Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle
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 (<inline-formula><math xm...
| Main Authors: | , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-04-01
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| Series: | Entropy |
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| Online Access: | https://www.mdpi.com/1099-4300/23/4/425 |
| _version_ | 1797539068868820992 |
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| author | Ruibo Wang Yanlin Ge Lingen Chen Huijun Feng Zhixiang Wu |
| author_facet | Ruibo Wang Yanlin Ge Lingen Chen Huijun Feng Zhixiang Wu |
| author_sort | Ruibo Wang |
| collection | DOAJ |
| description | 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 (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula>) of two heat exchangers, the maximum powers (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>), the maximum thermal efficiencies (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>), and the corresponding optimal heat conductance distribution ratios (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>) and (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>) 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 (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula>) 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 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mo>-</mo><msub><mi>u</mi><mi>L</mi></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>η</mi><mo>-</mo><msub><mi>u</mi><mi>L</mi></msub></mrow></semantics></math></inline-formula> are parabolic-like ones. When <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula> is given, with the increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula>, the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> increase. When <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula> is given, with the increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula> increase, while <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> decrease. |
| first_indexed | 2024-03-10T12:41:06Z |
| format | Article |
| id | doaj.art-ee36b82378d14069a3428137595b1edb |
| institution | Directory Open Access Journal |
| issn | 1099-4300 |
| language | English |
| last_indexed | 2024-03-10T12:41:06Z |
| publishDate | 2021-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Entropy |
| spelling | doaj.art-ee36b82378d14069a3428137595b1edb2023-11-21T13:56:44ZengMDPI AGEntropy1099-43002021-04-0123442510.3390/e23040425Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir CycleRuibo Wang0Yanlin Ge1Lingen Chen2Huijun Feng3Zhixiang Wu4Institute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, ChinaInstitute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, ChinaInstitute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, ChinaInstitute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, ChinaInstitute of Thermal Science and Power Engineering, Wuhan Institute of Technology, Wuhan 430205, ChinaUsing 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 (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula>) of two heat exchangers, the maximum powers (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>), the maximum thermal efficiencies (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>), and the corresponding optimal heat conductance distribution ratios (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>) and (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>) 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 (<inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula>) 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 <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>P</mi><mo>-</mo><msub><mi>u</mi><mi>L</mi></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>η</mi><mo>-</mo><msub><mi>u</mi><mi>L</mi></msub></mrow></semantics></math></inline-formula> are parabolic-like ones. When <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula> is given, with the increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula>, the <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula>, and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> increase. When <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>τ</mi></semantics></math></inline-formula> is given, with the increase in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>U</mi><mi>T</mi></msub></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>P</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>η</mi><mrow><mi>max</mi></mrow></msub></mrow></semantics></math></inline-formula> increase, while <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>P</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msub><mi>u</mi><mrow><msub><mi>L</mi><mi>η</mi></msub><mo stretchy="false">(</mo><mi>o</mi><mi>p</mi><mi>t</mi><mo stretchy="false">)</mo></mrow></msub></mrow></semantics></math></inline-formula> decrease.https://www.mdpi.com/1099-4300/23/4/425finite time thermodynamicsirreversible Lenoir cyclecycle powerthermal efficiencyheat conductance distributionperformance optimization |
| spellingShingle | Ruibo Wang Yanlin Ge Lingen Chen Huijun Feng Zhixiang Wu Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle Entropy finite time thermodynamics irreversible Lenoir cycle cycle power thermal efficiency heat conductance distribution performance optimization |
| title | Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle |
| title_full | Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle |
| title_fullStr | Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle |
| title_full_unstemmed | Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle |
| title_short | Power and Thermal Efficiency Optimization of an Irreversible Steady-Flow Lenoir Cycle |
| title_sort | power and thermal efficiency optimization of an irreversible steady flow lenoir cycle |
| topic | finite time thermodynamics irreversible Lenoir cycle cycle power thermal efficiency heat conductance distribution performance optimization |
| url | https://www.mdpi.com/1099-4300/23/4/425 |
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