R125表面张力的实验研究

Experimental Research on Surface Tension of R125

为适应国际上即将禁用CFC和HCFC类物质的迫切要求 ,寻找其替代物成为当务之急。R12 5是一种对臭氧层无破坏作用的新替代物 ,在目前国际上所提出的R2 2的混合工质替代物中是必不可少的组分之一。表面张力是分析计算有相变换热问题所需要的基本热物性参数。本文使用毛细管法实测了从 2 4 8K到 32 3K温度范围内 4 0组R12 5表面张力实验数据 ,温度不确定度小于± 10mK ,表面张力的不确定度为± 0 .1mN·m- 1。综合本文及文献的实验数据 ,拟合了R12 5表面张力随温度变化的关联式。

To meet the restriction of the Montreal protocol,a hydrofluorocarbon (HFC) whose ozone depletion potential (ODP) value is zero to replace chlorofluorocarbon (CFC) and hydrochlorofluorocarbon (HCFC) should be looked for. The binary and/or ternary mixtures using R125 as a component are thought to be the most promising alternatives for R22. Surface tension is a basic thermophysical property,especially with respect to heat transfer through a heat exchanging surface with bubbles of fluid drops on it. The surface tension of R125 has been measured in the present work.Forty data points have been obtained by differential capillary rise method (DCRM) in the temperature range from 248 to 323 K. The temperature uncertainty is within ±10mK. The accuracy of surface tension measurements is estimated to be within ±0.1mN·m -1 .The correlation of surface tension for R125 also has been proposed