Experimental investigation on the condensation regime and pressure oscillation characteristics of vertical upward steam jet condensation with low mass flux

Abstract

An experimental study was conducted to investigate the condensation regime and pressure oscillation characteristics of vertical upward steam jet condensation with low mass flux. Steam mass flux and water temperature were 8.34–16.71 kg/(m2·s) and 40–85 °C, respectively. Steam bubble behavior, pressure oscillation amplitude and frequency were recorded and analyzed. Four typical regimes were found, namely, chugging, detached oscillatory, detached cracked and secondary bubble impinged regimes. A bubble condensation region map was developed by considering the effects of steam mass flux and water temperature. The average amplitude of pressure oscillation initially increased, and then decreased as water temperature increased. It reached its maximum value when water temperature was approximately 60–65 °C, which was the transition temperature range from the chugging regime to the detached oscillatory regime. Meanwhile, the frequency of pressure oscillation was within the range of 12–28 Hz. These values were higher than those for a vertical downward steam jet with the same steam mass flux and water temperature. A dimensionless correlation was obtained to predict the Strouhal number of pressure oscillation frequency. The predicted values corresponded well with the experimental data. The deviation was within the range of –9.12% to +8.30%.