饱和气液相密度关联外推的新通用对比态方程OA

Saturated density,a key thermophysical property of fluids at vapor-liquid equilibrium,is widely used in power cycles and chemical processes.However,experimental data of saturated density are often scarce and scattered;consequently,developing a correlation equation that accurately reproduces existing measurements while providing reliable extrapolation is essential.In this work,based on the thermodynamic similarity between saturated density and saturated vapor pressure,the previously proposed three-parameter saturated vapor pressure equation is extended to saturated density.The functional form is preserved,ensuring positive density and correct limiting behavior toward the critical point and triple point.Using thirty-two substances that possess abundant experimental data,the new equation is compared with the Zhang equation and Wagner equation.The results demonstrate that,with respect to correlation,the deviations of the new equation are of the same magnitude as those of the Zhang equation and Wagner equation and lie within the reported experimental uncertainties.In terms of extrapolation,the new equation is superior to or equivalent to the Zhang equation and Wagner equation,exhibiting a more stable and accurate extrapolation trend.Further improvement in the stability and accuracy of the extrapolation trend can be achieved by fixing some parameters of the new equation during extrapolation fitting.