Two-Phase Pressure Drop Across Abrupt Area Changes in Oscillatory Flow

The ability of one-dimensional momentum balances to predict behavior during two-phase oscillatory flow has been examined. Flow oscillations in a Freon-Freon vapor system were induced by cycling a three-way valve so as to divert a varying portion of the total flow from the test section. The data taken included the phase shift between the pressure and flow curves and the head fluctuation to flow fluctuation ratio. These data were compared with theoretical predictions obtained via the impedance method. Although some discrepancies between predictions and measurements were observed, the discrepancies were generally within the range of error associated with the measurement and analysis techniques used.