Manufacturing variation of the measuring tube in a Coriolis flowmeter

To achieve an increase in robust design for Coriolis flowmeters a numerical model is developed. This uses finite-element (FE) methods and starts from direct-coupled fluid-tube equations of motion using a Timoshenko beam element with two nodes and six degrees of freedom for each node. It is solved using ANSYS MATRIX27 elements. The FE solution is compared with analytical solutions and found to be in good agreement for low flow rates, but for higher flow rates the assumption of small fluid velocity in the analytical solution is thought to account for the discrepancy found. Good agreement is also obtained when the behaviour of the FE models is compared with published findings on prestressed beams. The model is then used for examining effects of manufacturing variation. Key characteristics are identified for the measuring tube, and improved robustness is observed due to tensile prestressing. Further work is required to improve robustness to operating conditions.