SAChE Source Models (ELA965 ) Practice Test

In the flashing liquid model, Qm represents the mass flow rate of the flashing liquid stored at its saturation vapor pressure. This is the rate at which liquid, initially at saturation pressure inside the vessel, flashes to vapor as the pressure drops. It’s a rate describing how much liquid mass per unit time is undergoing flashing, not the vapor flow rate or a volume rate, and not the total amount of liquid stored. Think of Qm as the speed at which the liquid portion that is ready to flash is leaving the liquid pool and becoming vapor.