Effects of liquid viscosity on liquid film flow in gas-liquid two-phase annular flow

In order to clarify the effects of liquid viscosity on liquid flow characteristics in gas-liquid two-phase flow, measurements of interfacial structure were carried out. Water and glycerol solutions were employed to vary the liquid viscosity and the range of kinematic viscosity of liquid was 1-70 cSt. The interfacial structure was measured by 5 ring-type conductance probes arranged axially with a gap of 32 mm, and the probes could provide the information of time-varying behavior of gas-liquid interface. Time-series traces of liquid film thickness drawn using the liquid film thickness signals detected by the five probes were presented and it was clarified that the onset of disturbance waves occurred at R-eL= 200. Applying the turbulent velocity profile of single phase flow to the two-phase annular flow, the onset condition was found to be shown as the non-dimensional distance from the wall, y(+)=6.5. Typical calculation models of void fraction were examined to the present data. Lockhart Martinelli model and Drift flux model are clarified to give qualitatively good results in the effects of liquid viscosity.