Experimental investigation of oil retention and pressure drop of R32/PVE oil mixture in compressor suction line
Experimental investigation of oil retention and pressure drop of R32/PVE oil mixture in compressor suction line
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DOI：
10.1016/j.ijheatmasstransfer.2021.121809
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发表时间：
2021-12
影响因子：
5.2
通讯作者：
Weijie Zeng;B. Gu;Zhongxing Du;Zhiting Zhang;Zhen Tian
中科院分区：
文献类型：
--
作者：
Weijie Zeng;B. Gu;Zhongxing Du;Zhiting Zhang;Zhen Tian
近年来，R32/PVE混合工质已成为商用制冷/热泵系统的一种常用工质对。本文对R32/PVE VG68混合工质在压缩机吸入管路中的持油特性和压降特性进行了实验研究。测试样品是两个内径为10.7mm的水平和垂直流动方向的光滑铜管。采用移去-称重法（RWT）测定了吸油管的持油率。测试了饱和温度和饱和度（7.5/12、7.5/6和10/12 ° C）的三种条件，以获得不同的热物理和传输性质。制冷剂质量通量和标称油质量分数（OMFno）分别在90 - 230 kg·m-2·s-1和1 - 5%的范围内变化。研究了制冷剂质量流量、含油率、混合物粘度和流动结构对保油率和压降的影响。结果表明，随着实际油质量分数（OMFact）和混合物运动粘度比的增大以及制冷剂质量流量的减小，油滞留量呈增大趋势。从现有文献中收集了两个关于吸油管持油率和压降的统一数据库，涉及五个工作对，以进行比较。最后，在分析原油输送机理的基础上，综合考虑了几何尺寸、工质对和操作参数对原油输送难易程度的影响，提出了一个新的表征原油输送难易程度的无量纲参数--原油滞留影响因子。与数据库和本研究的保油率数据有较好的相关性。
R32/PVE oil mixture has become a popular working pair of commercial refrigeration/heat pump systems in recent years. This paper presented experimental study of oil retention and pressure drop characteristics of R32/PVE VG68 mixture in the compressor suction lines. The test samples were two smooth copper pipes of horizontal and vertical flow orientations with 10.7mm inner diameter. The oil retention in suction lines were measured based on remove-and-weight technique (RWT). Three conditions of saturation temperature and superheat degree (7.5/12, 7.5/6 and 10/12°C) were tested, in order to obtain different thermophysical and transport properties. Refrigerant mass flux and nominal oil mass fraction (OMFno) were varied with the ranges of 90−230 kg•m−2·s−1and 1−5%, respectively. The influences of refrigerant mass flux, oil mass fraction, mixture viscosity and flow configuration on oil retention and pressure drop were investigated. The results showed that the oil retention amount tends to increase with the increases of actual oil mass fraction (OMFact) and mixture kinematic viscosity ratio and the decrease of refrigerant mass flux. Two consolidated databases for oil retention and pressure drop of suction lines, which involved five working pairs, were collected from the existing literatures to perform a comparison. Finally, based on analysis of oil transport mechanism, a new dimensionless parameter called oil retention impact factor was proposed to characterize the difficulty of oil transport, which integrated the influences of geometric dimension, working pairs and operation parameters. It showed relatively satisfactory relationship with the oil retention data from the amassed database and the present study.