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

Xin Zhao and G. Lucas

School of Computing and Engineering University of Huddersfield, Huddersfield HD1 3DH, UK,

g.lucas@hud.ac.uk

ABSTRACT

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 dual­ sensor 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 Kelvin­ Helmholtz 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.

Keywords Dual­sensor probe array, high­speed dual plane ERT, Kelvin­Helmholtz wave