Spencer-Danner method

Recommended Method Spencer-Danner-Li mixing rules with Rackett equation. 

A modification of the Rackett method by Spencer and Danner [Spencer, C. F., and R. R Danner,/. Chem. Eng. Data, 17 (1972) 236] replaces Z with an adjustable parameter Zra... 

For prediction of the densities of a defined liquid mixture at its bubble point (pi,p), the method of Spencer and Danner is the simplest. The density is calculated from Eq. (2-86) using inputs from Eqs. (2-87) and (2-88). For hydrocarbons, T is calculated by Eqs. (2-89) through (2-92) if high accuracy is desired or by Eq. (2-93) for a less accurate answer. 

---