The Investigation of Gas Distribution Asymmetry Effect on Coriolis Flowmeter Accuracy at Multiphase Metering

Abstract

Multiphase flows are encountered in various industries, and the Coriolis flowmeter (CFM) is considered a high potential flowmeter for the metering of these flows. However, the decoupling effect and asymmetrical gas distribution in a CFM might decrease the accuracy of its multiphase flow metering The asymmetry of gas distribution in a CFM and its influence on the metering accuracy have only been qualitatively investigated in a few studies. The present paper quantitatively describes the gas distribution asymmetry in several CFMs under different flow conditions by numerical simulation. The simulation methodology is developed and validated by a results comparison with a conducted experiment and published data for bubbly, stratified and transitional flow regimes. U-shaped and triangle-shaped CFMs of different diameters are investigated at different gas volume fractions and flow rates. It is shown that the increase in the gas volume fraction and the reduction in the mixture flow rate lead to the increase in the gas distribution asymmetry. The strong correlation between the gas distribution asymmetry and the experimentally observed CFM error is demonstrated. The correction of the CFM error is proposed based on this correlation allowing the metering error to be decreased from 34% to 10% for the investigated conditions.

Effect of Weld Shape on Temperature Field of Nozzle Flowmeter

“…Enz [13] investigated the effect of asymmetric actuator and detector positions on the Coriolis flowmeter and measured phase shifts, and they found that both force and detector position asymmetries would lead to measurement errors. Shavrina et al [14] numerically studied the Coriolis flowmeter under various models with different gas volume fractions and flow conditions and verified it with experimental results. The study showed that the gas distribution asymmetry increased with increasing gas volume fraction and decreasing mixing flow rate and that the error of the Coriolis flowmeter was mainly caused by the asymmetry of the gas distribution.…”

“…Based on the static pressure difference, the nozzle flowmeter has the ability to detect the flow rate [1]. At present, many researchers [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] have studied the internal flows and external characteristics of various types of flowmeters under different conditions from different aspects, and some researchers [21][22][23][24][25] have designed more suitable new flowmeters because of the limitations of the operating environment and the shortcomings of existing flowmeters.…”

A Pressure-Based Multiphase Flowmeter: Proof of Concept

“…Measurement Principle for Mixture Density [6][7][8] Differential pressure across area reduction Gamma-ray attenuation [11] Coriolis (vibrating tubes): deformation Coriolis (vibrating tubes): natural frequency [12] Pipe strain (cross correlation): flow velocity Pipe strain (cross correlation): sound speed [13] Gas-liquid cyclonic separator, with a Coriolis meter in the liquid line and an orifice plate in the gas line…”

“…The gamma-ray technique ( [6][7][8]) uses nuclear sources which have safety concerns and logistical hassles. A Coriolis meter may underperform at high gas fractions (above 20%), particularly with respect to measuring density, due to the phenomenon of gas-liquid decoupling [11]. Strain-sensor arrays may underperform at medium gas fractions (in the 20-80% range) due to a fundamentally weak relationship between the sound speed and fluid density [12].…”

“…For measuring mixture density, gamma-ray attenuation is one of the most prevalent techniques in oil-and-gas applications ( [6][7][8]). Another well-known technique for measuring the total mass flow rate is the Coriolis-force-induced deformation/twisting of a vibrating flow tube [11]. A 'Coriolis meter' can additionally measure fluid density based on the natural frequency of tube vibration.…”