about the volume integral
 

Hello everyone, I simulate Mixture Multiphase Flow. When I calculated the mass of each phase in a curtain selected cell zone by volume integral of density of each phase. In this cell zone, physically there is no phase 2. Unforturnately, I also can find the same mass value (same mass value as phase 1) for phase 2 appearing in this selected cell zone. Does someone know what is wrong? Thanks. Zwdi