流体PVT的对应关系

CORRESPONDING PVT RELATION OF WORKING FLUIDS

本文依据对应态原理,提出新定义的对比压缩因子Zr=(1-Z)/(1-ZC)的无量纲交换式和对饱和温度的对比温度Tsr=T/Ts式,并根据两种流体工质对比压力Pr1=Pr2,对比温度Tsr1=Tsr2相等时,Zr1=Zr2相等的原则,导出了从一种已知PVT关系的物质推算它种物质的PVT值的通用方法。用本方法以水为标准物质推算了R12、R131、R134a、C2H4等几种物质在过热气体区、超临界区和液体区比容,计算值与文献实验值的平均偏差小于2,最大偏差小于4%。

A new corresponding compressibility factor is defined as Zr=(1-Z)/(1-Zc) in this paper. A generalized prediction method of PVT properties of interested fluids from reference fluid is presented based on corresponding-states principle that the corresponding compressibility factor Zr1=Zr2 for two different working fluids while corresponding pressure Pr1=Pr2 and corresponding temperature Tsr1=Tsr2. The values of specific volume of working fluids R12, R131, R134a and C3H8 in the super heat gas region, super critical region and liquid region are predicted while water is chosen as the reference fluid. The average error checked against reference data from literature is within 2%, and the maximum error is within 4%.