Principle of steam-water mixed heater?

Sem _QSH steam-water mixing heater consists of core tube (Raphael nozzle) and shell. There are many inclined holes in the wall of the core tube. The relatively small part of the inlet end of the core tube is the throat, the middle part is the mixed heating zone, and the steam zone is between the core tube and the shell. During the pipeline operation, cold water is injected into the heating zone at high speed from the throat, while steam is injected into the heating zone at high speed from the inclined hole of the core pipe, and the steam and water are mixed for heat exchange to generate hot water.