文丘里卷吸型气液分配器液体分配性能的结构参数研究

为了改善滴流床用的内卷吸型气液分配器的液体分散差的现象,提出了一种文丘里卷吸型气液分配器,并对其结构参数进行了参数化研究,定量认识卷吸型分配器的结构参数对其气液分配性能的影响。在冷态实验装置上进行了文丘里卷吸型气液分配器性能实验,建立了耦合群体平衡模型的欧拉-欧拉两相流模型,数值模拟了文丘里卷吸型气液分配器气液两相分配流动过程。冷模实验结合数值模拟,系统性考察了各结构参数对卷吸型气液分配器的液体分布均匀性、喷淋半径以及压降的影响。结果表明,采用具备缩-扩结构的文丘里管作为降液管能够有效提升卷吸型分配器的分布均匀度和喷淋半径,并显著降低压降。通过正交试验,获得了主要结构参数与分配性能的相关性,给出了结构参数与性能指标的经验关联式。降液管的扩张段是改善液体分配性能的关键结构,其扩张角为30°时液体分配性能最好。     

小液量抗堵分配器设计与性能研究

小液量抗堵分配器是针对传统粘稠液体分配器分布不均、结构复杂所设计的新型抗堵分配器。文中以空气和水为介质对分配器进行性能测试研究,针对初始测试结果中分配槽侧溢流堰斜面铺展效果不明显、大液量冲流、分配器紧固件漏液及导液板液体落点不稳定等问题,对分配器进行了优化设计。采用数学统计和作图对比2种分析方法对整个分配器测试结果做出评价。优化后,在液头高度下限和正常操作条件下,分配器中心和边壁区域分布点流量趋向均布,分布质量改善明显。结果表明:该分配器结构简单,操作弹性较大,分布点均匀,分配性能和抗堵性能良好,特别适应于小液量工况。     

淡液蒸馏塔液体分配器改造设计

本文对我公司重碱车间淡液蒸馏塔的液体分配器的两次改造情况进行了分析,指出了各种液体分配器的优点及缺点,明确了液体分配器在设计中应掌握的方法和原则。     

尿素装置二氧化碳汽提塔液体分配器固定方式改造

介绍美荷型480kt/a尿素装置二氧化碳汽提塔的液体分配器在垂直方向固定方法的改进,固定方法采用"压板+限位"结构,取消原焊接固定方式,新的固定方法在拆除时,不损坏液体分配器和列管上管口、减少拆装施工步骤、节省检修施工时间、降低设备检修成本和满足装配要求。     

一种新型板翅式换热器气液分配器分配特性的敏感性分析

两相流动分配不均是影响板翅式换热器换热效率的主要因素。传统的"先混合,后分配"方法不能解决在导流翅片中流向突变时气液分离引起的气液两相流体分配不均问题,因此采用"先分配,后混合"的理念提出了一种新型的气液分配器,气体和液体分别从各自的通道进入分配器,在分配器内均匀混合后进入换热器的翅片换热通道进行换热。通过对分配器内部流场的数值模拟,发现:分配器的气液分配不均匀度随流量的增加而增加,且不均匀度受液相流量的影响比气相大。该气液分配器的气液分配不均匀度相比传统封头结构降低了一个数量级,能够有效改善板翅式换热器层间通道的气液分配特性,提高板翅式换热器的换热效率。     

专利文献

液体洗涤剂及纤维柔顺剂盒组件以及洗涤剂分配器 本发明在于提供一种液体洗涤剂及纤维柔顺剂盒组件以及洗涤剂分配器。液体洗涤剂及纤维柔顺剂盒组件包含：被隔壁分隔,用于储存液体洗涤剂及纤维柔顺剂的主体,被隔壁分隔,可装卸的结合于主体的上部的盖。洗涤剂分配器包括：包含相互结合的分配器下部罩和分配器上部罩,并具有投入主洗涤中所需洗涤剂的区域、安装液体洗涤剂及纤维柔顺剂盒组件的区域、投入预洗涤中所需洗涤剂的区域的分配器罩和可装卸的结合于分配器罩的液体洗涤剂及纤维柔顺剂盒组件。     

固定床反应器中气液分配器的流体力学性能

设计了一种底部带有碎流板的新型管式气液分配器。以水和空气代替工业上的原油和氢气进行冷模实验。实验过程为:水由水箱经水泵抽出,经液体流量计计量后进入实验塔上部的气液扩散器,气液两相流经急冷箱冷却后同时向下通过分配器。进入到接液装置的液体通过橡胶管导入到放置在地面上的17个标有编号的量筒中,未进入接液装置的液体流入水箱,气体则排放到大气中。最后用U形管差压计测量分配器的压力降。实验研究了该分配器的分配性能、压力降损失、气液相操作弹性和分布不均度,优化并确定该分配器的结构形式和结构参数。结果表明,该分配器的最佳工作条件为:液相量为0.3m³/h左右,气相量为20~30m³/h。     

液体分布器的改进及应用

液体分布器是降膜式蒸发器的关键部件。分析了传统分布器的缺陷 ,并针对单盘式分配器进行了结构改进 ,提出了注意事项。改进后的应用结果证明效果良好。     

偏心进气式鼓泡反应器内气液流动的大涡模拟

采用气液两相流动的欧拉-欧拉大涡模拟，研究了偏心进气式鼓泡塔内气液两相湍流流动。模拟结果表明：气泡流的运动与气含率的分布与试验结果吻合良好，得到了气液两相湍流瞬态结构形成和演变过程；增大气速使涡结构剧烈变化，液体粘度增高限制了旋涡尺度的发展，反应器高径比减小使涡数量减少。     

大型急冷换热器裂解气流体分配CFD模拟

运用CFD软件对裂解炉大型急冷换热器进行CFD模拟,针对模拟结果,设计并优化入口气体分配器。最终模拟结果表明,通过增加入口气体分配器可以有效达到换热管中的流体分配均匀的要求。     

Design and experiment of a needle-type piezostack-driven jetting dispenser based on lumped parameter method

Micro liquid dispensing technology is widely used in the field of electronic packaging. This study presents a lumped parameter model of a needle-type piezostack-driven jetting dispenser, which can produce small high viscosity adhesive droplets with a high driving frequency. After describing the structural components and operating principles of the dispenser, a lumped parameter model for the system is derived by integrating the sub-models of the structural and fluid parts. According to the lumped parameter method, the fluid channels of the dispenser have been divided into several lumps to obtain a more accurate performance. Based on the proposed model, the jetting dispenser is designed and manufactured, and its performance is then evaluated through both computer simulations and experiments. Further experimental studies about its working properties based on the proposed dispenser are carried out. The results are used to guide the design and control works about the proposed dispenser.     

表观气速对气升式环流反应器性能的影响

利用计算流体力学(CFD)数值模拟方法.采用Euler法双流体模型研究了表观气速对气液两相气升式环流反应器的液体循环速率和气含率的影响.实验结果与数值模拟结果吻合较好.结果表明.气含率和液体速率在反应器内分布不均匀,气含率在相同的径向位置变化很小,液体速率随着表观气速的增加而增加.     

A computational fluid dynamics-based method to investigate and optimize novel liquid distributor

Liquid distributors have an important influence on packed towers' hydrodynamics and mass transfer performances. This work has designed a narrow-trough liquid distributor with stepped baffle plates to regulate liquid flow. The liquid mainstream is diverted layer by stepped baffles to realize the uniform distribution of liquid. The relationship between liquid flow and the baffle plates arrangement is studied by computational fluid dynamics (CFD) simulation. Furthermore, we put forward a CFD-based structural optimization scheme to arrange baffle plates in an arc shape, which leads to a uniform and stable flow of each distribution orifice in the range of liquid spray density of 5–120 m³·(m²·h)⁻¹. The simulation results agree with experiments, which proved that the novel liquid distributor has excellent performance. Compared with the traditional trough liquid distributor, the novel liquid distributor can provide more liquid drip points, more gas-phase channels, higher operating flexibility, and take up less space.     

偏心双桨搅拌流场及效果分析

生产工艺中需要聚苯乙烯粒子在液相苯乙烯中均匀悬浮与混合,要求底部固相不堆积,固相浓度分布均匀。为了达到理想的搅拌效果,本文研究了双桨的偏心率及转速对搅拌混合效果的影响。以底部椭圆封头,无挡板的反应釜和双层6折叶的开启涡轮式搅拌器为研究对象,用Fluent软件对搅拌器偏心时水的搅拌流场及聚苯乙烯粒子-苯乙烯固液搅拌进行数值模拟。模拟了不同偏心率和转速对搅拌流型、聚苯乙烯粒子浓度分布及能耗的影响,并用粒子图像测速法(PIV)实验验证水的搅拌流场。结果表明,偏心搅拌可使流体速度得到增加,桨叶下方的搅拌死区得到有效抑制;偏心率增大导致两侧的速度偏差越来越大,能量分布不均匀;偏心搅拌的聚苯乙烯粒子浓度分布比对中搅拌的更为均匀,可改善粒子在苯乙烯中的悬浮效果;相同搅拌效果的情况下,偏心率为0.15的功率消耗是对中搅拌的85%;对该固液搅拌时的最佳偏心率和最佳转速分别为0.15和95 r/min,此时固液搅拌混合效果最好,固相浓度分布最为均匀,消耗功率相对较少。     

CFD优化精馏塔板的液流状况

应用计算机对过程的模拟(仿真)研究是过程系统工程(process systems engineering,简称PSE)的重要组成部分,本文应用计算流体力学(computational fluid dynamics,简称CFD)模拟研究了液流强度和堰径比对精馏塔板液流状况的影响,并且模拟计算了改进塔板液流状况的两种方案:设置不等高入口堰和设置圆弧型的导流板,从模拟结果可以看出,以上两种方案都能够很好的达到优化塔板液流状况的目的。     

Computational Fluid Dynamics Modeling of Gas‐Liquid Two‐Phase Flow around a Spherical Particle

Microscale studies, which can provide basic information for meso‐ and macroscale studies, are essential for the realization of flow characteristics of a packed bed. In the present study, the effects of gas velocity, liquid velocity, liquid‐solid contact angle, and liquid viscosity on the flow behavior were parametrically investigated for gas‐liquid two‐phase flow around a spherical particle, using computational fluid dynamics (CFD) methodology in combination with the volume‐of‐fluid (VOF) model. The VOF model was first validated and proved to be in good agreement with the experimental data. The simulation results show that the film thickness decreases with increasing gas velocity. This trend is more obvious with increasing operating pressure. With increasing liquid velocity, the film thickness tends to be uniform on the particle surface. The flow regime can change from film flow to transition flow to bubble flow with increasing contact angle. In addition, only at relatively high values does the liquid viscosity affect the residence time of the liquid on the particle surface.     

Viscous Heating in a Wind Heater Device: CFD Simulation and Experiments

A wind heater device was developed based on three-dimensional computational fluid dynamics (CFD) simulation in order to generate heat using renewable energies, like wind. Frictional heat generation by viscous dissipation in a highly viscous liquid contained in the annular space between two rotating cylinders was investigated analytically and numerically. The results were also validated using experimental data, which showed very good agreement, the average error being low, with modeling data. The heat generated can be utilized for any general heating purpose. The effect of design, material, and viscous fluid properties on the efficiency of the heater was investigated. The simulation results showed that more heat energy is generated by increasing the oil viscosity and the rotational speed of the cylinders. Then, the best design, the one which generated more heat energy, was built. The results showed a reasonable compatibility with simulation outcomes.     

规整填料表面液体分布的计算流体力学

采用计算流体力学(computational fluid dynamics,CFD)中的VOF方法对规整填料表面液相分布进行了三维建模和仿真,实现规整填料内液相分布的可视化并得到了液膜厚度和有效相界面积比等相关定量信息。通过分析比较不同物系的数值模拟结果,发现液体的表面张力和黏度都对填料表面上液体分布有影响。表面张力越小,液相在填料片上分布越均匀,有效相界面积比越大,液膜厚度越小;黏度增加,有效相界面积比和液膜厚度也随之增加。较之于黏度对液相分布的影响程度,表面张力的影响程度更大,为主要影响因素。本文还提出一个预测有效相界面积比的新公式,并将数值模拟结果与已有文献进行对比,吻合性较好。     

新型多降液管塔板的流体力学性能及其流场CFD模拟

开发了一种流场均匀且液相处理能力大的新型多降液管塔板。本文以水和空气为介质，在内径1219mm的有机玻璃塔内，研究了新型多降液管塔板的流体力学性能。结果表明，在相同气液负荷下，相较于弓形降液管塔板，新型多降液管塔板具有湿板压降低、雾沫夹带量小和漏液少等优点。同时新型多降液管塔板继承了多降液管（MD）塔板液相负荷高的特点，在空塔动能因子2.4(m/s)·(kg/m³)^0.5的条件下，全塔喷淋密度仍可高达80m³/(m²·h)。对塔板上液相流场的流体流动特性进行了计算流体力学（CFD）分析，并将模拟结果与MD塔板进行对比。结果表明，新型多降液管塔板降液管的结构和排布方式使得塔板上液体流动更加均匀，预期可以获得更高的塔板效率。     

Application of kinetics and computational fluid dynamics in pinene isomerization

A reliable kinetic model to describe the effects of various factors on the reaction rate and selectivity of pinene isomerization is developed. Furthermore, computational fluid dynamics(CFD) is applied to simulate the solid–liquid dispersion in reactor. The catalyst Ti M is obtained by improving the composition and structure of hydrated titanium dioxide. The kinetic equation of pinene isomerization is deduced based on reaction mechanism and catalyst deactivation model. The kinetic equation of pinene isomerization reaction is fitted, and the results show that the fitted equation is correlated with the experimental data. The rate and selectivity of pinene isomerization reaction are affected by the amount of catalyst, deactivation of catalyst, structure of catalyst, reaction temperature and water content of catalyst. The solid–liquid distribution of the reactor is calculated by computational fluid dynamics numerical simulation, and the solid–liquid dispersion in commercial scale reactor is more uniform than that in lab-scale reactor.