空调工况下非共沸制冷剂在蒸发器内的传热窄点研究  

Pinch point of zeotropic refrigerants in evaporator with air-conditioning operation

作　　者：赵力[1] 朱禹[1] 王晓东[1] 

机构地区：[1]天津大学机械工程学院热能系,天津300072

出　　处：《低温工程》2007年第4期51-55,共5页Cryogenics

基　　金：国家自然科学基金(50476062)项目;北京市重点实验室开放基金(KF200606)项目

摘　　要：为了揭示15种常用非共沸制冷剂在空调工况下蒸发器中的传热窄点特征,探明它们和换热流体间温差的沿程变化规律,以及如何防止传热窄点的产生进行了理论分析,建立了制冷剂的蒸发换热模型,明确了蒸发过程中传热窄点产生的条件,并根据标准的空调工况确定了15种制冷剂的蒸发物性参数;然后,利用制冷剂状态方程得到蒸发过程中温度与焓值的对应关系,并分段计算了焓随温度的变化率进而得到15种制冷剂蒸发过程中发生传热窄点现象的机率;以R409A和R407D为例,计算了制冷剂和换热流体在蒸发过程中的温度分布;最后针对2种可能发生传热窄点现象的制冷剂给出了换热流体温差控制范围。To reveal heat transfer pinch point characters of zeotropic refrigerants in evaporator with air- conditioning operation, understand the rule of temperature difference（between refrigerant and heat-transfer fluid） changing and avoid the pinch point, some researches were carried out. A refrigerants evaporating model was built to obtain the occurring condition of pinch point. Fifteen kinds of refrigerants situation parameter were decided for air-conditioning operation. Secondly, the situation equation of refrigerants was used for computing and obtaining the relationship between temperature and enthalpy, including （dh/dt） p and the probability of occurring pinch point about fifteen kinds of refrigerants was achieved. As examples, R409A and R407D were presented temperature profiles of refrigerant and water in a evaporator operation. Finally, heat-transfer fluid＇ s ranges of temperature difference between evaporator inlet and outlet were presented to avoid occurring pinch point in these refrigerants.

关 键 词：非共沸制冷剂 蒸发 传热窄点 空调工况 

分 类 号：TB612[一般工业技术—制冷工程]