The Effects of Forced Vibration on Two-Phase Flow in a Small Diameter Tube

The effects of forced vibrations on the motion of air-water two-phase mixture were studied in 2.4mm I.D. horizontal tube over rather wide range of flow conditions (about 60 flows for lateral vibration, 4 flows and 1 stagnant mixture for longitudinal vibration). 13 different modes of sinusoidal vibration with 1–8mm amplitude and 1–7.7 Hz frequency were exerted on the test tube. Pressure drop, void fraction and flow pattern of the two-phase flow were compared to those of the flow without forced vibration. It was made clear that the lateral vibration exerted on the tube induced a self exciting fluctuation of the pressure drop for a specific flow condition and longitudinal vibration on the tube promoted the bubble coalescence.