A numerical technique for low-speed homogeneous two-phase flow with sharp interfaces

A numerical method is presented for calculating the transient flow of a homogeneous two-phase (gas-liquid) fluid at small Mach numbers. The method is Eulerian and is applicable in one, two, or three space dimensions. The density ratio of the two phases may be arbitrarily large, enabling the important special case of steam-water flow at low pressures to be treated. The phase interface is resolved by using a modified donor-acceptor differencing technique for computing mass transport. Inaccuracies resulting from slightly inconsistent calculations of mass and energy transport are avoided by converting the energy equation into a form which does not involve a convective derivative. A nonconservative form of the momentum equation is utilized because velocity is typically a smoother function than momentum density when the phase density ratio is large. The results of two sample calculations are presented.