Experiment Study On Water Holdup And The Mixture Viscosity Of Dispersed-flow For Oil-Water Two-Phase Pipe Flow

Horizontal and inclined pipeline flow of mixtures of oil and water is a common phenomenon in petrochemical industry.Oil and water are immiscible and have different physical and chemical properties,and easy to exchange mass and energy in the flow process,so the flow pattern of oil-water two-phase flow show high randomness,instability and polymorphism.For oil-water phase flow,if the mixture velocity is relatively high,the of dispersed-flow will be formed.Under different flow conditions,the emulsion may be a Newton fluid or non Newton fluid,which makes the calculation of pressure drop more complicated.Phase inversion will occur when the mixture water holdup reaches a certain value.Dispersion of oil drops in water becomes dispersion water drops in oil,the rheological characteristics of the dispersion and the associated pressure drop change abruptly,and energy 1oss will increase.The accurate prediction of water holdup and emulsion viscosity is the basis of the calculation of pressure drop,and it can provide a theoretical basis for parameter design and process optimization.In this paper,the experimental and theoretical research are carried out on the water holdup and emulsion viscosity in the oil-water two phase pipe flow.(1)Simultaneous white oil and water flows in 60mm ID and 9.2m length transparent glass tube are investigated,observing flow pattern with high speed camera,measuring pressure,temperature,flow on line,measuring the water holdup and emulsion viscosity.(2)An approach has been taken to develop a flow characteristics-based model to calculate the water holdup for no-slip oil-water two-phase flow.This approach considers two flow patterns,stratified flow and stratified flow with mixing at the interface.Predicted values of model is compared with experimental data for white oil-water pipe flow.For stratified flow model,reveals that the critical inlet water fraction is approximately 35.5%and about 55.17%for three-phase segregated flow model when Uo-Uw.(3)Five kinds of commonly used water holdup prediction models are compared.The Nicholas-Witterholt model is found to give the best prediction.Considering the influence factor of pipe angle and inlet water fraction,and modified Nicholas-Witterholt model,then the Nicholas-Witterholt model ? is obtained.The experimental data of the test and JG Flores' are brought into the model and found that the average error of the model is about 10%,and has a certain generality.(4)Phase inversion will occur when the inlet water fraction is about 30%.Near the phase inversion point,the properties of the oil-water mixture and the pressure drop will change sharply.Compared with the Yet model and other common used reverse phase prediction models,the prediction results of Brauner&Ulmann model are the closest to the experimental results.(5)Comparing the the prediction results of different viscosity prediction models,finally,Pal(1993)model is selected for correction.Considering the water holdup,mixture velocity and pipe angle and other factors,modified multiplication factor ? in the model.Finally,a modified Pal(1993)correction model with high prediction accuracy was established.The new model can predict the emulsion viscosity in horizontal and horizontal oil-water flow well.