**2.3 Water circulation mode**

The role of the water circulation or the emulsion of water and steam in the steam boiler tubes is to ensure, on the one hand, the correct cooling of the tubes located in the hottest areas or exposed to radiation and that receives at this part the maximum heat flow and, on the other hand, to ensure the generation of saturated steam, that is to say, the passage of the heated fluid from the water state to the water and vapor emulsion state. There are two main types of circulation, natural circulation and forced circulation.
