cold reservoir temperature ratio is increased.

• Sponsoring Organization: USDOE
• OSTI ID: 514679
• Journal Information: Energy Sources, Journal Name: Energy Sources Journal Issue: 5 Vol. 19; ISSN 0090-8312; ISSN EGYSAO
• Country of Publication: United States
• Language: English

Related Subjects

03 NATURAL GAS
20 FOSSIL-FUELED POWER PLANTS
33 ADVANCED PROPULSION SYSTEMS
AIRCRAFT
BRAYTON CYCLE
BRAYTON CYCLE POWER SYSTEMS
GAS TURBINE ENGINES
HEAT EXCHANGERS
HEAT LOSSES
MATHEMATICAL MODELS
POWER
THERMAL EFFICIENCY
THERMODYNAMICS