Effect of lubricating oil on the flow and heat transfer characteristics of supercritical carbon dioxide
Effect of lubricating oil on the flow and heat transfer characteristics of supercritical carbon dioxide
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DOI：
10.1016/j.ijrefrig.2012.03.015
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发表时间：
2012-08
期刊：
影响因子：
--
通讯作者：
C. Dang;K. Hoshika;E. Hihara
中科院分区：
文献类型：
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作者：
C. Dang;K. Hoshika;E. Hihara
通过使用PAG、PVE和ECP三种润滑剂，研究了润滑油对超临界CO2传热性能的影响。传热系数测量和流型可视化是在 2mm 内径的水平管中进行的。二氧化碳压力为 8 至 10MPa，质量通量为 800 至 1200kgm−2s−1。研究发现润滑剂与 CO2 的溶解度对流动模式和传热系数有显着影响。对于 CO2 溶解度最高的 PVE，在低于 Tpc 的温度下只能偶尔观察到油滴，几乎无法识别油膜，并且传热系数随油浓度变化不大。在较高温度下，由于油膜的形成，所有三种润滑剂的传热系数都随着油浓度的增加而降低。实验表明，虽然 ECP 不如 PVE，但它提供了比 PVG 更好的传热性能。
Effects of lubricating oil on heat-transfer performance of supercritical CO2were studied by applying three lubricants: PAG, PVE, and ECP. Heat-transfer coefficient measurements and flow-pattern visualization were conducted in a horizontal tube of 2mm I.D. at CO2pressures from 8 to 10MPa and mass fluxes from 800 to 1200kgm−2s−1. The solubility of lubricants with CO2was found having remarkable influence on both the flow pattern and heat-transfer coefficient. For PVE, which has the highest CO2solubility, oil droplets can only be observed occasionally and the oil film can hardly be identified at temperatures lower than Tpc, and the heat-transfer coefficient does not greatly change with oil concentration. At higher temperatures, a decrease in the heat-transfer coefficient with increasing oil concentration was observed for all three lubricants due to the formation of oil film. The experiments show that while ECP is inferior to PVE, it provides better heat-transfer performance than PVG.