DYNAMICAL PRESSURE PULSE IN STEAM JET CONDENSATION
The dynamical pressure pulse of a steam jet in sub-cooled water has been measured as a function of steam jet sizes and subcooled water temperature. Steam was injected downward through nozzles of different diameters placed in the middle of the test chamber, which contains water maintained at various temperatures. It was observed from the high speed movie that the steam jet was unstable. Kelvin-Helmoltz instability was observed to be dominant at the vapor-liquid interface. The jet diameter also oscillated as a result of simultaneous steam supply and vapor condensation. The jet diameter grew with elevated water temperatures. The frequency of the pressure pulse increased inversely with nozzle diameter at low subcooled water temperature but it reached a constant value corresponding to the test chamber eigen-frequency after a threshold temperature. The pulse magnitude increased with the water temperatures at the beginning, then it reached a peak, then decreased before the water reached saturation temperature.