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. 2021 Apr 2;23(4):425.
doi: 10.3390/e23040425.

Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle

Ruibo Wang  1   2 , Yanlin Ge  1   2 , Lingen Chen  1   2 , Huijun Feng  1   2 , Zhixiang Wu  1   2
Affiliations

Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle

Ruibo Wang et al. Entropy (Basel). .

Abstract

Using finite time thermodynamic theory, an irreversible steady-flow Lenoir cycle model is established, and expressions of power output and thermal efficiency for the model are derived. Through numerical calculations, with the different fixed total heat conductances (UT) of two heat exchangers, the maximum powers (Pmax), the maximum thermal efficiencies (ηmax), and the corresponding optimal heat conductance distribution ratios (uLP(opt)) and (uLη(opt)) are obtained. The effects of the internal irreversibility are analyzed. The results show that, when the heat conductances of the hot- and cold-side heat exchangers are constants, the corresponding power output and thermal efficiency are constant values. When the heat source temperature ratio (τ) and the effectivenesses of the heat exchangers increase, the corresponding power output and thermal efficiency increase. When the heat conductance distributions are the optimal values, the characteristic relationships of P-uL and η-uL are parabolic-like ones. When UT is given, with the increase in τ, the Pmax, ηmax, uLP(opt), and uLη(opt) increase. When τ is given, with the increase in UT, Pmax and ηmax increase, while uLP(opt) and uLη(opt) decrease.

Keywords: cycle power; finite time thermodynamics; heat conductance distribution; irreversible Lenoir cycle; performance optimization; thermal efficiency.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Figure 1
Figure 1
T−s diagram for the irreversible steady-flow Lenoir cycle (SFLC).
Figure 2
Figure 2
p−v diagram for the irreversible SFLC.
Figure 3
Figure 3
The power output (POW) and thermal efficiency (TEF) characteristics when the HCs of HACHEX are given.
Figure 4
Figure 4
Effect of ηE on P-η characteristics when the HCs of HACHEX are given.
Figure 5
Figure 5
Effect of UT on P-uL characteristics when τ=3.25.
Figure 6
Figure 6
Effect of UT on P-uL characteristics when τ=3.75.
Figure 7
Figure 7
Effect of UT on η-uL characteristics when τ=3.25.
Figure 8
Figure 8
Effect of UT on η-uL characteristics when τ=3.75.
Figure 9
Figure 9
Effect of ηE on P-uL characteristics.
Figure 10
Figure 10
Effect of ηE on η-uL characteristics.
See this image and copyright information in PMC

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