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J. Kutin - One of the best experts on this subject based on the ideXlab platform.

  • numerical analysis of installation effects in Coriolis Flowmeters a case study of a short straight tube full bore design
    Flow Measurement and Instrumentation, 2013
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract A fully coupled, partitioned, numerical model that accounts for fluid–structure interaction is applied for a study of installation effects in a straight-tube Coriolis Flowmeter. Three flow disturbance elements positioned at different locations upstream of the measuring tube are considered in the study: a single elbow, closely coupled double elbows out-of-plane, and an orifice. The installation effects are estimated by comparing the mass-flow sensitivities obtained for the disturbed and the fully developed flow conditions in the measuring tube. The interpretation of the installation effects is given by analysing the anti-symmetric fluid forces in the measuring tube. The simulation results show that the magnitude of the installation effect in asymmetrically distorted flows varies for the different circumferential positions of the motion sensors. The sensitivity variations around the circumference of the measuring tube are less pronounced for measuring tubes with a higher circumferential stiffness.The predicted installation effects are also affected by changing the vibration direction of the tube with respect to the disturbance elements.

  • an improved three dimensional coupled fluid structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • An improved three-dimensional coupled fluid–structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • Estimation of velocity profile effects in the shell-type Coriolis Flowmeter using CFD simulations
    Flow Measurement and Instrumentation, 2005
    Co-Authors: G. Bobovnik, J. Kutin, Ivan Bajsić
    Abstract:

    Abstract This paper presents a study of the axisymmetric velocity profile effects in the shell-type Coriolis Flowmeter with a second circumferential mode, which exploits the results of computational fluid dynamics simulations. Simulations were carried out for viscous fluid flow in the vibrating measuring tube, whose mode shape remained fixed during the transient simulation process. We observed time responses of the integral anti-symmetric fluid forces acting on the inner wall of the measuring tube. Their magnitudes and their relative variations with the mass flow rate of the fluid were used for the integral estimation of the velocity profile effect. Simulation results are presented for different fluid velocities through the measuring tube and show considerable loss of Flowmeter’s sensitivity in the range of lower Reynolds numbers. The results are also compared with the weight vector estimations of the velocity profile effect and are evaluated for two different turbulent models.

  • Coupled finite-volume/finite-element modelling of the straight-tube Coriolis Flowmeter
    Journal of Fluids and Structures, 2005
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract A coupled finite-volume (FV)/finite-element (FE) numerical model of the straight-tube Coriolis Flowmeter is considered. It uses the staggered partitioned algorithm with additional pressure predictor and interfield iterations to minimize the time lag in the fluid–structure coupling procedure. The solutions were evaluated in terms of the fundamental natural frequency of the vibrating system and the corresponding phase difference between the motion of the symmetrically located sensing points on the measuring tube, which are actually exploited as the measuring effects of the Coriolis Flowmeter for the fluid density and the mass flowrate, respectively. The FV/FE numerical model was validated by comparison with the solutions of the Euler beam and one-dimensional flow model, as well as with the solutions of the Flugge shell and potential flow model. The respective simulations were performed for different lengths of the measuring tube.

G. Bobovnik - One of the best experts on this subject based on the ideXlab platform.

  • numerical analysis of installation effects in Coriolis Flowmeters a case study of a short straight tube full bore design
    Flow Measurement and Instrumentation, 2013
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract A fully coupled, partitioned, numerical model that accounts for fluid–structure interaction is applied for a study of installation effects in a straight-tube Coriolis Flowmeter. Three flow disturbance elements positioned at different locations upstream of the measuring tube are considered in the study: a single elbow, closely coupled double elbows out-of-plane, and an orifice. The installation effects are estimated by comparing the mass-flow sensitivities obtained for the disturbed and the fully developed flow conditions in the measuring tube. The interpretation of the installation effects is given by analysing the anti-symmetric fluid forces in the measuring tube. The simulation results show that the magnitude of the installation effect in asymmetrically distorted flows varies for the different circumferential positions of the motion sensors. The sensitivity variations around the circumference of the measuring tube are less pronounced for measuring tubes with a higher circumferential stiffness.The predicted installation effects are also affected by changing the vibration direction of the tube with respect to the disturbance elements.

  • an improved three dimensional coupled fluid structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • An improved three-dimensional coupled fluid–structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • Estimation of velocity profile effects in the shell-type Coriolis Flowmeter using CFD simulations
    Flow Measurement and Instrumentation, 2005
    Co-Authors: G. Bobovnik, J. Kutin, Ivan Bajsić
    Abstract:

    Abstract This paper presents a study of the axisymmetric velocity profile effects in the shell-type Coriolis Flowmeter with a second circumferential mode, which exploits the results of computational fluid dynamics simulations. Simulations were carried out for viscous fluid flow in the vibrating measuring tube, whose mode shape remained fixed during the transient simulation process. We observed time responses of the integral anti-symmetric fluid forces acting on the inner wall of the measuring tube. Their magnitudes and their relative variations with the mass flow rate of the fluid were used for the integral estimation of the velocity profile effect. Simulation results are presented for different fluid velocities through the measuring tube and show considerable loss of Flowmeter’s sensitivity in the range of lower Reynolds numbers. The results are also compared with the weight vector estimations of the velocity profile effect and are evaluated for two different turbulent models.

  • Coupled finite-volume/finite-element modelling of the straight-tube Coriolis Flowmeter
    Journal of Fluids and Structures, 2005
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract A coupled finite-volume (FV)/finite-element (FE) numerical model of the straight-tube Coriolis Flowmeter is considered. It uses the staggered partitioned algorithm with additional pressure predictor and interfield iterations to minimize the time lag in the fluid–structure coupling procedure. The solutions were evaluated in terms of the fundamental natural frequency of the vibrating system and the corresponding phase difference between the motion of the symmetrically located sensing points on the measuring tube, which are actually exploited as the measuring effects of the Coriolis Flowmeter for the fluid density and the mass flowrate, respectively. The FV/FE numerical model was validated by comparison with the solutions of the Euler beam and one-dimensional flow model, as well as with the solutions of the Flugge shell and potential flow model. The respective simulations were performed for different lengths of the measuring tube.

I Bajsic - One of the best experts on this subject based on the ideXlab platform.

  • numerical analysis of installation effects in Coriolis Flowmeters a case study of a short straight tube full bore design
    Flow Measurement and Instrumentation, 2013
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract A fully coupled, partitioned, numerical model that accounts for fluid–structure interaction is applied for a study of installation effects in a straight-tube Coriolis Flowmeter. Three flow disturbance elements positioned at different locations upstream of the measuring tube are considered in the study: a single elbow, closely coupled double elbows out-of-plane, and an orifice. The installation effects are estimated by comparing the mass-flow sensitivities obtained for the disturbed and the fully developed flow conditions in the measuring tube. The interpretation of the installation effects is given by analysing the anti-symmetric fluid forces in the measuring tube. The simulation results show that the magnitude of the installation effect in asymmetrically distorted flows varies for the different circumferential positions of the motion sensors. The sensitivity variations around the circumference of the measuring tube are less pronounced for measuring tubes with a higher circumferential stiffness.The predicted installation effects are also affected by changing the vibration direction of the tube with respect to the disturbance elements.

  • an improved three dimensional coupled fluid structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • coupled finite volume finite element modelling of the straight tube Coriolis Flowmeter
    Journal of Fluids and Structures, 2005
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, I Bajsic
    Abstract:

    Abstract A coupled finite-volume (FV)/finite-element (FE) numerical model of the straight-tube Coriolis Flowmeter is considered. It uses the staggered partitioned algorithm with additional pressure predictor and interfield iterations to minimize the time lag in the fluid–structure coupling procedure. The solutions were evaluated in terms of the fundamental natural frequency of the vibrating system and the corresponding phase difference between the motion of the symmetrically located sensing points on the measuring tube, which are actually exploited as the measuring effects of the Coriolis Flowmeter for the fluid density and the mass flowrate, respectively. The FV/FE numerical model was validated by comparison with the solutions of the Euler beam and one-dimensional flow model, as well as with the solutions of the Flugge shell and potential flow model. The respective simulations were performed for different lengths of the measuring tube.

  • the effect of flow conditions on the sensitivity of the Coriolis Flowmeter
    Flow Measurement and Instrumentation, 2004
    Co-Authors: G. Bobovnik, J. Kutin, I Bajsic
    Abstract:

    Abstract The aim of this paper is to investigate the effect of flow conditions on a Coriolis Flowmeter that has a straight and slender measuring tube. The CFD analysis was performed for fully developed, asymmetric triangular and swirl flows introduced at the inlet. The asymmetry and swirl numbers were used to evaluate the resulting velocity field in the measuring tube. In addition, the influence of different inlet-flow conditions on the sensitivity of the Flowmeter was estimated, using the value of the moment that causes the deflection of the tube’s first mode shape. The results are presented for a variety of different Reynolds numbers, two frequencies of vibration and three different dimensions of the measuring tube.

Tao Wang - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigations into the transient behaviours of CO2 in a horizontal pipeline during flexible CCS operations
    International Journal of Greenhouse Gas Control, 2018
    Co-Authors: Wenbiao Zhang, Ding Shao, Yong Yan, Shi Liu, Tao Wang
    Abstract:

    Abstract Power plants with CCS facilities should be operated flexibly because of the variability in electricity demand. Load change, start-up and shutdown will occur during flexible CCS operations. It is necessary to investigate the transient behaviours of CO2 flow in the pipeline during these operations for optimized operation of CCS plants. However, very limited experimental data for gas-liquid two-phase CO2 under CCS conditions are available. As a result, experimental observations of the CO2 transient behaviours were conducted on a CO2 gas-liquid two-phase flow rig. Load change, start-up and shutdown of a CO2 flow process were replicated on the rig. Coriolis Flowmeters and high-speed imaging equipment were used to observe the mass flow rate, thermophysical properties and flow regimes of the CO2 flow. There are significant discrepancies in the mass flow rate of two-phase CO2 between the test value and the reference value during the load change. During the start-up operation, the flow regime transits from liquid slug flow to gas bubbly flow and the mass flow rate from the Coriolis Flowmeter presents two-step changes. In addition, the depressurization and evaporation of liquid CO2 in the pipeline were observed during the shutdown operation.

  • I2MTC - Gas-liquid two-phase flow measurement using Coriolis Flowmeters incorporating neural networks
    2016 IEEE International Instrumentation and Measurement Technology Conference Proceedings, 2016
    Co-Authors: Lijuan Wang, Yong Yan, Jinyu Liu, Xue Wang, Tao Wang
    Abstract:

    Coriolis Flowmeters are commonly used to measure single phase flow. In recent years attempts are being made to apply Coriolis Flowmeters to measure two-phase flows. This paper presents a neural network based approach that has been applied to Coriolis Flowmeters to measure both the liquid flow rate and the gas volume fraction of a two-phase flow. Experimental tests were conducted on a purpose-built two-phase flow test rig on both horizontal and vertical pipelines. The mass flow rate ranges from 700 kg/h to 14500 kg/h whilst the gas volume fraction is between 0 and 30%. A set of variables, including observed density, apparent mass flow, differential pressure across the Coriolis Flowmeter and signals to maintain flow tube oscillation, are considered as inputs to a neural network. Two neural networks are established through training with experimental data obtained from the flow rig on horizontal and vertical pipelines, respectively. The performance of both neural networks is assessed in comparison with the reference readings. Experimental results suggest that the relative errors of the corrected mass flow rate of liquid for the vertical and horizontal installations are no greater than ±1.5% and ±2.5%, respectively. The gas volume fraction is predicted with relative errors of less than ±10% and ±20%, respectively, for vertical and horizontal installations in most cases.

  • DEVELOPMENT OF NUCLEAR-SPECIFIC Coriolis FlowmeterS BASED ON THE STRAIGHT-TUBE TECHNOLOGY
    2015
    Co-Authors: Tao Wang, Yousif Hussain
    Abstract:

    The application of Coriolis Flowmeters to various industries has been expanding since they were successfully introduced in the market some 30 years ago. This paper specifically reports the development of Coriolis Flowmeters for the nuclear industry based on the latest straight-tube technology. An advanced numerical method combining the strength of commercially available simulation packages and in-house theoretical work was used in the development. This includes the initial prediction of flow sensitivity using the fluid-structure interaction theory for straight flow tubes to ensure sufficient measurement accuracy under various process conditions. It also includes further detailed analysis of the entire Flowmeter to make sure its natural frequencies away from the seismic frequency range due to nuclear application safety reasons. Furthermore, a new calibration and testing procedure is reported in this paper, which includes the normal calibration condition and also simulates possible process conditions during the nuclear applications (e.g. varying fluid temperature). Additionally, calculations based on the Design by Formula approach according to the governing codes, particularly ASME Boiler and Pressure Vessel Code, Section III, are also reported. These simplified calculations are of significant importance for Coriolis Flowmeters to be applied to nuclear applications. Finally, a case study which involved significant collaboration with a well-known safety-related solution provider in the nuclear industry is described, where Coriolis Flowmeters were required to provide accurate measurement for the boric acid make-up subsystem in a pressurised water reactor system. Design checks and special considerations for the fabrication and testing according to the rules of ASME Code Section III together with a quality assurance procedure as described in the case study showed that the developed Coriolis Flowmeter can meet the specific requirements of nuclear applications in terms of both measurement performance and safety concerns. 1

  • Coriolis Flowmeters a review of developments over the past 20 years and an assessment of the state of the art and likely future directions
    Flow Measurement and Instrumentation, 2014
    Co-Authors: Tao Wang, Roger C. Baker
    Abstract:

    Abstract 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.

  • Development of Nuclear-Specific Coriolis Flowmeters Based on the Straight-Tube Technology
    18th International Conference on Nuclear Engineering: Volume 1, 2010
    Co-Authors: Tao Wang, Yousif Hussain
    Abstract:

    The application of Coriolis Flowmeters to various industries has been expanding since they were successfully introduced in the market some 30 years ago. This paper specifically reports the development of Coriolis Flowmeters for the nuclear industry based on the latest straight-tube technology. An advanced numerical method combining the strength of commercially available simulation packages and in-house theoretical work was used in the development. This includes the initial prediction of flow sensitivity using the fluid-structure interaction theory for straight flow tubes to ensure sufficient measurement accuracy under various process conditions. It also includes further detailed analysis of the entire Flowmeter to make sure its natural frequencies away from the seismic frequency range due to nuclear application safety reasons. Furthermore, a new calibration and testing procedure is reported in this paper, which includes the normal calibration condition and also simulates possible process conditions during the nuclear applications (e.g. varying fluid temperature). Additionally, calculations based on the Design by Formula approach according to the governing codes, particularly ASME Boiler and Pressure Vessel Code, Section III, are also reported. These simplified calculations are of significant importance for Coriolis Flowmeters to be applied to nuclear applications. Finally, a case study which involved significant collaboration with a well-known safety-related solution provider in the nuclear industry is described, where Coriolis Flowmeters were required to provide accurate measurement for the boric acid make-up subsystem in a pressurised water reactor system. Design checks and special considerations for the fabrication and testing according to the rules of ASME Code Section III together with a quality assurance procedure as described in the case study showed that the developed Coriolis Flowmeter can meet the specific requirements of nuclear applications in terms of both measurement performance and safety concerns.Copyright © 2010 by ASME

Ivan Bajsić - One of the best experts on this subject based on the ideXlab platform.

  • THE EFFECT OF DIFFERENT INLET- VELOCITY PROFILES ON THE PERFORMANCE OF A Coriolis Flowmeter
    2015
    Co-Authors: Gregor Bobovnik, Jože Kutin, Ivan Bajsić
    Abstract:

    Abstract − Numerical simulations (using finite volume method) of the flow of a viscous fluid through a measuring tube were performed to identify the effects of different inlet-flow conditions on the performance of a straight, slender-tube, Coriolis Flowmeter. The magnitudes of the anti-symmetric fluid forces and the twisting moments acting on the measuring tube were compared with results from a one-dimensional fluid-flow model. Simulations were made for some hypothetical inlet-velocity profiles that represent extreme cases of various Flowmeters ’ installation positions and flow regimes in a pipeline. No significant effects of the modelled inlet-velocity profiles on the performance of the Flowmeter were observed

  • An improved three-dimensional coupled fluid–structure model for Coriolis Flowmeters
    Journal of Fluids and Structures, 2008
    Co-Authors: Nikolaj Mole, G. Bobovnik, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract The paper presents a coupled numerical model built to simulate the operation of Coriolis Flowmeters, which exploit the alteration of the vibration mode shape of the measuring tube for the mass flow rate measurement. The explained measuring effect is a consequence of the interaction between the motion of the tube, vibrating at its natural frequency, and the fluid flow in it. The numerical model is realized by coupling of a finite volume (FV) code for fluid flow analysis with a finite element (FE) code for structural analysis using the conventional staggered solution procedure, with added inner iterations to achieve strong coupling. The simulation algorithm is divided into two steps. A free vibration of the measuring tube considered in the first step is complemented in the second step, after the numerical free vibration response is properly stabilized, with the harmonic excitation force actuating the measuring tube at its resonant frequency of several hundreds of Hertz to resemble the operation of actual Coriolis Flowmeters. Different scenarios using zero-order or three-point fluid load predictor and soft application of the fluid load in the initial stages of the simulation are compared to yield a simulation strategy, which will minimize the time needed to obtain the stabilized steady-state response of the vibrating measuring tube. The proposed simulation procedure was applied on a straight-tube Coriolis Flowmeter and used for the estimation of the velocity profile effect. The results exhibit sufficient stability (low scatter) to be used for the estimation of sensitivity variations of order of magnitude around tenths of a percent.

  • Estimation of velocity profile effects in the shell-type Coriolis Flowmeter using CFD simulations
    Flow Measurement and Instrumentation, 2005
    Co-Authors: G. Bobovnik, J. Kutin, Ivan Bajsić
    Abstract:

    Abstract This paper presents a study of the axisymmetric velocity profile effects in the shell-type Coriolis Flowmeter with a second circumferential mode, which exploits the results of computational fluid dynamics simulations. Simulations were carried out for viscous fluid flow in the vibrating measuring tube, whose mode shape remained fixed during the transient simulation process. We observed time responses of the integral anti-symmetric fluid forces acting on the inner wall of the measuring tube. Their magnitudes and their relative variations with the mass flow rate of the fluid were used for the integral estimation of the velocity profile effect. Simulation results are presented for different fluid velocities through the measuring tube and show considerable loss of Flowmeter’s sensitivity in the range of lower Reynolds numbers. The results are also compared with the weight vector estimations of the velocity profile effect and are evaluated for two different turbulent models.

  • Coupled finite-volume/finite-element modelling of the straight-tube Coriolis Flowmeter
    Journal of Fluids and Structures, 2005
    Co-Authors: G. Bobovnik, Nikolaj Mole, J. Kutin, Boris Štok, Ivan Bajsić
    Abstract:

    Abstract A coupled finite-volume (FV)/finite-element (FE) numerical model of the straight-tube Coriolis Flowmeter is considered. It uses the staggered partitioned algorithm with additional pressure predictor and interfield iterations to minimize the time lag in the fluid–structure coupling procedure. The solutions were evaluated in terms of the fundamental natural frequency of the vibrating system and the corresponding phase difference between the motion of the symmetrically located sensing points on the measuring tube, which are actually exploited as the measuring effects of the Coriolis Flowmeter for the fluid density and the mass flowrate, respectively. The FV/FE numerical model was validated by comparison with the solutions of the Euler beam and one-dimensional flow model, as well as with the solutions of the Flugge shell and potential flow model. The respective simulations were performed for different lengths of the measuring tube.

  • Characteristics of the shell-type Coriolis Flowmeter
    Journal of Sound and Vibration, 1999
    Co-Authors: J. Kutin, Ivan Bajsić
    Abstract:

    Abstract The primary element of the Coriolis Flowmeter is a measuring tube conveying fluid. While the tube in the classical meter undergoes a beam-type vibration, the shell-type tube vibrates in the second circumferential mode. This paper analyzes theoretical characteristics of the straight-tube shell-type Coriolis meter. A mathematical model founded on the theory of Flugge thin shell and linearized potential flow was used. The results show the similarity between measuring principles in the shell-type and the beam-type meter. Finally, we carried out a comparison with the straight-tube beam-type meter, based on the condition that both meters have the same pressure loss. It was found that the shell-type meter has a higher working frequency and a larger phase shift due to flow.