Fig 2 - uploaded by Jože Kutin
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-The anti-symmetrical distribution of the Coriolis force on the beam-type measuring tube vibrating in the fundamental, symmetrical mode (j = 1)
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... reference [8], this method was applied to a straight and slender measuring tube clamped at both ends and vibrating in the fundamental, symmetrical mode of the Euler beam. Fig. 2 schematically shows the corresponding anti-symmetrical distribution of the Coriolis force at the moment when the tube is in its neutral position. The integral effect of the Coriolis force was reckoned as the twisting moment M cor acting around the middle of the tube ...
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... In addition to the rapidly rising pressure inside a CMF, researchers have also associated CMF error on the measurement of highly viscous flows to the distribution of the velocity field (Bobovnik et al., 2004;2005;Hemp, 2002;Kumar et al., 2010;Kutin et al., 2005;Kutin & Bajsić, 2001), while others contradicted that and argued that the uncertainties due to velocity profile/distribution on the meters' performance became negligible in the currently available CMFs (Bobovnik et al., 2004). ...
A Coriolis Mass Flowmeters (CMFs), outperform other flow measurement systems owing to their perceived high accuracy and good repeatability. That has attracted its use in different fields including the bunkering industry. Bunkering operations entail high viscosity flows that may limit the applicability of high accuracy CMFs. Furthermore, their performance for measurement of single-phase high viscosity flow remains less explored and the mechanisms responsible for possible additional measurement error due to high viscosity fluid are not thoroughly studied. This study characterizes the performance of CMFs on the measurement of high viscosity fluid via CFD simulations. It is observed that the error of CMFs on measurement of high viscosity is deemed relatively large at low mass flow rates and which monotonically increases as the viscosity increases. The sudden pressure increase and secondary flow in the vicinity of the flow sensors’ locations are the key factors influencing the measurement discrepancy. It is worthy to note that this study is highly significant to the bunkering industry as it can serve as a baseline for further experimental works on the measurement of bunker fuel oils.
... The former shows the derivation of the weight vector theory for Coriolis flowmeters, whereas the latter presents the calculation of the Coriolis flowmeter sensitivity if the effect of fluid viscosity is to be taken into account. More recent studies are published in [8], [9] and [10]. A review of the state-of-theart findings and open questions regarding velocity profile effects in Coriolis mass flowmeters is presented in [11]. ...
The weight vector theory for Coriolis flow meters has been the subject of research presented by Hemp and co-workers in various articles. The underlying theory may not be easily understood. This paper explains the application of the weight vector theory for Coriolis flowmeters. The theory is applied to simple theoretical meter configurations consisting of a single straight pipe. The application of the weight vector approach is of relevance when investigating velocity profile effects, e.g., in Coriolis flow meters. Promising results have been found in recent literature showing the vulnerability of straight pipe Coriolis flowmeter configurations to velocity profile effects. The application of the weight vector theory is shown to be either limited to the investigation of few parameters or employs unrealistic boundary conditions and lacks comparative studies, making a more comprehensive study desirable. The usefulness of the weight vector theory to predict velocity profile effects for bended tube is not apparent from today's state-of-the-art literature, but of great interest for flowmeter manufacturers since bended tubes designs are frequently used in today's Coriolis flowmeters.
... The negative values of w K for sensing distances s / L < 0.3 in the third mode (even if such positions of motion sensors may not be practical) show that the non-linearity at low Reynolds numbers does not always take the form of a decrease in flowmeter sensitivity. The optimum sensing positions, which could be defined on the basis of good sensitivity with satisfactory signal-to-noise ratio, are found to range from s / L = 0.4 to 0.7 [3]. Therefore velocity profile effects are expected to be larger for the higher modes (see Fig. 9). ...
The aim of this paper is to discuss velocity profile effects in Coriolis flowmeters and to review related research work. The measurements made by Coriolis flowmeters are dependent upon the steady flow velocity distribution within them whenever certain features of the fluid vibrational fields are not uniform inside the measuring tube. This dependence is confirmed by simulation results on two straight tube configurations, one operating in a beam-type mode and the other in a shell-type mode. Findings to date and open questions regarding velocity profile effects in Coriolis flowmeters are discussed for both fully developed and disturbed inlet flow conditions.
This paper starts from a brief revisit of key early published work so that an overview of modern Coriolis flowmeters can be provided based on a historical background. The paper, then, focuses on providing an updated review of Coriolis flow measurement technology over the past 20 years. Published research work and industrial Coriolis flowmeter design are both reviewed in details. It is the intention of this paper to provide a comprehensive review study of all important topics in the subject, which include interesting theoretical and experimental studies and innovative industrial developments and applications. The advances in fundamental understanding and technology development are clearly identified. Future directions in various areas together with some open questions are also outlined.
The compressibility of fluids in a Coriolis mass flowmeter can cause errors in the meter’s measurements of density and mass flow rate. These errors may be better described as errors due to the finite speed of sound in the fluid being metered, or due to the finite wavelength of sound at the operating frequency of the meter. In this paper, they are investigated theoretically and calculated to a first approximation (small degree of compressibility). The investigation is limited to straight beam-type (and does not consider shell-type) Coriolis meters. A lumped-parameter (coupled oscillator) model is used to explain the process causing the errors, and a simple 2-D continuum mechanics model is used to derive expressions for the magnitudes of the errors. Applications might be to Coriolis metering of gases, or to two-phase mixtures in the form of aerated liquids.
