共查询到17条相似文献,搜索用时 74 毫秒
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针对稠油水环输送的水环流动改进问题,提出稠油流动边界层在聚丙烯酰胺(PAM)水环作用下的模拟实验方法,基于自主研发设计的室内油-水两相流可视化环道实验装置,采用500#白油模拟旅大稠油,实验研究了稠油-水环状流外环水相中添加PAM前后的流型特征与阻力特性,评价了PAM对水环润滑的协同减阻效果,分析了PAM对水环流动稳定性的作用机理。实验结果表明:PAM对稠油-水环状流的流型特征与阻力特性均有显著影响,使环状流的分布区域缩小,其缩减区域转变为分层流和塞状流,当其为分层流时减阻作用丧失;当油相表观流速为0.23~0.90m/s时,PAM减阻率随含水率增加先迅速增大后缓慢减小,在测试范围内最高达35%。研究结果可为稠油水环输送工艺优化提供理论指导和技术支持,也可为稠油管输流动改进提供新理念与新方法。 相似文献
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为解决含水稠油采输时油水分离和降黏减阻的问题,采用Fluent软件对井下油水分离和润滑过程进行数值模拟,并设计出一种新型的润滑元件,使其能就地安装,形成高质量油水环状流,有效控制采出液的含水率,提高含水稠油井采收率,并降低后续原油处理成本。固定入口流速为0.6m/s,分流比为0.5,进行润滑元件结构的单因素分析。结果表明:流体在溢流口处径向速度极小,说明形成的油核几乎不存在偏心现象,轴向速度的存在有利于形成清晰的油水界面,从而利于形成高质量的油水环状流,经过元件的流体分离出部分水后轴向速度也得到了提升,有利于提高原油采收率。进行与仿真模拟相同工况下的室内实验,通过改变流速观察润滑元件的压降值与流型的变化情况。结果表明:合理的入口流速范围内,采用雷诺应力模型(RSM)与混合多相流模型(Mixture)计算模拟润滑元件内部流场情况具有较高的可信度。 相似文献
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依托流体可视化环道装置,设计并加工稠油掺气减阻模拟装置,实验研究水平管内两种稠油模拟油掺气流动阻力特性,拍摄不同气液流量比下的管流流型,分析不同实验条件下气相对稠油的减阻效果并建立相应的压降预测模型。结果表明:在气液比0~15范围内,共观察到六种流型,分别是泡状流、弹状流、分层流、段塞流、环状流、雾状流。220#与440#模拟油所对应的管路减阻率分别在气液比1.17和0.96时达到最大值48.19%和33.76%,当掺气比为0.9~1.2时,减阻率均可维持在20%以上。其机理可归结为空气使油-油接触转变为油-气-油接触,降低了混合相的层间剪切应力。Dukler法不适用于高黏气液两相流,所建立的稠油-气两相压降模型预测值与实测值吻合良好,平均相对误差在20%以内。 相似文献
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研究了水平管内不同液相介质(水、油和不同浓度的CMC溶液)对气液两相间歇流动压降的影响. 实验管道为内径50 mm的透明有机玻璃管,从入口到分离器长约30 m,实验段由2个长3 m的水平管组成. 共记录了320组不同表观流速下的压降信号:油相0.17~1.85 m/s,水相0.17~2.48 m/s,CMC溶液0.17~1.42 m/s,气相0.06~3.40 m/s. 结果表明,液相为牛顿流体(油或水)的气液流动,随着表观气相流速的增大,压降呈增加趋势;非牛顿幂率流体(不同浓度的CMC溶液)的管道流动,当流动指数低于一定值时,压降随气相流量的增加呈降低趋势,并且低于单液相流动的压降. Lockhart-Martinelli模型过高地预测了气-非牛顿幂率流体两相的压降. 相似文献
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依托流体可视化环道装置,设计并加工稠油掺气减阻模拟装置,实验研究水平管内两种稠油模拟油掺气流动阻力特性,拍摄不同气液流量比下的管流流型,分析不同实验条件下气相对稠油的减阻效果并建立相应的压降预测模型。结果表明:在气液比0~15范围内,共观察到六种流型,分别是泡状流、弹状流、分层流、段塞流、环状流、雾状流。220#与440#模拟油所对应的管路减阻率分别在气液比1.17和0.96时达到最大值48.19%和33.76%,当掺气比为0.9~1.2时,减阻率均可维持在20%以上。其机理可归结为空气使油-油接触转变为油-气-油接触,降低了混合相的层间剪切应力。Dukler法不适用于高黏气液两相流,所建立的稠油-气两相压降模型预测值与实测值吻合良好,平均相对误差在20%以内。 相似文献
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流动稳定性问题是稠油水环输送的难点。使用CFD软件,从油水密度差、黏度差、油水两相速度几个因素出发展开研究。模拟结果表明,缩小油水密度差会减小压降梯度降低偏心率增加输油效率η,η最高可达11.54;油相黏度的增加虽然会增加压降梯度但输油效率会提高,η最高可达92.47。变水速情况下,水速过小会形成大压降的分层流,稳定水环形成后水速过大会增大管输总流量减小输油效率;变油速情况,油速增长会增加压降梯度,输油效率存在峰值,存在最优速度范围。 相似文献
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针对稠油水环输送的中心油流偏心问题,提出稠油流动边界层在AFS-2水基泡沫作用下的模拟实验方法,设计加工相应的管流模拟装置及泡沫发生、注入与泡沫层生成系统.用201甲基硅油模拟稠油,实验研究稠油在水基泡沫作用下的水平管流阻力特性,分析泡沫与硅油的流速与流量比对硅油流动流型和减阻效果的影响.基于上部泡沫-下部液膜复合边界层假设,建立硅油-泡沫-液膜中心环状水平管流的压降预测模型.结果表明:20℃室温下,当泡沫与硅油流量比为0.2~0.5时,硅油流动减阻率高于70%,其机理可归结为油壁间形成了上部泡沫-下部液膜的复合隔离润滑层;理论预测值与实验测量值吻合良好,相对误差为-17.55%~9.76%. 相似文献
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稠油节能增输是解决常规原油日渐枯竭、保障原油接替的紧迫需求,然而稠油黏度高、流道黏附性强,使其输送异常困难,是稠油节能增效输送技术瓶颈。根据前期研究本文作者发现,活性水作用下稠油乳化降黏的同时可改变稠油与管内壁界面特性,以及稠油提高采收率——润湿性之润湿反转,提出管输稠油乳化降黏及其流固界面润湿耦合作用流动减阻新思路。本文基于国内外相关研究成果的系统分析,探讨稠油乳化降黏、流固界面润湿及耦合减阻的有效性,剖析活性水作用乳化/润湿耦合减阻存在的主要问题,理论分析稠油在管输过程中实现乳化/润湿耦合减阻的可行性。结果表明,乳化/润湿减阻思路在理论上是可行的,而且在表面活性剂作用下乳化降黏的同时管输流固界面润湿反转更容易实施,然而,乳化/润湿减阻实际应用缺乏充分认识尚需深入研究其相关科学问题;其深入研究有望理解与认识流固界面特性对流动阻力的影响作用,可解决管输稠油流动阻力之难题,将为稠油流动改进提供理论与技术支撑,在稠油管输节能增效方面具有广阔的应用前景。 相似文献
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Experimental investigations of the flow of water‐heavy oil mixtures at velocities typical of oil‐field gathering systems show that continuous water assisted flow at very low pressure gradients can be achieved. The principal criterion to be satisfied in establishing this desirable flow regime appears to be use of sufficient water, with the velocity also playing a role. It also appears that oil viscosity and water fraction effects on pressure gradient are small provided the beneficial flow regime is established. The flows resemble core‐annular flow, which has been observed previously in Bitumen froth and water‐heavy oil flows, with an oil layer on the pipe wall. However, the correlation for pressure gradient is somewhat different from that reported previously for Bitumen froth flows. 相似文献
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Core annular flow pattern, where a low viscosity liquid surrounds a very-viscous one, may be very interesting for heavy oil transportation. However, in oil production, oil and water rarely flow alone and gas is usually present. Despite several publications on liquid-liquid core annular flow, no much work has been done towards a proper characterization of the effect of gas on pressure drop. The aim of this paper is twofold: to provide a new data base on three-phase (very-viscous-oil/water/air) flow, and to propose a simple model for the determination of pressure drop. 相似文献
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The present study is aimed at an investigation of the pressure drop characteristics during the simultaneous flow of a kerosene‐water mixture through a horizontal pipe of 0.025 m diameter. Measurements of pressure gradient were made for different combinations of phase superficial velocities ranging from 0.03–2 m/s such that the regimes encountered were smooth stratified, wavy stratified, three layer flow, plug flow and oil dispersed in water, and water flow patterns. A model was developed, which considered the energy minimization and pressure equalization of both phases. 相似文献
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HUO Xiaoqian XU Ying WANG Jinghan ZHANG Tao MAIMAITI Aikebaier WANG Xigang 《化工学报》2021,71(12):5506-5514
Considering the influence of swirl attenuation, the pressure drop characteristics of gas-liquid spiral annular flow are studied, and the pressure drop prediction model of spiral annular flow is deduced. The swirl-straight ratio of pressure drop is defined as the ratio of pressure drop of swirl flow to straight flow, used to characterize the effect of swirl decay on pressure drop. The expression of swirl-straight ratio of pressure drop is derived by the method of dimensional analysis, and it has a strongly dependence on Lockhart-Martinelli coefficient and gas phase Froude number. Finally, the prediction model of pressure drop for gas-liquid swirl annular flow is obtained. The pressure drop characteristics of the swirl annular flow are experimentally studied in a horizontal tube with an inner diameter of 50 mm. The range of the gas superficial velocity is 10—16 m/s and the range of the liquid volume fraction (LVF) is 0.6%—4.8%. Through comparison with experimental data, the relative error of the pressure drop prediction model is within ±15%, which provides a method reference for engineering applications. 相似文献