Study On Flow Characteristics Of Oil-Water Two-Phase Flow In Inclined Pipe

Multiphase flow has been a hot topic for many scholars to study.Oil-water two-phase flow is the research focus and difficulty in this field.In this paper,emulsion stability and emulsion transport were studied successively by experimental and numerical simulation methods respectively for emulsified transport of heavy oil in inclined tubes.In terms of flow pattern transition,through the research of domestic and foreign research scholars,the transition criteria and influencing factors of stratified flow and dispersed flow in oil-water two-phase flow in inclined pipe are expounded.In terms of pressure drop law,this paper introduces and analyzes the main factors affecting the pressure drop of oil-water two-phase flow in inclined pipe,and discusses the accuracy of existing pressure drop calculation model and pressure drop prediction.It is more difficult to collect and transport heavy oil than to collect crude oil.In the process of transportation,it is often necessary to add a surfactant to form a stable oil-in-water emulsion.In the experiment,two kinds of compounding systems were selected to determine the stability of the emulsion by dynamic and static methods.The first one:the initial viscosity change rate K is used to measure the stability of the emulsion,and SDS is used as the main agent in the compound system.The results showed that the stability of oil-in-water emulsion formed by 0.14%SDS and 1-pentanol,APG and PEG with a mass fraction of 1.2%was K_PEG/SDS>K_{1-pentanol/SDS}>K_APG/SDS.The oil-in-water emulsion formed by the APG/SDS has the best stability,and the oil-water interfacial tension is 0.046.The second one is to determine the stability of the emulsion by using the static observation water fraction method,and select Na₂CO₃ and APG as the main agents,respectively.It was found that the stability of the emulsion formed by using 0.1%APG as the main agent and 0.4%Na₂CO₃ as the auxiliary agent is better than that of the emulsion with 0.1%Na₂CO₃ as the main agent and 0.4%APG as the auxiliary agent.The interfacial tension is 0.049.Finally,the VOF model was selected by numerical simulation to simulate the flow of different oil-water two-phase flow in the inclined tube?15^o,20^o,30^o,40^o?.The simulation found that it was within the range of the set inlet flow rate?0.4 m/s-1.6 m/s?and water content?20%-80%?.Flow pattern:The high-viscosity oil-water two-phase flow under the above inclination angle flows in a slug flow or an annular flow.The oil-water two-phase flow after the addition flows in an inclined tube in a stratified or dispersed flow.Pressure drop:At the same water content and inlet flow rate,as the angle increases,the pressure drop gradually measured but the change is not significant.At the same time,in order to find the main factors affecting the pressure drop during the oil-water two-phase flow in the inclined pipe,the angle?A?,velocity?B?and water content?C?are selected as the main factors,and the minimum pressure drop is used as the evaluation index.The orthogonal experiments was designed and analyzed.It is found that the inlet flow velocity has the greatest influence on the pressure drop,the water content is the second,and the inclination angle is the least.The optimal combination is A₂B₁C₂.This combination has the least influence on the pressure drop of the oil-water flow process in the inclined pipe.