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Entropy 2012, 14(1), 58-73; doi:10.3390/e14010058
Article

Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle

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Received: 13 October 2011; in revised form: 18 November 2011 / Accepted: 3 January 2012 / Published: 10 January 2012
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Abstract: A thermodynamic model of an open combined regenerative Brayton and inverse Brayton cycles with regeneration before the inverse cycle is established in this paper by using thermodynamic optimization theory. The flow processes of the working fluid with the pressure drops and the size constraint of the real power plant are modeled. There are 13 flow resistances encountered by the working fluid stream for the cycle model. Four of these, the friction through the blades and vanes of the compressors and the turbines, are related to the isentropic efficiencies. The remaining nine flow resistances are always present because of the changes in flow cross-section at the compressor inlet of the top cycle, regenerator inlet and outlet, combustion chamber inlet and outlet, turbine outlet of the top cycle, turbine outlet of the bottom cycle, heat exchanger inlet, and compressor inlet of the bottom cycle. These resistances associated with the flow through various cross-sectional areas are derived as functions of the compressor inlet relative pressure drop of the top cycle, and control the air flow rate, the net power output and the thermal efficiency. The analytical formulae about the power output, efficiency and other coefficients are derived with 13 pressure drop losses. It is found that the combined cycle with regenerator can reach higher thermal efficiency but smaller power output than those of the base combined cycle at small compressor inlet relative pressure drop of the top cycle.
Keywords: regenerative Brayton cycle; inverse Brayton cycle; combined cycle; power output; thermal efficiency; thermodynamic optimization theory regenerative Brayton cycle; inverse Brayton cycle; combined cycle; power output; thermal efficiency; thermodynamic optimization theory
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

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MDPI and ACS Style

Chen, L.; Zhang, Z.; Sun, F. Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle. Entropy 2012, 14, 58-73.

AMA Style

Chen L, Zhang Z, Sun F. Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle. Entropy. 2012; 14(1):58-73.

Chicago/Turabian Style

Chen, Lingen; Zhang, Zelong; Sun, Fengrui. 2012. "Thermodynamic Modeling for Open Combined Regenerative Brayton and Inverse Brayton Cycles with Regeneration before the Inverse Cycle." Entropy 14, no. 1: 58-73.


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