Entropy 2005, 7[3], 172-187
Entropy
ISSN 1099-4300
http://www.mdpi.org/entropy/

Exergy Analysis and Second Law Efficiency of a Regenerative Brayton Cycle with Isothermal Heat Addition

Naser M. Jubeh

Al-Balqa' Applied University-Faculty of Engineering Technology-Department of Mechanical Engineering Amman-Jordan, P. O. Box 15008.
Tel.: +962-06-4895174; Fax: +962-06-4894292; mob. +962 777 955 848
E-mail: jubeh@wanadoo.jo

Received: 6 June 2005 / Accepted: 3 July 2005 / Published: 5 July 2005

Abstract: The effect of two heat additions, rather than one, in a gas turbine engine is analyzed from the second law of thermodynamics point of view. A regenerative Brayton cycle model is used for this study, and compared with other models of Brayton cycle. All fluid friction losses in the compressor and turbine are quantified by an isentropic efficiency term. The effect of pressure ratio, turbine inlet temperature, ambient temperature, altitude, and altitude with variable ambient temperature on irreversibility "exergy destroyed" and second law efficiency was investigated and compared for all models. The results are given graphically with the appropriate discussion and conclusion.

Keywords: modified Brayton cycle; exergy analysis; isothermal heat addition; second law efficiency.


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