Numerical study on pressure oscillations amplitude distribution induced by water flow into pipe filled with steam

The direct contact condensation (DCC) between subcooled water and steam is an important thermo-hydraulic phenomenon experienced in industrial sectors especially in nuclear industry. The pressure oscillations are inevitable events during steam-water DCC involving high pressure peaks, responsible for the possible failure of mechanical equipment and systems. This computational fluid dynamics study explores the underlying physics of condensation pressure oscillations by injecting subcooled water into steam section. Based on the probability density function (PDF) approach, the effects of different parameters such as velocity and temperature of injected water, water-steam differential pressure and degree of superheated steam on the amplitude of pressure oscillations distribution have been studied. Moreover, the first and second dominant frequencies of pressure oscillations have also been obtained from fast Fourier transform. It has been found that the PDF of the pressure oscillations is strongly related to injecting water velocity, water temperature and steam-water differential pressure while weakly dependent on steam superheating.