气液并流吸收过程中液相近界面浓度分布的全息干涉测量

1 INTRODUCTION Mass transfer across free interface of gas-liquid flow is of extensive importance and is encountered in most industrial applications. A close investigation of concentration distribution near the interface is helpful to understand mass transfer phenomena, to guide the development of transport theories, and to optimize the design of gas-liquid contact equipment. Laser holographic interference technique provides a precise and noncontact measurement method for measuring the tran…     

基于神经网络的多效并流蒸发过程的模拟方法

本文提出一种基于神经网络的多效并流蒸发过程的模拟以及优化算法，并以一简单三效并流蒸发过程为例，详细阐述了神经网络模拟算法的具体步骤。该算法具有对初始值要求不高、收敛速度快，全局收敛性好的特点。     

并流喷雾干燥塔的计算机辅助设计研究

喷雾干燥广泛应用于众多工业品的生产。图解积分法是目前求喷雾干燥塔塔径和塔高常用的方法，但是图解积分法计算过程繁琐，误差大且无法编程计算。因此将喷雾干燥塔中雾滴运动的阻力系数与雷诺数之间的关系用误差极小的多项式取代图解积分法中使用的误差较大的Allen公式，并给出了喷雾干燥塔塔径和塔高的积分式，利用四阶复化高斯～勒让德数值积分法计算喷雾干燥塔塔径和塔高，有效地提高了设计精度，利用可视化语言Visual Basic6．0开发计算机辅助设计软件。算例表明：计算机辅助设计方便、结果精确，为进一步实现并流喷雾干燥塔的优化设计提供了一个有效的设计方法与手段。同时建立以年总费用为目标函数的并流喷雾干燥塔经济评价模型，对并流喷雾干燥塔的设计参数如空气进出口温度、空气进口湿度等参数进行经济评价与分析，探讨其对并流喷雾干燥塔运行费用与年总投资的影响，对实现并流喷雾干燥塔的优化设计，降低能耗，节省投资具有一定的参考价值。     

Comparison of Methanol with Formamide on Separation of Nitrogen Heterocyclic Compounds from Model Coal Tar Fraction by Batch Cocurrent Multistage Equilibrium Extraction

The separation of nitrogen heterocyclic compounds (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp), and phenyl ether (Pe) was examined by batch cocurrent three stages equilibrium extraction. The model coal tar fraction used as a raw material in this work was prepared according to the components and compositions contained in coal tar fraction (distilled temperature ranges: 240–265°C). An aqueous solution of formamide and that of methanol were used as solvent, respectively. The distribution coefficient of the entire NHC (NHCs) summed four kinds of NHC was much larger than that of the entire BAC (BACs) summed three kinds of BAC, Bp, and Pe. Irrespective of solvent used in this work, the NHCs was recovered more than 90% through three stages of the equilibrium extraction. The selectivity of NHCs based on BACs obtained through the 3 stages equilibrium extraction using an aqueous solution of formamide was higher 3.6–8 times than that using an aqueous solution of methanol. Furthermore, we investigated the recovery process of NHCs contained in coal tar fraction using the formamide experimental results obtained from this work.     

有固相析出的并流多效蒸发系统常规设计的模型与算法研究

建立了带有固相析出的并流多效蒸发系统的数学模型，模型的将系统中的固液相平衡关系和汽液相平衡关系用回归式表达，易于编程用计算机求解，避免了繁琐的手工计算。模型可以写成矩方程的形式，在特定情况下模型简化为没有固相析出的并流多交蒸发模型，提出一种高效的新算法－近代法求解模。算例表明，新虎法收敛速度快、收敛稳定性好。     

SCALE-UP OF PNEUMATIC CONVEYING DRYERS

Scale-up of pneumatic conveying dryers has until now been largely empirical. A theoretical model is outlined which predicts dryer performance effectively. It depends on some uncertain parameters, notably agglomeration and wall friction, but these can be found more accurately by checking the predictions against results from the small-scale dryer. The model can then be used to scale up to the full size dryer. The required duct length falls as the gas velocity is reduced and the duct diameter increased, subject to satisfactory conveying and dispersion at the feedpoint.     

并流共沉淀法合成Dy_(2)O_(3)-ZrO_(2)纳米粉体EI北大核心CSCD

采用并流化学共沉淀法合成了Dy_(2)O_(3)掺杂ZrO_(2)(DySZ)纳米粉体材料,系统研究稳定剂掺杂量、阳离子浓度、反应系统pH值和煅烧温度对粉体材料物相组成、晶体结构和微观形貌的影响。结果表明:不同合成工艺条件下,DySZ粉体材料均具有纳米尺度特征,球形颗粒尺寸为10~30 nm,Dy_(2)O_(3)的掺杂可以起到稳定晶型的作用;稳定剂掺杂量对DySZ粉体的物相组成具有明显影响,掺杂量为10%(质量分数)时可合成单一四方相结构的DySZ粉体;DySZ粉体材料的四方度和微观形貌对稳定剂掺杂量、阳离子浓度、反应体系pH值和煅烧温度均不敏感,但其平均晶粒尺寸随稳定剂掺杂量、阳离子浓度和反应体系pH值的升高略有降低,随煅烧温度的提高而显著增加。     

气液两相并流体系气含率的表达式及其应用

本文基于气液两相分相流模型和动量守恒原理,并结合若干假定,建立了气液两相并流流动体系的气含率一般表达式,给出了由测定压降利用该表达式在确定管内气液垂直向下并流体系气含率中的应用,验证表明Ｈｉｌｌ提出的气液两相垂直向上并流流动体系的气含率表达工为本文建立一般公式当θ＝９０°时的特例。     

Combinated Flow Pattern Map for Cocurrent and Countercurrent Air-Water Flows in Vertical Tube

Flow patterns for cocurrent and countercurrent air-water flows in vertical tubes (40 and 80mm I.D.) at volumetric flux densities of air and water in the ranges ?115–158 and ?100–102 cm/s were observed. A flow pattern map presenting the entire data of the observed flow patterns, i.e. bubbly, slug and annular flow for each mode of flow operation (upflow, countercurrent flow and downflow) were presented on the j_l vs. j_g plane. The flow pattern maps showed significant difference of flow pattern transition boundaries with upflow, countercurrent flow and downflow. Flow pattern transition curves were smoothly continuous with the change of the direction of water flow, on the other hand the change of flow direction of air showed complicated effect on flow pattern transition near zero j_g . Comparison of the present flow pattern data with the reported general flow pattern maps for upflow showed that the correlation of Taitel et al. for bubble-slug flow transition is applicable to both cocurrent and countercurrent air-water flows.     

Measurement System of Bubbly Flow Using Ultrasonic Velocity Profile Monitor and Video Data Processing Unit, (III)

The authors have developed a new measurement system which consisted of an Ultrasonic Velocity Profile Monitor (UVP) and a Video Data Processing Unit (VDP) in order to clarify the two-dimensional flow characteristics in bubbly flows and to offer a data base to validate numerical codes for two-dimensional two-phase flow. In the present paper, the proposed measurement system is applied to fully developed bubbly cocurrent flows in a vertical rectangular channel. At first, both bubble and water velocity profiles and void fraction profiles in the channel were investigated statistically. In addition, the two-phase multiplier profile of turbulence intensity, which was defined as a ratio of the standard deviation of velocity fluctuation in a bubbly flow to that in a water single phase flow, were examined. Next, these flow characteristics were compared with those in bubbly countercurrent flows reported in our previous paper. Finally, concerning the drift flux model, the distribution parameter and drift velocity were obtained directly from both bubble and water velocity profiles and void fraction profiles, and their results were compared with those in bubbly countercurrent flows.