R134a通过短管流动的试验研究

Experimental Investigation of R134a Through Short Tube Orifices

短管机构在汽车空调、家用空调和热泵系统中得到越来越广泛的应用。目前，关于提供通过短管机构ＣＦＣ替代物性能研究方面的数据很少。本文给出了ＣＦＣ替代物Ｒ１３４ａ通过短管机构的流动特性试验研究。在很宽的操作条件下，通过试验研究了Ｒ１３４ａ流过短管机构的性能参数变化。长径比在７～２０范围内，冷凝温度为３５℃～５４℃时，过冷度可达１３．９℃，短管入口干度可达１０％左右。对进入短管的两相流和过冷液体性能进行了测试，可以看出，通过短管机构的制冷剂流动性质取决于上游过冷度、上游压力、下游压力、短管直径和长度。

Short tube orifices have been widely used as a expansion device on automotive.residential sized air conditioners and heat pump system. Very little data are available on how any of the new replacement refrigerants will perform in short tube orifices relative to conventional refrigerants. This paper submitted two-phase flow investigution of new replacement refrigerant R134a through short tube orifices.Performance and parameter variations of short tube orifices for pure R134a are studied at wide operating conditions. The two-phase and subcooling flow performances were tested for L/D ratios from 7 to 20, for condensing temperature range from 35℃ to 54℃, for subcooling as high as 13.9℃ and for qualities as high as 10% at the inlet of the short tube. The refrigerant flow characteristics through short tabe orifices depend on the upstream subcooling, upstream pressure, downstream pressure , short tube diameter and length.