Transient modes in a swirl jet of superheated water

•The use of a passive swirler is an efficient means for changing the shape and structure of a boiling-up jet.•The loss of stability of the jet shape has been revealed.•It has been found that owing to the use of a passive swirler the pattern of a complete opening of the jet changes.•1/f fluctuations have been revealed in transient boiling-up regimes and changes of the jet shape. Experimental studies of boiling-up in a jet of superheated water have been carried out in the presence of a passive swirler during a discharge through a short cylindrical nozzle. The evolution of the jet disintegration of a boiling-up liquid has been traced under changes of thermodynamic parameters (temperature, pressure) along the saturation line. The characteristic structures and shapes of the jet corresponding to different modes of boiling-up have been identified. In a swirl jet 1 / f - fluctuations have been detected at both for low and for high superheats. The loss of the jet stability of superheated water under conditions of explosive boiling-up has been noted.