The simulation of Coriolis meter response to pulsating flow using a general purpose FE code

The publication of a theoretical analysis of the response of a simple strai ght-tube Coriolis meter to flow pulsations raised the question of the exten t to which the results of that analysis are generic over the wide range of geometric configurations used in commercially available meters. A procedure for using a general purpose finite element (FE) code to investigate this q uestion is presented. The dual time scales, which are an essential feature of pulsating how through a Coriolis meter, are used to minimize the amount of computation required to simulate the meter response. The FE model is dev eloped in a full 3-D form with shear deflection and axial forces, and the c omputation of the simulated response for the geometrically most complex met er currently available shows that this level of representation is necessary to reveal the full details of the response. The response derived from the FE simulation for straight-tube meters, is compared with the published theo retical response and to experimental data. Over a range of different meters , the characteristics of the sensor signals in the presence of flow pulsati ons are shown to be generally similar. In all cases, the simulated sensor s ignals contain components corresponding to beating between the pulsation fr equency and the meter drive frequency, in addition to the main component at the drive frequency. Spectra are computed from the simulated meter respons es and these are used to show that the relationship between the mass flow r ate and the phase difference between the component of the sensor signals at the drive frequency, is not significantly affected by the pulsations. Thus , the work suggests that the reports of changes in meter calibration due to certain frequencies of flow pulsation represent errors in signal processin g rather than fundamental changes in the meter characteristics. (C) 2000 Ac ademic Press.