非卡诺制冷机在最大品质因子下的制冷系数  

Coefficient of Performance at Maximum Figure of Merit for Non-Carnot Refrigerators

作　　者：肖宇玲[1] 张艳超[1] 何济洲[1] 

机构地区：[1]南昌大学物理系,南昌330031

出　　处：《机械工程学报》2013年第24期161-166,共6页Journal of Mechanical Engineering

基　　金：国家自然科学基金资助项目(11365015)

摘　　要：非卡诺制冷机是由两个多方过程和两个绝热过程组成。假设传热过程服从牛顿传热规律,推导出制冷机的制冷率和制冷系数的表达式,得到制冷率与制冷系数之间满足的特征曲线。通过数值模拟研究在最大品质因子下制冷机的制冷系数。分析在长时间和短时间热接触条件下制冷系数的优化值,并与经典的Curzon-Ahlborn(CA)制冷系数进行比较。结果表明,在长时间热接触极限下,高低温热接触过程中工质的热容之比λ=1时,优化制冷系数为CA制冷系数;λ<1时,优化制冷系数小于CA制冷系数;λ>1时,优化制冷系数大于CA制冷系数。而在短时间极限下,在λ=1时,优化制冷系数大于CA制冷系数。在所有情形下,优化制冷系数随着热容比λ的增大而增大。这个模型可以应用到Otto、Joule-Brayton、Dissel和Atlinson热力学循环,这可以为设计实际的制冷机提供指导。The non-Carnot refrigerators are composed of two polytropic and two adiabatic processes. It is assume that Newton＇s heat transfer law is obeyed during heat transfer processes, the expressions for.the coefficient of performance（COP） and cooling rate of the refrigerator are derived. The characteristic curves between the cooling rate and the COP are plotted. Moreover, the optimal COP of the refrigerators at maximum figure of merit are analyzed by the numerical calculation and graphic method. The optimal COP is analyzed at two special limit cases of long and short contact times, and compared with that of the classical Curzon-Ahlborn COP. The results show that, for the long thermal contact time limit, the optimal COP is equal of the CA COP when the ratio of heat capacity -- 1 between the heat capacities of the working medium during hot and cold contact process. In the case of λ 〈 1, the optimal COP is less than the CA COP, however, in the case of λ 〉 1, the optimal COP is larger than the CA COP. For the short contact time limit, the optimal COP is larger than the CA COP whenλ = 1. In both cases, the optimal COPs increases as the heat capacities ratio λ increases. This model can be applied to Otto, Joule-Brayton, Dissel and Atlinson thermodynamic cycles. This might provide guidance for designing real refrigerators.

关 键 词：非卡诺制冷机 品质因子 牛顿传热规律 有限时间热力学 性能优化 

分 类 号：O414[理学—理论物理]