A CLAMP-ON ULTRASOUND CROSS-CORRELATION FLOWMETER FOR LIQUID-SOLID 2-PHASE FLOW MEASUREMENT

A clamp-on pulsed ultrasound cross-correlation flowmeter has been developed by the authors which can measure the mixture velocity of liquid/solid two-phase flows. Small, well-dispersed solids exist in the calibration and test liquids, which for a given mixture have consistent slip. Allowance for this slip in determining mixture velocity is made by the meter factor obtained during specific calibrations. The flowmeter has been calibrated in a horizontal pipe by comparison with an electromagnetic flowmeter using a well-mixed, low concentration paper pulp (concentration 0.4% by weight, average solids density approximately 1100 kg m-3) as the measured medium. The maximum deviation between these two meters is +/-4.8% with a confidence level of 99.73%. One prototype of this flowmeter was installed on a pulp pipeline at a paper mill for long-term reliability trails. The results are encouraging. A second prototype was installed in series with an oval gear volumetric flowmeter on a pipeline, in which very high viscosity crude oil flowed. Results show that the cross-correlation flowmeter worked reliably even at velocities less than 0.3 m s-1; the maximum difference between the two types of meter was less than +/-3%.