Reducing Phase Decoupling Errors of Coriolis Flowmeters for Slurry Flow Measurement Through Analytical Modelling

Phase decoupling is a main source of error that Coriolis flowmeters experience in slurry (liquid-solid) flow measurement. This study proposes an analytical model to estimate and mitigate this error for two-phase slurry flow measurement. The proposed model is developed based on the existing 'Bubble theory', where the most significant forces act on solid particles while flowing through a Coriolis tube are studied. Based on the force analysis a modified decoupling ratio equation is proposed. Extensive experimental tests were carried out on a slurry flow test loop to evaluate the performance of the proposed model for mass flowrates ranging from 5435 - 18582 kg/h and Solid Volume Fractions from 0 to 3.3%. In this study, two Coriolis flowmeters are tested on a horizontal pipe section with their measuring tubes in upward and downward orientations. The flowmeters are installed in these ways to examine the effect of flowmeter tube geometry and orientation conditions on slurry flow measurement. Negative errors (up to - 3.4 %) were observed under both orientations, which agree with the theoretical analysis of decoupled motions between solid and liquid phases. Experimental results revealed that the proposed analytical model yields a relative error within ± 1.1% and ± 1.3% for upward and downward installations of the two flowmeters, respectively, under all test conditions.