Numerical Study On Flow Characteristics Of Wet Gas Two Phase Flow In Orifice

As a special gas-liquid two-phase flow,wet gas widely exists in the field of oil and gas.With the development of oil and natural gas and the development of natural gas fields with high reserves,more and more attention is paid to the measurement of wet gas.When the wet gas two-phase flow through the orifice plate,due to the presence of a small amount of liquid phase,the pressure difference value is greater than when the same amount of gas phase flow alone,resulting in a“Over-Reading”phenomenon.Existing flow prediction Over-Reading models generally have two problems,on the one hand,the flow characteristics of wet gas in the orifice plate are still not fully understood;on the other hand,the applicability of these Over-Reading models under actual production high pressure conditions has not been verified.Computational fluid dynamics?CFD?methods can overcome the limitations of experimental conditions and make accurate predictions on the wet gas two-phase flow under a wider range of working conditions and a relatively short period of time.Therefore,this paper uses the CFD method to simulate the wet gas flow in the orifice plate using standard k-?model and discrete phase model in Fluent software.The simulation results are verified with the NEL experimental data,and it is found that the simulated Over-Reading value and the experimental Over-Reading value have the same change trend,and the relative error between the modified simulated Over-Reading value and the experimental Over-Reading value is between-4%and 1.5%,verifying the reliability of numerical simulation.Then,according to the simulation results,the flow field distribution,wall static pressure distribution and droplet concentration distribution of the two-phase flow of wet gas in the orifice plate were obtained,and it was found that the Over-Reading value increases with the increase of X_LMM parameter,decreases with the increase of pressure,and increases with the increase of the flow rate of gas.Finally,the simulation conditions were broadened to verify the applicability of the Over-Reading models for each measurement under high pressure,and it was found that when using the orifice plate to measure the flow of wet gas,the flow prediction Over-Reading models established for the Venturi tube performed poorly and was not applicable for the wet gas measurement in the orifice plate,and among the flow prediction Over-Reading models established for the orifice plate,the best performance is the Hall&Steven model?ISO model?.