Abstract:

The separation efficiency of mixtures refrigerant is a main factor affecting the performance of auto-cascade refrigeration cycles. Fractionation purifies low-boiling compositions while reducing the mass flow rate in the evaporator, which may lead to a decrease in cycle performance. This article proposes a cycle that combines fractionation and flash separation. The cycle increases the refrigerant flow rate and purifies the compositions. The thermodynamic analysis results show that under the design conditions, the mass fraction of low-boiling compositions and refrigerant mass flow rate in the new cycle is increased by 5.37% and 17.80% compared to the basic cycle. The mass flow rate within the evaporator in the fractionation cycle decreased by 11.6%. The COP and efficiency of the new cycle are increased by 26.33% and 26.05% compared to the basic cycle. Therefore, the combination of fractionation and flash separation improves the performance of the auto-cascade cycle.

Key words: auto-cascade refrigeration, mixture, separation, thermodynamic

摘要：

混合物制冷剂的分离效率是影响自复叠制冷循环性能的关键因素。分馏分离净化低沸点组分的同时减少了蒸发器内的制冷剂流量，可能造成循环性能的下降。提出一种分馏和闪蒸分离结合的自复叠制冷循环，在净化组分的同时增加了蒸发器内制冷剂流量。热力学分析结果表明，在设计工况下，新型循环蒸发器内低沸点组分质量分数和制冷剂质量流量相比基本循环分别提升5.37%和17.80%，分馏循环内蒸发器流量降低11.6%，新型循环的制冷系数（COP）和㶲效率相比基本循环分别提高26.33%和26.05%，分馏与闪蒸分离的结合形式提高了自复叠制冷循环性能。

关键词: 自复叠制冷, 混合物, 分离, 热力学