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预测均匀流化床反应器的压降及流动状态是过程工业长期以来的热点问题。利用CFD软件Fluent对流化床反应器气固两相流动状态进行模拟,使用欧拉方法,即颗粒相被当做"拟流体"进行处理,验证了在设计操作速度下流化床反应器具有较好的流化效果。 相似文献
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基于计算流体力学理论,采用CDF软件包中的Fluent软件建立了气固两相流在气力输送管道中的密相输送模型,对散状物料在气力输送水平管和竖直管内的流动过程进行模拟,得出了散状物料分别在水平管和竖直管的密相流动状态,可为气力输送系统的研究和设计提供参考依据。 相似文献
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采用CFD软件对折板式除雾器的流场进行数值模拟.建立了数学模型,对气体相采用基于雷诺时均方程的SST κ-ω湍流模型封闭N-S方程,对液滴相采用基于Euler-Lagrange的DPM方法.通过改变除雾器的结构参数板间距和工作参数进口气速模拟气液两相流场,分析这两种参数对压降的影响,这对折板式除雾器的优化设计有一定的指... 相似文献
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使用油相作为分散相,初始管中充满水,其中水作为连续相,运用Fluent模拟软件中的混合模型对垂直管中油水两相流动进行数值模拟,用Gambit建立流场模型,采用Mixture模型进行模拟,得到相应的速度分布云图、速度矢量图、压力分布图。模拟结果表明,油滴在挤出后开始经过一段加速距离,之后以一定的速度开始匀速上升,液滴之间没有相互干扰。该结果与实验中观察到的现象一致,说明运用Fluent模拟软件进行的数值模拟结果是可靠的,能对实验现象进行很好的预判。 相似文献
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A.K. Gupta 《Chemical engineering science》2008,63(22):5496-5502
Displacement of immiscible fluids is important in sub-surface processes such as enhanced oil recovery, oil sand processing and detergency. In this study, simulation of an oil droplet deformation on a solid substrate in simple shear flow has been carried out using computational fluid dynamics tool (Fluent 6.3) and the shape of the oil droplet is compared with that of the experimental observation. The dynamic behavior of a two-dimensional oil droplet subject to shear flow in a closed channel is considered under the condition of negligible inertial and gravitational forces. The volume of fluid method is used in Fluent to determine the dynamics of free surface of the oil droplet during the fluid flow. The oil droplet deformation increases with the increase in capillary number, Reynolds number and size of the oil droplet. The deformation of an oil droplet attached to channel surface in simple shear flow is studied experimentally in laminar flow through visual observation using microscope (Ziess, SV11 APO) with high speed camera (PCO). Aniline and isoquinoline was used to form oil droplet and distilled water was used as shearing fluid. The deformation of aniline and isoquinoline droplets was recorded using a high speed camera connected to a PC. The recorded image was replayed and the deformation of aniline and isoquinoline droplets was analyzed using Axio Vision software and compared with the results obtained from CFD simulation. The deformation of different sizes of aniline and isoquinoline droplets at different flow rates of shearing fluid and with time are well predicted by the CFD simulation. 相似文献
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Xuemei Xuan Wenjie Lan Xinyong Xu Shaowei Li 《American Institute of Chemical Engineers》2023,69(12):e18221
Droplet size and interfacial tension are key parameters related to two-phase flow. However, current methods for measuring these parameters are usually based on visualization and are therefore not applicable for invisible two-phase flow systems. Moreover, real-time determination of interfacial tension is difficult because conventional methods cannot be employed in the flow field. This study presents a novel method for simultaneously measuring the droplet size and real-time interfacial tension in a two-phase flow system. A T-shaped microdevice was designed and integrated with the two-phase flow equipment. The pressure variation as the droplets flowed through the microdevice was used as a probe to detect the two key parameters, that is, visualization is not required. Monodispersed and multidispersed droplet flows in different equipment were used to verify the method. Both the droplet size distribution and real-time interfacial tension can be determined using the developed approach. 相似文献
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针对传统流动共聚焦法两相流注入结构复杂,外部封装体积大的问题,本文开展了毛细管中微液滴生成的相关技术研究,借助商品化T形管,提出了一种基于T形共流聚焦结构的液滴生成方法。该方法不但简化了两相流的注入结构,较好地解决了封装难的问题,而且便于对液滴生成的相关参数开展进一步研究。对于液滴生成的相关参数,本文深入研究了液滴生成中液滴尺寸、流速比和生成频率之间的关系;通过正交试验深入研究了流速比、出口锥角角度和出口管径对液滴均一性的影响,其影响的主次顺序为:锥角角度>流速比>出口管径,在最优参数锥角角度为4°,流速比190∶1,出口管径72μm的条件下,所生成液滴平均体积为8.3nL,生成频率0.7Hz,均一性0.011。 相似文献
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利用高速摄像仪研究了截面为400 μm×400 μm Y聚焦型微通道内磁流体液滴在矿物油中的生成过程。以水基磁流体EMG 807为分散相,含4%表面活性剂Span-20的矿物油为连续相。实验观察到了3种流型:弹状流、滴状流和喷射流。分别考察了两相流量、连续相毛细数及磁感应强度对液滴尺寸及生成过程的影响。结果表明:可通过改变两相流量及磁场调控液滴尺寸。当分散相流量不变时,液滴尺寸随着两相流量比的增加而减小。液滴尺寸随着连续相毛细数及磁感应强度的增加而减小,随着分散相流量的增加而增加。以两相流量比、连续相毛细数和磁Bond数为参数提出了一个液滴尺寸的关联式,预测值与实验值吻合良好。 相似文献
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In this paper, the droplet transport and deposition in the turbulent airflow inside a wave-plate mist eliminator was studied using an Eulerian–Lagrangian computational method. The Reynolds Stress Transport Model (RSTM) with standard wall functions and with enhanced wall treatment was used for simulating the airflow field. A computer code for solving the Reynolds-averaged Navier–Stokes (RANS) equations in conjunction with the RSTM on two-dimensional collocated unstructured meshes was developed. For droplet trajectory analysis, another computer code was developed that accounts for the drag and lift forces action on the droplets. The Eddy Interaction Model (EIM) was used to model the droplet dispersion in turbulent airflow. The gas flow code was validated by comparing the computational model results for a fully developed asymmetric channel turbulent flow with the experimental data. Then the airflow and droplet trajectory analysis were performed for a mist eliminator with smooth walls and the resultant removal efficiency curves were evaluated and compared with the available experimental data. The results showed that the enhanced wall treatment improved the predictions of the droplet removal efficiency especially for small droplets in which the removal efficiency was lower than 50%. On the other hand, the Reynolds Stress Transport Model (RSTM) with standard wall functions cannot predict the removal efficiency correctly, especially for low gas velocities. 相似文献
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波纹板间油滴的Stockes浮升模拟分析 总被引:1,自引:1,他引:0
在分析油滴的Stockes浮升原理的基础上,应用Fluent6.0就波纹板间连续相入口速度、油滴粒径对Stockes浮升轨迹的影响,计算了多种工况,得到了油滴在波纹板间能否浮升到上板面聚集变大,除了取决于连续相的入口速度外,还取决于油滴的粒径。模拟结果表明,连续流场速度大小对油滴的Stockes浮升时间影响不太,浮升时间主要与油滴粒径有关,其计算结果为聚结波纹板的优化设计提供理论参考。 相似文献
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旋风分离器分离效率高,不易堵塞,用于天然气脱蜡效果显著。通过CFD软件Fluent模拟CYG-S型天然气脱蜡旋风分离器的两相流场,得到了旋风分离器内的压力、切向速度、轴向速度分布。对比了不同入口速度下的模拟与理论计算的分割粒径x50,发现具有很好的吻合度,两相模拟有一定的可靠性。结果表明:在旋风分离器锥段底部靠近壁面处的石蜡液滴质量浓度较高;随着进口流量的增加,旋风分离器分离效率提高,当进口流量为1000 m3/h时,x50可以达到5.3 μm;大粒径液滴的分离效果明显,但在所研究的进口流量范围内,进口流量的变化不能明显地影响粒径小于5 μm液滴的分离效率;柱段和锥段长度的增加使得旋风分离器的整体长度增加,延长了液滴在旋风分离器内的停留时间,提高了旋风分离器的分离效率。 相似文献
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利用高速摄像仪对十字聚焦微通道内液滴在黏弹性流体中的生成过程进行了实验研究。微通道截面为600μm×600 μm 的正方形结构,采用硅油作为分散相,含0.3%表面活性剂十二烷基硫酸钠(SDS)的聚环氧乙烷(PEO)水溶液(质量分数分别为0.1%,0.3%,0.6%)为连续相。实验观察到了弹状流、滴状流和喷射流3 种流型。对弹状流型下液滴生成过程的颈部动力学进行了研究,考察了两相流率、连续相毛细数及弹性数对液滴尺寸的影响。结果表明:弹状液滴尺寸随连续相流率、毛细数及弹性数的增加而减小,随分散相流率的增加而增加,连续相弹性对液滴尺寸的影响相对较小。以油水两相流率比和连续相的毛细数及Reynolds 数为变量建立了弹状液滴尺寸的预测关联式,预测值与实验值吻合良好。 相似文献
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在含聚丙烯酸钠(PAANa)的硫酸铵(AS)水溶液中,进行丙烯酰胺(AM)/丙烯酸(AA)/甲基丙烯酸甲酯(MMA)双水相共聚合反应,制备阴离子型聚丙烯酰胺水溶性聚合物分散液。采用动态激光光散射(DLS)在线检测了双水相聚合初期液滴形成及生长规律,发现液滴在反应初期存在聚并现象,滴径分布先变宽后变窄。采用气相色谱检测了共聚过程中各单体的残余量,推算聚合物链结构组成:反应前期聚合物链以AM和MMA链节为主,反应中期聚合物链以AM链节为主,反应后期聚合物链以AA和AM链节为主。提出了AM/AA/MMA双水相共聚过程的成滴机理,其中聚合物链上AA链节所带有的负电荷是聚合产物稳定分散、不易于凝聚的重要因素。 相似文献