| Two-phase flow widely exist in industrial production.With the requirement of industrial development and management optimization,it is urgent to develop an on-line metering device with high precision instead of the traditional metering device.Based on the two-phase flow pressure drop characteristic of throttle device,this article mainly uses the method of FLUNT numerical simulation combined with laboratorial experiment to study gas-liquid two phase flow throttling characteristics of venturi nozzles.According to the reseach results,two measurement methods gas-liquid two phase flow throttling characteristics of venturi nozzles and double throttle measurement were proposed to measure two-phase flow without two phase flow separation.The Mixture model was established to simulate the flow characteristics of gas liquid two phase flow through the Venturi nozzles.Comparison of pressure drop between two phase flow and single-phase flows through the nozzles.The difference of pressure drop when the composition of two phase flow is different.The Changes of the flow rate and flow pattern distribution of two phase flow.The simulation experiment results show that the pressure drop of two phase flow is larger than single phase flow when it flows through the nozzle.The pressure drop of two phase flow flowing through the nozzle gets bigger when the flow rate of one phase is increased and the other one is fixed.Smaller the throttle ratio is,more obvious the pressure drop will be.A surge in speed appeared when two phase flow through the throat of nozzles.The velocity of two phase flow increases outside-in at the throat of Venturi nozzle.Greater two phase flow velocity is,more uniform the velocity distribution will be.Throat diameter d=12.2mm and d=7.26mm venturi nozzles are developed to carry out experiment on the multiphase experimental loop.The flow characteristics of stratified flow,wave flow,slug flow and annular flow when they through Venturi nozzles.The diameter of the pipeline is 40mm,and the experimental media are air and water.This article analyzes the influence factors of?is studied when two phase flow flows through Venturi nozzle.The results show that?relates to,Fr_g,pressure and throttle ratio?.Pressure drop formula of two phase flow flowing through venturi nozzle is set up.Compared with classic venturi pressure drop formula,the minimum root-mean-square error of formula in this article is 0.103.The relationship between two phase flow pressure fluctuation and the dryness of two phase flow is studied by experiments.In this paper,a two phase flow measurement method is proposed and the method is based on two phase flow pressure difference and differential pressure fluctuation signal of gas-liquid two-phase flow.The error of gas mass flow rate is about±9%.The liquid mass flow error is about±7%.The experiment of two phase flow through double throttling element is carried out.The measurement accuracy is improved by the continuous iterative method of two section flow device.The error of gas phase mass flow measurement is about±10%,and the error of liquid phase mass flow rate is about±9%.Compared with other measurement methods,Venturi nozzles have simple structure,low in cost and convenient to use.To establish a more accurate pressure drop-flow correlation by optimizing the structure of the nozzle.It is expected to improve accuracy of the measure-ment,then provide good technology supportment for the dynamic monitoring of the oil and gas production. |
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