title: A new grand canonical ensemble method to calculate first-order phase transitions.
abstract: A theory about first-order phase transition of pure fluids is proposed. The theory is developed by combining grand canonical ensemble with density functional for homogeneous fluids. It is based on the fact that the grand partition function of one macroscopic volume is the product of the grand partition functions of its subvolumes. Density fluctuations of molecules determine the relation between the grand partition function and the free energy density. By combining pairs of subvolumes successively, the free energy density is transformed and rapidly becomes stationary. The stationary curve versus molecule density is convex and its linear segments represent phase transitions. The transform leads to the new grand canonical method to calculate phase equilibrium, which is more robust than classic ones. The transform suggests that classical van der Waals loop is physical and essential to phase transition.
authors.affiliation: Honeywell Process Solutions, 300-250 York St., London, Ontario N6A 6K2, Canada. yiping.tang@honeywell.com
authors.forename: Yiping
authors.initials: Y
authors.lastname: Tang