Characterisation of the mean and time dependent properties of inclined oilinwater pipe flows using dualsensor probes

An array of dualsensor conductance probes, which contains a number of dualsensor probes equispaced across the diameter of an 80mm pipe, is introduced in this paper for characterizing bubbly oilinwater pipe flows inclined at angles from 15 degrees to 60 degrees to the vertical. Each dualsensor probe measures the local axial oil velocity and the local oil volume fraction at the position of the probe. Choosing an averaging interval of 0.05s, values of local oil volume fraction and local oil velocity were measured simultaneously at the different probe positions, enabling the time dependent structure of the two phase flow to be investigated. After data processing, time dependent variations of volume fraction along the pipe were found which are consistent with the presence of intermittent KelvinHelmholtz wave structures in the flow. A high speed dualplane ERT system was used to measure the axial propagation speed of these KelvinHelmholtz waves, using crosscorrelation. This paper presents results for the measured characteristics of inclined oilinwater flows including (i) time averaged and time dependent oil volume fraction and velocity distributions and (ii) the KelvinHelmholtz wave properties including the wave speed, wave amplitude, wavelength and wave frequency.