PRECISE MEASUREMENTS OF PρT AND SATURATION PROPERTIES FOR NATURAL WORKING FLUIDS IN HIGH TEMPERATURES AND PRESSURES

摘要

We report our results of PρT and saturation property measurements for isobutane and propane by means of a metal-bellows variable volumometer in the temperature range from 280 K to 440 K at pressures up to 200 MPa. The expanded uncertainties (k=2) in temperature, pressure, and density measurements have been estimated to be less than 3 mK, 1.5 kPa-0.2%, and 0.11%-0.23%, respectively. Throughout the present study, we observed the reproducibility of the available equations of state to the present measurements for hydrocarbons in the ranges over the range of validity of the models, from which the necessity of the improvements for the available models can be confirmed.