Measurement of the homogeneous velocity of inclined oil-in-water flows using a resistance cross correlation flow meter

This paper describes an investigation into a cross correlation flow meter, using 'global' resistance sensors, for measuring the homogeneous velocity of inclined oil-in-water flows. The cross correlation flow meter measures the axial propagation speed U-cc of intermittent Kelvin-Helmholtz structures in the flow. It is shown that, for inclination angles in the range 15 degrees to 45 degrees from the vertical, the measured velocity U-cc is dependent only upon the homogeneous velocity and is independent both of the inclination angle theta of the flow and of the oil volume fraction alpha. For an angle of inclination to the vertical of 60 degrees, U-cc is dependent both upon the homogeneous velocity and upon the oil volume fraction alpha. For inclination angles in the range 15 degrees less than or equal to theta less than or equal to 45 degrees predictions of the homogeneous velocity were obtained using only the measured cross correlation velocity U-cc. For 15 degrees less than or equal to theta less than or equal to 45 degrees, the mean percentage error (E) over bar in the predicted homogeneous velocity was 0.1% whilst the standard deviation (S) over bar of the percentage error in the predicted values of the homogeneous velocity was found to be 4.0%. For the angle of inclination to the vertical of 60 degrees predictions of the homogeneous velocity were obtained using the measured cross correlation velocity U-cc and the measured oil volume fraction alpha. For theta = 60 degrees the mean percentage error (E) over bar in the predicted homogeneous velocity was -0.39% whilst the standard deviation (S) over bar of the percentage error in the predicted values of the homogeneous velocity was 5.2%.