The vaporization nozzle (1) is formed by a nozzle body (10) including a first pressurized gas intake perforation (11), and at least one second perforation (12) for intake of a liquid to be fractionated, in communication with the first perforation, and a liquid vaporization zone (13), formed in the axis of the first perforation (11). This nozzle is noteworthy in particular in that the or each intake perforation (12) of the liquid is in communication with the first perforation (11) through an underpressure chamber (15) that is formed between the first perforation and the vaporization zone, with the propellant gas stream passing all the way through the depression chamber (15).
