槽式液体分布器分布性能的研究

文中以大型的工业用槽式液体分布器为研究对象,研究方法有理论计算、实验和流体模拟软件模拟。研究发现:传统的槽式液体分布器其分布孔的设计存在偏差,分布器分布管出口流量、一级槽自身液面稳定能力以及液面梯度都对分布器的分布性能有影响。文中提出了一种新型槽式液体分布器,有利于提高填料塔的效率。     

填料塔槽式液体分布器的设计

槽式液体分布器具有可将液体分布合理,气流阻力小,防液沫夹带,抗堵塞和操作弹性高等优点而被广泛应用。文章依据以往的设计经验,结合国内外关于槽式分布器的设计,试验理论,对槽式分布器的设计计算,结构分布等方面进行论述。     

变孔径直管液体分布器的研究与设计

本文研究了均匀开孔与非均匀开孔直管液体分布器的流量分配。结果表明,改变孔径可有效地提高流量分配的均匀性。根据修正动量方程和实验数据计算并关联了动量摩擦修正系数。对小孔阻力系数进行了测定和关联。提出了变孔径直管液体分布器的设计方法,并给出设计示例。     

液体分布器布液均匀性影响因素综合分析

布液均匀性是衡量液体分布器效果的重要指标。为了研究布液均匀性各影响因素对布液均匀性的综合影响,采用三元二次正交回归设计实验的方法,对孔径、孔间距和液位高度与布液不均匀度之间的影响进行研究。得出各因素与布液不均匀度的正交回归方程,通过回归方程系数及显著性分析表明各因素对布液不均匀性均有影响,其中在单因素中孔径影响最大,在交互作用因素中,液位高度和孔间距的交互作用影响最大,在二次项影响中布液高度影响最大。在实验范围内的最优点为(11.8,14,3.4)。     

变孔径直管液体分布器的研究与设计

本文研究了均匀开孔与非均匀开孔直管液体分布器的流量分配。结果表明，改变孔径可有效地提高流量分配的均匀性。根据修正动量方程和实验数据计算并关联了动量摩擦修正系数。对小孔阻力系数进行了测定和关联。提出了变孔径直管液体分布器的设计方法，并给出设计示例。     

槽式液体分布器预分布管的均匀性分析

为了提高槽式液体分布器预分布管流体分配的均匀性,把均匀开孔变成非均匀开孔Ⅰ、非均匀开孔(加卸压孔)Ⅱ两种开孔方式,借助计算流体力学软件FLUENT利用k-ε模型对其三维流场进行数值模拟求解。分析得出改变开孔直径,并加一卸压孔这种开孔方式下各孔的出流量、管内的静压和湍动能分布最均匀,适用于工程的操作。     

CO_2汽提塔的计算与分析

利用液体穿孔的流量公式,推导出CO_2汽提塔液体分布器上的液体分布孔流速与液位高度的关联公式,可计算出汽提塔单管负荷。根据湿壁塔内液膜厚度公式,计算出尿素-甲铵液在不同类型CO_2汽提塔中的停留时间。通过热力学计算,归纳总结了不同生产负荷下CO_2汽提塔的热负荷和传热系数。计算结果表明,理论计算值与实际生产数据基本吻合。     

槽内溶液的空气搅拌

本文研究了槽内溶液的空气搅拌、搅拌装置的设计方法。根据由实验得出的搅拌强度分布型式,分析了搅拌强度与风量、吹出孔孔径等因素的关系,认为设计时应按照电镀零件在槽内的排列,设置空气吹出孔;孔数一般为12～22只/米,孔径3～6mm;再按每只孔8～14L/min的风量计算总风量,并按空气吹管在溶液内的深度计算所需的空气动力。此种计算法与按溶液体积及按溶液的液面积计算风量的方法相比,更符合实际需要;计算所得的风量能保证搅拌效果,而且不会造成动力浪费和其他不良影响。     

一种补液管流量自动调节装置

<正>一般化工企业采用阀门控制储槽补液管的液体流量,但需要操作人员时常观察储槽液位高低,随时手动调节阀门的开合度来控制补液管内液体流量大小,以保证储槽内液位的合适高度。以手动调节阀门控制补液管液体流量对于盛装强腐蚀性及有毒有害介质的大型密闭容器,存在观测难度较大、操作危险度高、调节频率高、液位控制难度大、操作人员工作量大等问题。以下介绍一种补液管流量自动调节装量。1设计目的及设计原理     

横向流动对槽式液体分布器孔口出流的影响

以CFD模拟为工具,对槽内横向流动对孔口出流的影响进行了研究。研究结果表明:孔口的流量随着槽内横向流速的增加而减少。另外,研究结果还表明液位越低、孔口直径越小,孔口出流越容易受到横向流动的影响。对于处理量较大的槽式液体分布器,横向流动有可能导致大规模不良分布。因此,应对液体在分布器内的流动特性进行系统的研究,以避免形成大规模不良分布。     

垂直管外降膜的切向旋转沟槽型液体分布器特性研究

考察了布液器尺寸、操作温度以及流动工质质量分数、流率等的影响。利用实验数据回归了流体在切向旋转沟槽内流率系数和雷诺数的关系式,可用于工程设计。同时提出了管外切向旋转沟槽液体分布器的设计计算方法,由此方法设计加工的液体分布器已成功地用于工业余热回收的第二类吸收式热泵装置。     

Simulation of Orifice Flow Influenced by Lateral Flow in a Trough‐Type Liquid Distributor

A computational fluid dynamics (CFD) simulation is performed to investigate the influence of lateral flow on the orifice flow in a trough‐type liquid distributor. The discharge coefficients from the simulation are in good agreement with the experimental values, indicating that the CFD simulation is accurate in describing the outflow through orifices. The lateral flow near an orifice can change the velocity and pressure distributions of flow regions in front of this orifice, causing a decrease in the discharge coefficient. This phenomenon is supported by the theory of flow past a blunt body. An important implication derived from this finding is that the influence of lateral flow should be minimized in the design of a trough‐type liquid distributor, because the decrease in the discharge coefficient leads to non‐uniform outflow. The structure of a trough‐type liquid distributor is optimized to improve the liquid distribution performance by reducing the influence of lateral flow.     

A new streamlined bubble-cap distributor for high gas–liquid ratio and the liquid distribution mechanisms

The bubble-cap distributor is the most commonly used and critical internal for trickle bed reactors but holds the inherited disadvantage of liquid central aggregation when operating at a high gas–liquid ratio. A new bubble-cap distributor with a streamlined downcomer was developed in this paper to counter back the liquid aggregation and improve its comprehensive performance. The effect of the streamline parameters of the new distributor on liquid distribution was systematically explored by the coupled Euler–Euler-population balance equation (PBE) model. Compared with the classical and polyline converging–diverging structures, the results showed that the streamlined downcomer was a key to generating radial velocity of two-phase flow and reducing the liquid central aggregation for the bubble-cap distributor. The mechanism of well-distribution was explored for the new distributor. Lower converging and diverging angles enhance the distribution performance. A downcomer with a small converging angle and a 30° diverging angle was recommended for dispersing the central aggregated liquid column and acquiring the high distribution uniformity and spray covering circle. These data would be helpful to the optimal design and scale-up of the bubble-cap distributor in further industrial applications.     

填料塔内液体分布器均布性能的CFD模拟

针对适用于规整填料的槽式液体分布器的初始布液性能 ,在现有的经验参数基础上 ,我们利用商业计算软件FLUENT对特定条件下的液体分布时的流动情况进行数值模拟计算 ,所得结果基本符合实验情况。     

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.     

预分布管内流场的CFD模拟及实验验证(英文)

Liquid distributor is a very import internal for distillation columns. Pre-distributor is usually set on the top of distributor for initial distribution. Fluid flow in pre-distributor is a complex system of variable mass flow with many orifices and sub-branches. Consequently, the two phase modeling of pre-distributors was carried out and the homogeneous model with free surface model was applied. The numerical method was validated by comparing with experimental data. Using the simulated results for different pre-distributors, the impacts of inflow rate, location and orientation upon the outflow distribution were investigated. Furthermore, influences of the outflow distribution for pre-distributor on liquid uniformity in trough were also analyzed. The conclusions can be adopted for the struc-tural design of liquid distributor and pre-distributor of large scale.     

填料塔液体分布器的设计(续三) 第四讲 堰槽式液体分布器的设计

介绍堰槽式液体分布器的结构、特性、适用范围、设计参数和设计方法,并给出了一个工业设计实例。     

液体分布器分布质量评价体系综述

液体分布器是影响填料塔性能的关键部件,为了能更合理地对液体分布器分布质量进行评价,文中介绍了Moore分布质量、Preey作图法、L.Sp iegel实测法、K lem as分布质量、K illat分区法、L.Sp iegel润湿指数以及白跃华区域流量测量等几种目前国内外常见的分布质量评价方法,并对其各自优缺点及适用条件进行分析。通过对空分填料塔液体分布器结构形式进行研究,认为基于区域面积液体测量的评价方法更适用于对其液体分布质量进行评价。评价体系的正确选择有利于发现液体分布器存在的问题和提出适当的改进措施。     

基于Visual Basic的窄槽式液体分布器设计与实现

引用Visual Basic中的ActiveX技术,将Visual Basic的可视化设计与Excel强大的数据表结合,建立窄槽式液体分布器的计算与数据报表,所建立的程序运行可靠,操作方便,数据结果便于设计人员设计。克服了传统的窄槽式液体分布器计算工作量大,耗时费力,效率低的缺点。     

孔盘式液体分布器内液体流动对布液孔出流均匀性的影响

借助包括双欧拉均相多相流模型、VOF界面追踪方法和SST k-ω湍流模型的CFD模型,对孔盘式液体分布器内的流场对布液孔出流均匀性的影响进行研究。首先以单孔流动时的液体流量为标准值,通过与标准值的偏差来评估布液孔的出流不均。根据偏差的大小,可以衡量分布器内流动对布液孔出流的影响。然后结合孔前流动区概念对模拟结果进行分析,发现布液孔出流不均是由分布器内液体流动不均造成的。最后,提出了通过改变进料管位置来优化盘式液体分布器结构。计算结果表明,改变进料管的位置可以避免大规模不良分布,进而提高液体分布器的性能。