Numerical Simulation Of Gas-liquid Two-phase Flow In Coriolis Flowmeter

Coriolis flowmeters can directly measure the mass flow of the fluid and have the advantages of high measurement accuracy,less sensitivity to temperature,density and flow conditions,and are widely used in various fields such as petroleum,natural gas,food and pharmaceutical industry.However,in industrial applications,gas-liquid two-phase flow often occurs.For example,liquefied natural gas is gasified to produce gas bubbles due to temperature increase.The gas-liquid two-phase flow is relatively complicated and there are relative velocities and interface effects between gas and liquid so that the gas-liquid two-phase flow is recognized as worldwide "non-measureable fluid".In the measurement of gas-liquid two-phase flow,the Coriolis flowmeter will bring some errors,so that it is necessary to conduct an in-depth study in this area and propose some compensation measures.In this paper,a fluid-solid coupling vibration analysis simulation method is proposed for the measurement of gas-liquid two-phase flow using the fluid-structure coupled finite element method.Under the given constraints,the numerical simulation of Coriolis flowmeters with different content and distribution of bubbles was carried out.The research progress and achievements are as follows:(1)Through the finite element simulation method,the vibration model of the measuring tube and the fluid is established.In order to simulate the bubble,a simulation method is proposed: a part of the units were selected from the established fluid model and their material property has been changed into gas.The property changed fluid units can be seen as “bubbles”.Through the finite element analysis method of fluid-structure coupled vibration,the phase difference of the model was calculated,which verified the feasibility of this method.(2)Aiming at the relatively low content of bubbles,mainly concentrated in less than 10%,the flow pattern in the pipeline mainly perform as bubbly flow.In this paper,a special tool was developed to build two-phase flow models.As a result,a large number of useful calculations has been got which provided technical supports for the development of new flowmeters.Parametric modeling of a gas-liquid two-phase flow improves the efficiency of model building and computation.