Effect of phase behavior,density,and isothermal compressibility on the constant-volume heat capacity of ethane+n-pentane mixed fluids on different phase regions

摘要

The phase behavior,density,and constant-volume molar heat capacity (C_(v,m)) of ethane+n-pentane binary mixtures have been measured in the supercritical region and subcritical region at T=309.45 K.In addition,the isothermal compressibility (K_T) has been calculated using the density data determined.For a mixed fluid with a composition close to the critical composition,C_(v,m),and k_T increase sharply as the pressure approaches the critical point (CP),the dew point (DP),or the bubble point (BP).However,C_(v,m) is not sensitive to pressure in the entire pressure range if the composition of the mixed fluid is far from the critical composition.To tune the properties of the binary mixtures effectively by pressure,both the composition and the pressure should be close to critical point of the mixture.The intermolecular interactions in the mixture are also discussed on the basis of the experimental results.