Numerical simulations of airflow and droplet transport in a wave-plate mist eliminator

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.     

A Rigorous 2D Approximation Technique for 3D Waveguide Structures for BPM Calculations

We propose a rigorous 2D approximation technique for the 3D waveguide structures; it can minimize the well‐known approximation errors of the commonly used effective index method. The main concept of the proposed technique is to compensate for the effective cladding index in the equivalent slab model of the original channel waveguide from the modal effective index calculated by the nonuniform 2D finite difference method. With simulations, we used the proposed technique to calculate the coupling characteristics of a directional coupler by the 2D beam propagation method, and the results were almost exactly the same as the results calculated by the 3D beam propagation method.     

填料的形状对导电性复合材料性能的影响

以填料的形状和尺寸控制复合材料的性能是一个重要方法.选用了三种镍粉和不锈钢纤维,研究了它们对复合材料的导电性和力学强度的影响.结果表明,当填料的体积含量达到某临界值时,电阻率会发生突变,粒度愈小,形状愈不规则,该临界值愈小;同时,随着填料含量的增加,拉伸强度和冲击强度都是先升后降,转折变化时的体积含量都大于相同填料的材料电阻率陡峰时的临界值,这种变化规律都取决于材料的结构。     

光纤与有机聚合物脊形波导的耦合损耗分析

光纤与有机聚合物脊形波导的耦合是有机聚合物波导器件封装中关键的一步,它直接影响器件的插入损耗.本文利用广角有限差分束传播法和有效折射率法对光纤与有机聚合物脊形波导的耦合损耗进行分析,得出了如下结论:1)耦合损耗随着错位、间隙、夹角的增大而增大;2)因错位而引起的耦合损耗在所有耦合损耗中占有主要位置.     

SOI矩形光波导定向耦合器的研究

提出一种利用有效折射率方法分析SOI矩形光波导定向耦合器的理论,并且取得了与精确解非常吻合的结果,最后得出了一些有用的结论,对分析和设计光波导定向耦合器有一定指导意义.     

基于企业整体模型的设备数据管理系统

介绍了企业整体模型(Enterprise Integrated Model，简称EIM)的概念，分析了设备数据的静态属性和动态属性及其与企业各职能域间的映射关系。采用客户机／服务器模式，建立了以设备BOM为导向贯穿设备全生命周期的设备数据管理系统，解决了设备数据与企业各部门数据的共享和集成，实现了设备数据的有效管理。     

D/S架构即时型植物信息系统的开发设计

在对植物信息系统的开发设计过程中,提出了结合即时通讯技术,同时弥补C/S与B/S混合结构缺陷的新软件架构D/S(Desktop/Server),并以D/S为框架,建立即时型植物信息系统模型.通过对该模型中各模块的作用及相互关系的分析,阐述了业务流程与数据建模相结合的设计出发点,并通过对系统结构及主要技术实现的剖析,进一步说明该设计方案的优越性和实用性.     

Comparative efficiency evaluations of four types of cooling tower drift eliminator, by numerical investigation

This work presents a comparative evaluation of the performance of four types of wave-plate drift eliminator commonly used in mechanical cooling towers, with similar morphology. The droplet collection efficiency and the coefficient of pressure drop are numerically calculated, for values of inlet velocity and droplet diameter , with Reynolds number and inertial parameter roughly in the ranges 650≤Re≤8500 and 0.05≤P_i≤2.5, respectively. The numerical model has been validated through comparisons with numerical and experimental results taken from the literature, including additional configurations of horizontal wave-plate mist separators. The effects of considering the turbulence dispersion of droplets are studied, as well as the influence of the inertial parameter and the aspect ratio of the eliminator sample channel. Best results are obtained by using the SST k−ω turbulence model, with values of non-dimensional scaled distance to wall y⁺ comprised in the range 0.2–0.5, including the turbulent dispersion of droplets. A global correlation for the collection efficiency is proposed, as a function of the inertial parameter and the removal geometric parameter, which is introduced in this work. Finally, it is developed a procedure focused on establishing the overall efficiency for each type of eliminator, based in a key power function.     

Modeling of the contact between a rigid indenter and a heterogeneous viscoelastic material

In this paper, the contact problem between a rigid indenter and a viscoelastic half space containing either isotropic or anisotropic elastic inhomogeneities is solved. The model presented here is 3D and based on semi-analytical methods. To take into account the viscoelastic properties of the matrix, contact and subsurface problem equations are discretized in the spatial and temporal dimensions. A conjugate gradient method and the fast Fourier transform are used to solve the normal problem, contact pressure, subsurface problem and real contact area simultaneously. The Eshelby’s formalism is applied at each step of the temporal discretization to account for the effect of the inhomogeneity on pressure distribution and subsurface stresses. This method can be seen as an enrichment technique where the enrichment fields from heterogeneous solutions are superimposed to the homogeneous viscoelastic problem solution. Note that both problems are fully coupled. The model is validated by comparison with a Finite Element Model. A parametric analysis of the effect of elastic properties and geometrical features of the inhomogeneity is proposed. The model allows to obtain the contact pressure distribution disturbed by the presence of inhomogeneities as well as subsurface and matrix/inhomogeneity interface stresses at every step of the temporal discretization.     

建立大学生健康膳食与EIM指导系统关联性研究

大学生在校期间因受到诸多因素的影响,菜品的质量、不健康的膳食习惯将会在很大程度上影响他们在校期间的身体发育,对健康产生不同程度的影响,甚至造成慢性病的不良后果。本课题组对大学生不良饮食习惯进行了调查,针对可能引起的慢性病制定了对应的运动处方,以帮助大学生通过相关的运动和养成健康的膳食习惯,树立健康的膳食观念。