The flow of a liquid-vapor mixture through a duct

The critical and subcritical mass flow rate is calculated for a homogeneous, adiabatic, frozen, liquid-vapor mixture flowing through a vent with friction. A critical pressure ratio (defined based on the simplifying assumptions) and other fluid dynamic parameters are calculated. The model is an extension of the compressible, adiabetic, constant duct area gas dynamics equations with wall shear. In spite of the limiting assumptions, the model is in agreement with experimental data and other critical flow analytical models. The model is capable of predicting a critical pressure ratio, predicting flow rate for critical or subcritical flow, predicting all fluid properties of interest for either critical or subcritical flow, and the model employs a sonic velocity expression consistent with the assumptions. This model has been successfully employed to aid in predicting the pressure transients of nuclear reactor subcompartments following a postulated loss-of-coolant accident.