Flow Velocity Distribution Towards Flowmeter Accuracy: CFD, UDV, and Field Tests

Abstract

Inconsistences regarding flow measurements in real hydraulic circuits have been detected. Intensive studies stated that these errors are mostly associated to flowmeters, and the low accuracy is connected to the perturbations induced by the system layout. In order to verify the source of this problem, and assess the hypotheses drawn by operator experts, a computational fluid dynamics (CFD) model, COMSOL Multiphysics 4.3.b, was used. To validate the results provided by the numerical model, intensive experimental campaigns were developed using ultrasonic Doppler velocimetry (UDV) as calibration, and a pumping station was simulated using as boundary conditions the values measured in situ. After calibrated and validated, a new layout/geometry was proposed in order to mitigate the observed perturbations.Hence, this research has the objective to analyze different variables, namely the pipe layout and the way it can disturb the flow and flowmeter accuracy. The purpose is to assess how vertical or horizontal curves, expansions and reductions, among other geometries can influence the flow and, consequently the measurements. To fulfil this goal, the influence of several perturbations were identified, using an electromagnetic flowmeter and ultrasonic Doppler velocimetry (UDV), and compared with the computed velocity profiles, using CFD models. The numerical model was calibrated and validated using the same conditions as the experimental facility. The numerical simulations showed good approximation with the velocity measurements for two different geometries. To evaluate the accuracy of the numerical results, several experimental tests, using two different geometries, were firstly developed, identifying perturbations in the flow measurements, followed by analysis in a real case study. Electromagnetic FlowmetersFlowmeters are one of the most important and used devices to measure accurately, the volume flow rate [6]. Nowadays there are several types of flowmeters, but the most important for flow measurement are the electromagnetic and the ultrasonic ones. They are characterized for their high accuracy and self-monitoring [7]. According to the authors of [1], electromagnetic flowmeters are only disturbed by existing particles that may change the magnetic properties of each fluid. Properties like temperature, viscosity and the fluid density do not affect the measurements. However, as mentioned in [8], a steady regime is a necessary condition to guarantee accurate measurements.These flowmeters have two different elements: the primary and the convertor (Figure 1). The first element corresponds to a hollow circular pipe with coils along its length and is set in the pipeline [9,10]. The flow passing through the section, creates an electromagnetic field which is proportional to the volume flow rate. The convertor is the brain element: it creates a magnetic field, reads the voltage, displays the data, and generates outputs. The convertor displays the volume flow rate and the amount of volume passed through.Water 2018, 10, x FOR PEER REV...

Prediction of Flow Velocity from the Flexural Vibration of a Fluid-Conveying Pipe Using the Transfer Function Method

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Transient-Flow Induced Compressed Air Energy Storage (TI-CAES) System towards New Energy Concept

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Rheological Characterization of Non-Newtonian Mixtures by Pressure Pipe Tests

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