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一、引言临界性质是流体最基本的性质之一,它对了解流体的热力状态面以及用对应态原理来外推流体的其它热力性质都有重要的意义。目前,国际上日趋重视氯氟烃(CFCs)用作制冷剂、发泡剂等时对大气环境的破坏作用,各国均在加紧替代物的研究。用实验方法精确确定流体的临界参数已成为正确筛选氟里昂替代物的关键技术之一。由于流体在临界点的特殊性质,使得临界参数的测量具有一定难度。本文经仔细考虑,设计了一套用临界乳光法测定流体临界区性质的实验装置,用大容量高精度恒温槽,对国产氟里昂R22、R152a和R502进行了测定。
I. INTRODUCTION The critical nature is one of the most basic properties of a fluid. It is of great importance to understand the thermal state of a fluid and to extrapolate the fluid’s other thermodynamic properties by the principle of corresponding states. At present, the international community has paid increasing attention to the destructive effects of CFCs on the atmospheric environment when used as refrigerants, blowing agents and the like, and all countries are stepping up their studies on alternatives. Accurately determining the critical parameters of a fluid using experimental methods has become one of the key technologies for the correct screening of Freon surrogates. Due to the special nature of the fluid at the critical point, making the measurement of critical parameters has a certain degree of difficulty. After careful consideration, a set of experimental apparatus for determining the criticality of fluid by critical opalescence was designed. The domestic Freon R22, R152a and R502 were measured with large-capacity and high-precision thermostat.