The Spencer and Danner modification to it replaces the critical compressibility with a namesake factor unique to each component.  
The Spencer and Danner modification to it replaces the critical compressibility with a namesake factor unique to each component.  Unlike the Lee/Kessler correlation, this correlation remains accurate even for highly polar fluids, and unlike the two-parameter Lyderson-Greenkorn-Hougen correlation, does not require knowledge of the density, making it more useful near the critical point of the liquid.  Given as V-sat equals the critical volume times the critical compressibility raised to the quantity 1 minus the reduced temperature to the two sevenths power, FTP, what is this equation that can be used to estimate the molar volume of a saturated liquid?
The Spencer and Danner modification to it replaces the critical compressibility with a namesake factor unique to each component.  
Rackett equation or correlation