Oil-water two-phase flow velocity measurement with Continuous wave ultrasonic Doppler

Abstract

Oil-water two-phase flow exists widely in many industries. Accurate measurement of flow velocity is of significance for quantify the volume or mass flow rate as well as monitor the operation safety. A non-intrusive one-side Continuous Wave Ultrasonic Doppler (CWUD) sensor is presented for measuring the overall superficial velocity of oil-water two-phase flow. The one-side CWUD sensor consists of two-chip transducer with resonant frequency of 1MHz, both of which are installed at the bottom of test pipe, and the sample volume cover the whole radial direction of pipe cross-section. The Doppler shift signal collected by ultrasonic sensor is directly related to the average velocity of dispersed phase within the sample volume of CWUD. The overall superficial flow velocity is derived by a linear correction of measured average velocity, based on the analysis of average Doppler shift properties in different flow conditions, i.e. water continuous flow and oil continuous flow. Dynamic experiments were conducted at a horizontal oil-water two-phase flow loop. It can be found that the average Doppler shift within the sample volume increases with overall superficial flow velocity, however, varies with different continuous phases at the same overall superficial flow velocity. The results show that the mean relative error of overall superficial flow velocity is 3.45%.