本文开发了测量高温高压H2-CO2-H2O混合物状态方程的定容-膨胀组合法,温度和压力的测量范围可达到 650℃.22 MPa.采用定容过程可实现混合物温度和压力变化的快速测量,采用多次膨胀过程可测量工质质量.本方法可避免高温下氢气渗漏,准确测定工质质量.不确定度分析结果表明,温度、压力、密度测量的不确定度分别不超过10 mK、0.9％和0.5％.“,”In this paper, an Isochoric-Burnett combination method has been proposed to measure the PVT properties of H2-CO2-H2O mixture at high temperatures and high pressures up to 650℃ and 22 MPa. A fast isochoric measurement process has been used to handle the problem of hydrogen leakage at high temperatures and a series of expansion measurement processes have been used to obtain the mass of the gas mixture. This method can avoid the leakage of hydrogen at high temperatures and obtain the mass of the gas mixture precisely. The uncertainty analysis shows that uncertainties of temperature, pressure and density data are not above 10 mK, 0.9％ and 0.5％.