{"title":"斯特林循环低温冷却器活塞路径的优化","authors":"R. Paul, K. Hoffmann","doi":"10.1515/jnet-2021-0073","DOIUrl":null,"url":null,"abstract":"Abstract The ideal Stirling cycle provides a clear control strategy for the piston paths of ideal representations of Stirling cycle machines. For non-equilibrium Stirling cycle machines however, piston paths aiming to emulate the ideal cycle’s four strokes will not necessarily yield best performance. In this contribution, we ask the question: What are the COP-optimal piston paths for specific non-equilibrium Stirling cryocoolers? To this end, we consider a low-effort Stirling cryocooler model that consists of a set of coupled ordinary differential equations and takes several loss phenomena into account. For this model and an exemplary parameter set, piston path optimizations are done with an indirect iterative gradient method based on optimal control theory. The optimizations are repeated for two different kinds of volume constraints for the working spaces: one representing an alpha-Stirling configuration, the other a beta-Stirling configuration. Compared to harmonic piston paths, the optimal piston paths lead to significant improvements in COP of ca. 88 % for the alpha-Stirling and ca. 117 % for the beta-Stirling at the maximum-COP operational frequency. Additionally—and even though the optimizations were performed for maximum COP—cooling power was increased with even lager ratios.","PeriodicalId":16428,"journal":{"name":"Journal of Non-Equilibrium Thermodynamics","volume":"47 1","pages":"195 - 203"},"PeriodicalIF":4.3000,"publicationDate":"2022-02-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"35","resultStr":"{\"title\":\"Optimizing the Piston Paths of Stirling Cycle Cryocoolers\",\"authors\":\"R. Paul, K. Hoffmann\",\"doi\":\"10.1515/jnet-2021-0073\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"Abstract The ideal Stirling cycle provides a clear control strategy for the piston paths of ideal representations of Stirling cycle machines. For non-equilibrium Stirling cycle machines however, piston paths aiming to emulate the ideal cycle’s four strokes will not necessarily yield best performance. In this contribution, we ask the question: What are the COP-optimal piston paths for specific non-equilibrium Stirling cryocoolers? To this end, we consider a low-effort Stirling cryocooler model that consists of a set of coupled ordinary differential equations and takes several loss phenomena into account. For this model and an exemplary parameter set, piston path optimizations are done with an indirect iterative gradient method based on optimal control theory. The optimizations are repeated for two different kinds of volume constraints for the working spaces: one representing an alpha-Stirling configuration, the other a beta-Stirling configuration. Compared to harmonic piston paths, the optimal piston paths lead to significant improvements in COP of ca. 88 % for the alpha-Stirling and ca. 117 % for the beta-Stirling at the maximum-COP operational frequency. Additionally—and even though the optimizations were performed for maximum COP—cooling power was increased with even lager ratios.\",\"PeriodicalId\":16428,\"journal\":{\"name\":\"Journal of Non-Equilibrium Thermodynamics\",\"volume\":\"47 1\",\"pages\":\"195 - 203\"},\"PeriodicalIF\":4.3000,\"publicationDate\":\"2022-02-09\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"35\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Non-Equilibrium Thermodynamics\",\"FirstCategoryId\":\"5\",\"ListUrlMain\":\"https://doi.org/10.1515/jnet-2021-0073\",\"RegionNum\":3,\"RegionCategory\":\"工程技术\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"MECHANICS\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Non-Equilibrium Thermodynamics","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1515/jnet-2021-0073","RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"MECHANICS","Score":null,"Total":0}
Optimizing the Piston Paths of Stirling Cycle Cryocoolers
Abstract The ideal Stirling cycle provides a clear control strategy for the piston paths of ideal representations of Stirling cycle machines. For non-equilibrium Stirling cycle machines however, piston paths aiming to emulate the ideal cycle’s four strokes will not necessarily yield best performance. In this contribution, we ask the question: What are the COP-optimal piston paths for specific non-equilibrium Stirling cryocoolers? To this end, we consider a low-effort Stirling cryocooler model that consists of a set of coupled ordinary differential equations and takes several loss phenomena into account. For this model and an exemplary parameter set, piston path optimizations are done with an indirect iterative gradient method based on optimal control theory. The optimizations are repeated for two different kinds of volume constraints for the working spaces: one representing an alpha-Stirling configuration, the other a beta-Stirling configuration. Compared to harmonic piston paths, the optimal piston paths lead to significant improvements in COP of ca. 88 % for the alpha-Stirling and ca. 117 % for the beta-Stirling at the maximum-COP operational frequency. Additionally—and even though the optimizations were performed for maximum COP—cooling power was increased with even lager ratios.
期刊介绍:
The Journal of Non-Equilibrium Thermodynamics serves as an international publication organ for new ideas, insights and results on non-equilibrium phenomena in science, engineering and related natural systems. The central aim of the journal is to provide a bridge between science and engineering and to promote scientific exchange on a) newly observed non-equilibrium phenomena, b) analytic or numeric modeling for their interpretation, c) vanguard methods to describe non-equilibrium phenomena.
Contributions should – among others – present novel approaches to analyzing, modeling and optimizing processes of engineering relevance such as transport processes of mass, momentum and energy, separation of fluid phases, reproduction of living cells, or energy conversion. The journal is particularly interested in contributions which add to the basic understanding of non-equilibrium phenomena in science and engineering, with systems of interest ranging from the macro- to the nano-level.
The Journal of Non-Equilibrium Thermodynamics has recently expanded its scope to place new emphasis on theoretical and experimental investigations of non-equilibrium phenomena in thermophysical, chemical, biochemical and abstract model systems of engineering relevance. We are therefore pleased to invite submissions which present newly observed non-equilibrium phenomena, analytic or fuzzy models for their interpretation, or new methods for their description.