Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator
Heat rejection of a linear alternator (LA) plays a pivotal role in achieving high performance and a long lifetime. This paper proposes an innovative approach for the first time that utilizes a high emissivity coating formulated from a blend of microsilica and graphene nanosheets to enhance the radia...
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| Format: | Article |
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Elsevier
2025-04-01
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| Series: | Energy Conversion and Management: X |
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| Online Access: | http://www.sciencedirect.com/science/article/pii/S2590174525001758 |
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| author | Qingyue Jin Guoyao Yu Haojie Sun Jing Luo Hangyu Ma Yong Li Shunmin Zhu Ercang Luo |
| author_facet | Qingyue Jin Guoyao Yu Haojie Sun Jing Luo Hangyu Ma Yong Li Shunmin Zhu Ercang Luo |
| author_sort | Qingyue Jin |
| collection | DOAJ |
| description | Heat rejection of a linear alternator (LA) plays a pivotal role in achieving high performance and a long lifetime. This paper proposes an innovative approach for the first time that utilizes a high emissivity coating formulated from a blend of microsilica and graphene nanosheets to enhance the radiation heat dissipation inside the LAs, offering advantages of structural simplicity and cost-effectiveness. To elucidate the radiative heat transfer characteristics interacted with the oscillating flow within the LA, firstly, a CFD model was developed to analyse the oscillating flow coupled radiative heat transfer within a 1.5-kW LA. The effects of coating emissivity, backdrop temperature, dissipated heat by the components, and mean pressure on the heat transfer of the LA’s electromagnetic components were investigated. Numerical calculations indicate that the high emissivity coating reduces the average temperature of the coil adjacent to the permanent magnet, the permanent magnet itself, and the inner stator by approximately 10.0 K, while the temperature of the coils adjoining the outer housing and the outer stator decreases by about 4.2 K. Additionally, the efficacy of the high emissivity coating in enhancing the cooling of these components was significantly amplified under elevated heat generation conditions. Subsequently, an experimental test rig was built and the results showed that the high emissivity coating reduces the temperature of the coil and outer stator by 1.1 K and 0.2 K, respectively, increases the output electric power by 6.6 W, and improves thermal-to-electric efficiency by 0.3 % under the operating conditions with cooling water temperature of 298 K and mean pressure of 4.5 MPa. This work provides valuable perception into enhancing the internal cooling effect of LAs. |
| format | Article |
| id | doaj-art-49f2d6c501b94c2190a9c8dadcc874ca |
| institution | Kabale University |
| issn | 2590-1745 |
| language | English |
| publishDate | 2025-04-01 |
| publisher | Elsevier |
| record_format | Article |
| series | Energy Conversion and Management: X |
| spelling | doaj-art-49f2d6c501b94c2190a9c8dadcc874ca2025-08-20T03:49:41ZengElsevierEnergy Conversion and Management: X2590-17452025-04-012610104310.1016/j.ecmx.2025.101043Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generatorQingyue Jin0Guoyao Yu1Haojie Sun2Jing Luo3Hangyu Ma4Yong Li5Shunmin Zhu6Ercang Luo7Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaKey Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; Institute of Optical Physics and Engineering Technology, Qilu Zhongke, Jinan 251000, China; Corresponding authors at: Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China.Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaKey Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; School of Mechanical Engineering, Guangxi University, Nanning 530004, ChinaKey Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaKey Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; Institute of Optical Physics and Engineering Technology, Qilu Zhongke, Jinan 251000, China; Corresponding authors at: Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China.Department of Engineering, Durham University, Durham DH1 3LE, UK; Corresponding author.Key Laboratory of Cryogenic Science and Technology, Technical Institute of Physics and Chemistry, Beijing 100190, China; University of Chinese Academy of Sciences, Beijing 100049, ChinaHeat rejection of a linear alternator (LA) plays a pivotal role in achieving high performance and a long lifetime. This paper proposes an innovative approach for the first time that utilizes a high emissivity coating formulated from a blend of microsilica and graphene nanosheets to enhance the radiation heat dissipation inside the LAs, offering advantages of structural simplicity and cost-effectiveness. To elucidate the radiative heat transfer characteristics interacted with the oscillating flow within the LA, firstly, a CFD model was developed to analyse the oscillating flow coupled radiative heat transfer within a 1.5-kW LA. The effects of coating emissivity, backdrop temperature, dissipated heat by the components, and mean pressure on the heat transfer of the LA’s electromagnetic components were investigated. Numerical calculations indicate that the high emissivity coating reduces the average temperature of the coil adjacent to the permanent magnet, the permanent magnet itself, and the inner stator by approximately 10.0 K, while the temperature of the coils adjoining the outer housing and the outer stator decreases by about 4.2 K. Additionally, the efficacy of the high emissivity coating in enhancing the cooling of these components was significantly amplified under elevated heat generation conditions. Subsequently, an experimental test rig was built and the results showed that the high emissivity coating reduces the temperature of the coil and outer stator by 1.1 K and 0.2 K, respectively, increases the output electric power by 6.6 W, and improves thermal-to-electric efficiency by 0.3 % under the operating conditions with cooling water temperature of 298 K and mean pressure of 4.5 MPa. This work provides valuable perception into enhancing the internal cooling effect of LAs.http://www.sciencedirect.com/science/article/pii/S2590174525001758Energy conversionFree-piston Stirling generatorLinear alternatorRadiative coolingConvective heat transfer |
| spellingShingle | Qingyue Jin Guoyao Yu Haojie Sun Jing Luo Hangyu Ma Yong Li Shunmin Zhu Ercang Luo Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator Energy Conversion and Management: X Energy conversion Free-piston Stirling generator Linear alternator Radiative cooling Convective heat transfer |
| title | Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator |
| title_full | Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator |
| title_fullStr | Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator |
| title_full_unstemmed | Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator |
| title_short | Experimental and numerical study on radiative cooling of a linear alternator in a free-piston Stirling electric generator |
| title_sort | experimental and numerical study on radiative cooling of a linear alternator in a free piston stirling electric generator |
| topic | Energy conversion Free-piston Stirling generator Linear alternator Radiative cooling Convective heat transfer |
| url | http://www.sciencedirect.com/science/article/pii/S2590174525001758 |
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