Transient and Frequency Response Characteristics of Two-Phase Condensing Flows: With and without Compressibility

In a tube-type condenser, involving complete condensation, small changes in the inlet vapor flowrate momentarily cause very large transient surges in the outlet liquid flowrate. Experimental data are presented which indicate that compressibility effects tend to attenuate the amplitude of these flow surges. The system mean void fraction model was extended to include compressibility effects and its predictions are shown to agree well with experimental data. The model is further extended to predict the response characteristics to an oscillatory inlet flowrate and compared with predictions based upon the drift-flux model.