Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing
The free-piston Stirling engine is a closed-cycle regenerative heat engine that converts heat energy into mechanical work, and requires a spring element for vibratory operations of the displacer and power pistons. In this study, the geometry of the flexural spring design was optimized through struct...
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| Format: | Article |
| Language: | English |
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MDPI AG
2021-08-01
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| Series: | Energies |
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| Online Access: | https://www.mdpi.com/1996-1073/14/16/5156 |
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| author | Chang-Whan Lee Dong-Jun Kim Sung-Kwon Kim Kyuho Sim |
| author_facet | Chang-Whan Lee Dong-Jun Kim Sung-Kwon Kim Kyuho Sim |
| author_sort | Chang-Whan Lee |
| collection | DOAJ |
| description | The free-piston Stirling engine is a closed-cycle regenerative heat engine that converts heat energy into mechanical work, and requires a spring element for vibratory operations of the displacer and power pistons. In this study, the geometry of the flexural spring design was optimized through structural finite element analyses and fatigue test evaluations. First, we constructed a target design space considering the required natural frequency of the displacer spring assembly under the geometric constraints of total mass and module height. The design of experiments was employed to construct simulation cases for design factors such as the outer diameter, thickness, and number of spirals in the spring sheet. As a result, the optimized design values were obtained to satisfy the design requirements. We also fabricated a test spring specimen and conducted fatigue tests using a linear actuator system developed to have the same motion as the engine. The test results indicated that the optimized spiral spring had no fracture under operating conditions with the design piston amplitude, revealing the effectiveness of the design method. |
| first_indexed | 2024-03-10T08:51:00Z |
| format | Article |
| id | doaj.art-bb4cb5c61cf84f43b8d69002fcaecd0a |
| institution | Directory Open Access Journal |
| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-10T08:51:00Z |
| publishDate | 2021-08-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-bb4cb5c61cf84f43b8d69002fcaecd0a2023-11-22T07:32:47ZengMDPI AGEnergies1996-10732021-08-011416515610.3390/en14165156Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue TestingChang-Whan Lee0Dong-Jun Kim1Sung-Kwon Kim2Kyuho Sim3Department of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, KoreaDepartment of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, KoreaDepartment of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, KoreaDepartment of Mechanical System Design Engineering, Seoul National University of Science and Technology, Seoul 01811, KoreaThe free-piston Stirling engine is a closed-cycle regenerative heat engine that converts heat energy into mechanical work, and requires a spring element for vibratory operations of the displacer and power pistons. In this study, the geometry of the flexural spring design was optimized through structural finite element analyses and fatigue test evaluations. First, we constructed a target design space considering the required natural frequency of the displacer spring assembly under the geometric constraints of total mass and module height. The design of experiments was employed to construct simulation cases for design factors such as the outer diameter, thickness, and number of spirals in the spring sheet. As a result, the optimized design values were obtained to satisfy the design requirements. We also fabricated a test spring specimen and conducted fatigue tests using a linear actuator system developed to have the same motion as the engine. The test results indicated that the optimized spiral spring had no fracture under operating conditions with the design piston amplitude, revealing the effectiveness of the design method.https://www.mdpi.com/1996-1073/14/16/5156free-piston Stirling enginethermal cycledesign optimizationfatigue testingflexure spring |
| spellingShingle | Chang-Whan Lee Dong-Jun Kim Sung-Kwon Kim Kyuho Sim Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing Energies free-piston Stirling engine thermal cycle design optimization fatigue testing flexure spring |
| title | Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing |
| title_full | Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing |
| title_fullStr | Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing |
| title_full_unstemmed | Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing |
| title_short | Design Optimization of Flexure Springs for Free-Piston Stirling Engines and Experimental Evaluations with Fatigue Testing |
| title_sort | design optimization of flexure springs for free piston stirling engines and experimental evaluations with fatigue testing |
| topic | free-piston Stirling engine thermal cycle design optimization fatigue testing flexure spring |
| url | https://www.mdpi.com/1996-1073/14/16/5156 |
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