Experimental investigation on pressure oscillation frequency for submerged sonic/supersonic steam jet

Experimental investigations and analysis on the pressure oscillation frequency for sonic and supersonic steam injected into subcooled water have been performed. The effects of steam mass flux, water temperature and pressure ratio on the oscillation frequency are discussed. The penetration length increases and the frequency decreases with the increasing steam mass flux and water temperature for both sonic and supersonic steam injection. The frequency first increases and then decreases with the decreasing pressure ratio for supersonic steam injected into subcooled water. When the flow pattern changes from under-expanded jet to over-expanded jet with the decreasing pressure ratio, the frequency reaches a maximum and will be at the safest value. The safest pressure ratio is about 0.2 for supersonic steam injection. The correlation reported by previous scholars cannot be directly used to predict the frequency of supersonic steam injected into subcooled water. Based on our experimental data, penetration length and expansion coefficient correlations which are appropriate for the supersonic steam injection have been given. Using the given penetration length and expansion coefficient correlations, the correlation of Hong can be used to predict the oscillation frequency for supersonic steam injection. The predictions agree well with the present experimental data, the discrepancies are within −20% ∼ 20%.