Critical equilibrium two-phase flow with quasi-constant slip

On the basis of the mass-, momentum- and energy-conservation equations, assuming a quasi-constant slip, a mathematical model of the critical non-homogeneous equilibrium two-phase flow is developed. The slip is varied to find the maximum of the critical mass flow rate for low qualities. For qualities greater than 0.1 it is found that the critical mass flow rate has no extreme values and approaches a constant value when the slip increases. Following the concept of Henry and Fauske the model is extended to describe non-homogeneous non-equilibrium two-phase flows, too. The comparison with published experimental data demonstrates that the theory can approximate well different experimental results on determination of the local critical mass flow rate. (orig.)