１引言臭氧层破坏和全球气候变暖，是当前世界所面临的主要环境问题之一。“天然工质”作为制冷剂，在近２０年里已重新引起了人们的关注。许多碳氢化合物作为天然制冷剂具有良好的热物理特性，但它们的缺点在于其可燃性。因此，对碳氢化合物进行研究讨论，就成了当前制冷行业 1 Introduction Ozone destruction and global warming are one of the major environmental problems facing the world today. As a refrigerant, “natural working fluid” has regained attention in the past 20 years. Many hydrocarbons have good thermophysical properties as natural refrigerants, but their disadvantage is their flammability. Therefore, research and discussion of hydrocarbons has become the current refrigeration industry