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回热损失对磁斯特林制冷循环制冷率的影响 总被引:7,自引:0,他引:7
从铁磁质的磁化强度一般表示式出发,探讨热阻和回热损失对磁斯特林制冷循环性能的影响,导出最大制冷率及其它性能参数。得到了结果适用于以顺磁质为工质的磁斯特林制冷循环。并指出在理想回热条件下的结论也适用于磁卡诺制冷循环。 相似文献
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磁布雷顿制冷机优化循环性能及参数设计 总被引:1,自引:0,他引:1
基于统计力学和磁工质的热力学性质,建立磁布雷顿制冷机循环新模型,探索热漏、有限速率热传导,绝热过程不可逆性和绝热时间等对循环性能的影响,应用对数平均温差及热力学分析方法,导出制冷率、性能系数的数学表式,并应用数值方法分析、评估磁布雷顿制冷循环的优化性能特性,所得结果为磁制冷机的优化设计和性能改善提供参数设计参考。 相似文献
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室温磁制冷作为一种高能效、环境友好和运行可靠的制冷技术,具有广阔的应用前景。室温磁制冷技术利用磁工质的磁热效应以及AMR循环实现制冷。在过去数十年的探索中,室温磁制冷的研究主要集中于磁工质的研发和磁制冷机的设计。本文综述了目前已开发的几种典型的室温磁工质以及研制的磁制冷样机。目前研究较丰富的室温磁工质主要包括稀土金属Gd及其合金、NaZn13型La(Fe, Si)13系合金以及Fe2P型MnFePAs系合金,本文对它们的磁热性能进行对比并分析存在的实际应用问题。基于运行方式的不同,目前研制的磁制冷样机主要分为往复式和旋转式,介绍了不同研究机构研发的磁制冷样机的实验参数与制冷性能。回顾了室温磁制冷技术在不同领域已取得的实际应用,并对该技术未来的发展趋势进行展望。 相似文献
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用混合铁磁工质改善磁埃里克森制冷循环的回热性能 总被引:2,自引:0,他引:2
根据磁性材料的比热和熵的特性,讨论了采用混合铁巴工质可使磁埃里克森制冷循环实现理想回热或趋近于理想回热,而用混合顺磁工质则难达此目的.实验上也得到了相同的结论. 相似文献
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Based on the thermodynamic properties of a paramagnetic salt, an irreversible model of the magnetic Brayton refrigeration cycle is established, in which the working substance is a special paramagnetic material. The expressions of the important performance parameters, such as the coefficient of performance, refrigeration load and work input, are derived. Moreover, the optimal performance parameters are obtained at the maximum coefficient of performance. The results obtained here may include the ones of the magnetic Brayton refrigeration cycle using the magnetic material obeyed the Curie law as the working substance, the magnetic Brayton refrigeration cycle without regeneration and the eversible magnetic Brayton refrigeration cycle. Therefore, the results obtained here have general significance and will be helpful to deeply understand the performance of a magnetic Brayton refrigeration cycle. 相似文献
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应用有限时间热力学理论,建立铁磁斯特林制冷循环模型,考虑有限速率热传导、回热损失和回热时间等因素,基于铁磁材料的热力学性质,导出铁磁斯特林制冷循环的优化性能,进而研究热阻及回热损失对铁磁斯特林制冷机生态学优化性能的影响,所得结论可为铁磁斯特林制冷机的研制和设计提供理论指导. 相似文献
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磁布雷顿制冷循环性能的优化分析 总被引:2,自引:0,他引:2
基于统计力学的性质推导出了顺磁系统的热力学关系,并构建了以满足居里定律的顺磁材料为工作物质的一般磁布雷顿制冷循环模型。研究了内不可逆性和传热不可逆性对循环优化性能的影响。根据该循环模型,推导出了循环的各种优化关系并深刻讨论了循环的性能特性,所得结果将有助于实际的磁制冷机的优化设计和应用。 相似文献
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Z.G. Zheng H.Y. Yu X.C. Zhong D.C. Zeng Z.W. Liu 《International Journal of Refrigeration》2009,32(1):78-86
A room-temperature magnetic refrigerator, consisting of permanent magnet, active magnetic refrigeration (AMR) cycle bed, pumps, hydraulic circuit, active magnetic double regenerator cycle (AM2RC) and control subsystems, has been designed. The magnetic field is supplied by NdFeB permanent magnets. The AMR bed made by stainless steel 304 encloses gadolinium particles as the magnetic working substance. Each part of the refrigerator is controlled by the programmable controller. The different standard heat exchangers are employed to expel heat. The cycle performance of this self-designed facility is analyzed using Langevin theory. The results provide useful data for future design and development of room-temperature magnetic refrigeration. 相似文献
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不可逆四热源制冷循环的优化性能 总被引:2,自引:0,他引:2
研究传热遵从线性唯象律的不可逆四热源制冷循环的优化性能,导出循环的基本优化关系和最大制冷率及其相应的制冷系数.揭示了四热源制冷循环等效于一个三热源制冷循环,而且还可使四热源制冷循环转化为一个三热源制冷循环而获得更优的制冷效果. 相似文献
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联合制冷循环的有限时间热力学 总被引:1,自引:0,他引:1
研究由两个内可逆卡诺制冷循环构成的无中间热源的联合制冷循环有限时间热力学最优性能。基于一类较为普遍的物理模型,导出其制冷量与制冷系数间的基本关系,再根据活塞式模型循环和定常流模型循环的基本特征,得到两种模型联合到冷循环的最佳制冷率密度与制冷系数间的关系。对前者,与前人所得结果相同;对后者,获得了一些新的有意义的结论。有关结果还可推广到由两个以上制冷循环构成的联合制令循环。 相似文献
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A finite-time thermoeconomic performance analysis based on a new kind of optimization criterion has been carried out for a two-stage endoreversible combined refrigeration cycle model. The optimal performances and design parameters that maximize the objective function (cooling load per total cost) are investigated. In this context, the optimal temperatures of the working fluids, the optimum performance coefficient, the optimum specific cooling load and the optimal distribution of the heat exchanger areas are determined in terms of technical and economical parameters. The effects of the economical parameter that characterizes the investment and energy consumption costs on the general and the optimal performances have been discussed. 相似文献
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The cycle model of an irreversible regenerative magnetic Brayton refrigerator using Gd0.74Tb0.26 as the working substance is established. Based on the experimental characteristics of iso-field heat capacities of the material Gd0.74Tb0.26 at 0 T and 2 T, the corresponding iso-field entropies are calculated and the thermodynamic performance of an irreversible regenerative magnetic Brayton refrigeration cycle is investigated. The effects of the irreversibilities in the two adiabatic processes and non-perfect regenerative process of the magnetic Brayton refrigeration cycle on the cooling quantity, the heat quantity released to the hot reservoir, the net cooling quantity and the coefficient of performance are discussed in detail. Some significant results are obtained. 相似文献