Inlet quality

When inlet quality is set to zero this essentially represents 100% liquid. In that case, we would usually model the system as a liquid flow system and set the pressure and temperature of the liquid. If you wish to model as two phase, you can increase the quality at the inlet ever so slightly to a value such as say, 0.05 to instigate two-phase flow conditions at the inlet. When you the solve the model, you will get more reasonable results. (Likewise, if you modeled the system with an inlet quality of 1, it would essentially be 100% gas and we would tend to model a gas flow system by setting the pressure and temperature at the inlet as opposed to vapor quality) Note, the mass flow is constants and consistent throughout the model however, the volumetric flow rate will change de to changes in fluid density etc.