Measurements of Transport Properties of the Environmentally Acceptable Alternatives to Fully Halogenated Chlorofluorocarbons

氟碳化合物及其混合物已被广泛用于制冷、空调、塑料泡沫发泡、清洁和灭火应用。然而，众所周知，由于新的环境后果，如对流层的温室效应和平流层的臭氧消耗，氟碳化合物的排放出现了严重的问题。因此，迫切需要寻找到目前为止使用的氟碳化合物的适当替代品。需要积累可靠的数值数据和关于这些流体的热物理性质的知识。本研究旨在获得环境可接受的新型替代制冷剂到完全卤化的氯氟烃的准确的运输性质数据。所研究的替代制冷剂是：HCFC-22(CHClF_2)、HFC-134a(CH_2F-CF3)、HFC-143a(CH_3-CF_3)、HCFC-123(CHCl_2-CF_3)、HCFC-123a(CHClF-CCIF_2)、HCFC-141b(CH_3-CCl_2F)、HCFC-142b(CH_3-CClF_2)及其非共沸二元混合物，它们可能替代CFC-11(CCL_3F)和CFC-12(CCL_2F_2)。在283~343K的温度范围内，用滚珠式粘度计测量气相粘度，用落筒式粘度计测量液体粘度，压力最高可达120 Mpa。在293-353K和100 Mpa压力范围内，用同轴圆柱室测量了气相的相对导热系数，用瞬变热线装置测量了液体的导热系数。用几种经验方法对实验数据与温度、压力和密度进行了关联。希望本文的实验结果能对替代制冷剂的选择和利用有所帮助。

Fluorocarbons and their mixtures have been used extensively in refrigeration, air conditioning, plastic foam blowing, cleaning, and fire extinguishing applications. However, serious problems have arisen, as well known, for the release of fluorocarbons in connection with the new environmental consequences, such as the greenhouse effect in the troposphere and the ozone depletion in the stratosphere. It is, therefore, an urgent need to search appropriate alternatives to fluorocarbons employed so far. The accumulation of reliable numerical data and knowledge on the thermophysical properties of these fluids is desired.The present investigation has been undertaken to obtain accurate transport property data of new environmentally acceptable alternative refrigerants to fully halogenated chlorofluorocarbons. The alternative refrigerants investigated are HCFC-22 (CHClF_2), HFC-134a (CH_2F-CF_3), HFC-143a (CH_3-CF_3), HCFC-123 (CHCl_2-CF_3), HCFC-123a (CHClF-CCIF_2), HCFC-141b (CH_3-CCl_2F), HCFC-142b (CH_3-CClF_2), and their non-azeotropic binary mixtures which are potential replacements of CFC-11 (CCl_3F) and CFC-12 (CCl_2F_2). The viscosity measurements were performed with a rolling-ball viscometer in the gas phase and with a falling-cylinder viscometer in the liquid phase in a temperature range from 283 to 343 K under pressures up to 120 MPa. The thermal conductivity has been measured with a coaxial-cylinder cell on a relative basis in the gas phase and with a transient hot-wire apparatus in the liquid phase at temperatures from 293-353 K and pressures up to 100 MPa. The experimental data obtained have been correlated with temperature, pressure and density by several empirical methods. The author hopes that the present experimental results may contribute to the selection and utilization of alternative refrigerants.