计算流体力学在制冷工程中的应用

近年来，计算流体力学被越来越多地应用到制冷领域中。计算流体力学(CFD)是流体力学的一个分支，用于求解固定几何形状空间内的流体的动量、热量和质量方程以及相关的其它方程，并通过计算机模拟获得某种流体在特定条件下的有关信息，是工程设计人员用于分析问题和解决问题强有力的和用途广泛的工具。本文对CFD在制冷各方面的应用进行了综述，并对CFD应用的优势和应用前景作了探讨。     

三维可视化技术在岩土工程中的应用研究

由于三维可视化技术是将空间数据信息转换成三维图形,对大量数据处理具有高效性和直观性,该技术在岩土工程领域中已经得到了广泛的应用。主要介绍可视化技术在岩体的三维建模、三维数值模拟分析及岩体结构的三维网络模拟研究中应用。从而证明了可视化技术在岩土工程中的应用研究中具有十分重要的意义。     

大型矿山岩土工程可视化模型与应用

为了在第一时间准确地为矿山的稳定性分析提供模型资料,矿山岩土工程可视化模型在其中起到了不容小觑的作用。它通过运用计算机组件技术,准确地得出了矿山岩土工程的信息特点,为工程师对矿山岩土工程问题进行分析提供了综合的信息,为其做出正确判断给明了方向。该模型使得矿山岩土工程信息在计算机图形中得以呈现。     

计算流体力学在暖通空调工程中的应用

简要介绍了暖通空调领域计算流体力学(CFD)技术的基本数学物理模型,并结合实例给出了CFD软件STACH-3在建筑内、外环境,特殊空调空间以及建筑设备等各个领域中的应用情况,从而说明CFD应用于指导设计和优化分析暖通空调工程问题的巨大潜力.     

三维可视化土石方计算在核岛负挖中的应用探讨

本文以某核电站核岛负挖工程为例,运用CASS和AutoCAD软件相结合的方式,实现了二维设计图纸与实测离散高程点数据基于实体建模和布尔运算的三维可视化土方量计算方法。以及如何运用该方法控制负挖精度、指导工程施工和减少超挖方量,最后,分别利用CASS软件中DTM法两期土方量计算功能和三维可视化土石方计算方法,对竣工实际开挖方量的计算精度进行了比较,验证了三维可视化土石方量计算方法的可行性。     

研发硬质合金的集成计算材料工程

用于研发硬质合金的集成计算材料工程是将微观(10~(-10)10~(-8)m)、细观(10~(-8)10~(-4)m)、介观(10~(-4)10~(-2)m)和宏观(10~(-2)10 m)等多尺度计算模拟和关键实验集成到硬质合金设计开发的全过程中,通过成分-工艺-结构-性能的集成化分析,把硬质合金的研发由传统经验式提升到科学设计,从而大大加快硬质合金材料的研发速度,降低研发成本.本文详细阐述了第一性原理计算、CALPHAD方法、相场模拟和有限元模拟等计算模拟方法及各种微结构表征和性能测定的实验方法,论述了其在硬质合金研发中所发挥的具体作用.基于集成计算材料工程,提出了从用户需要、设计制备和工业生产的3个层面研发硬质合金的具体框架.通过应用实例,展示了集成计算材料工程在新型硬质合金研发中的强大功能,为新型硬质合金的设计和开发提供了新模式.     

爆破工程费用计算方法探讨

爆破工程具有周期短、自成完整体系、技术管理严格的特点,但在费用管理上需进一步规范与整顿。本文阐述了工程费用的构成、调整及爆破工程费用的计算方法。     

爆破工程费用计算方法探讨

爆破工程具有周期短、自成完整体系、技术管理严格的特点,但在费用管理上需进一步规范与整顿。本文阐述了工程费用的构成、调整及爆破工程费用的计算方法。     

Mathcad Prime v2.0工程计算软件

如今,顶尖的工程师使用Mathcad来执行、记录和共享工程计算及设计工作。独特的Mathcad可视化格式和便笺式界面将标准的数学符号、文本和图形均集成到一个工作表中-使Mathcad成为知识捕捉、     

谈工程结构计算中计算机技术的应用

在工程结构计算中,应该合理的利用计算机的验算速度的快捷,但不能让计算机替代结构工程师的对专业知识的钻研、工程设计经验的积累、工程设计思想的思考、工程结构计算过程的理解。     

Numerical modelling and flow visualization of mixing of stratified layers and rollover in LNG

A numerical model has been developed to study the mixing of two initially stratified layers which are subjected to a uniform lateral heat flux. An important distinction is made between the free surface and the liquid/liquid interface with regard to the different flow characteristics of the two layers. In the upper layer where warm liquid is cooled at the evaporating surface, the convective circulation is featured by a strong downward core flow; in contrast, the fluid flow in the lower layer is mainly confined to the wall boundary and is much weaker. Flow visualization experiments show that mixing of two stratified layers generally involves two stages in sequence: migration of the interface and rapid mixing between the remaining liquids. The interface movement is due to entrainment mixing at the interface. When the two layers approach density equalization, the interface becomes increasingly unstable and the core flow in the upper layer is able to break into the lower layer. The base to side heat flux ratio appears to be a major factor in determining the mode and intensity of the subsequent mixing at a rollover incident.     

Parallel tsunami simulation and visualization on tiled display wall using OpenGL Shading Language

Tsunami simulation consists of fluid dynamics, numerical computations, and visualization techniques. Nonlinear shallow water equations are often used to model the tsunami propagation. Tsunami inundation is modeled by adding the friction slope to the conservation of momentum. The two-step second-order finite difference MacCormack numerical method can solve these equations. It is well suited for nonlinear equations and simpler for related application development. In addition, the finite difference method can be computed in parallel. The programmable graphics hardware allows general-purpose computing on graphics processing units (GPUs) to solve the MacCormack method in parallel to speed up the simulation. Tsunami simulation data can be loaded as textures data in graphics memory, the computation processes can be written as shader programs using OpenGL Shading Language so that the operations can be computed by graphics processors in parallel. We developed different versions of the tsunami simulation and visualization programs: (i) CPU-based, and (ii) CPU–GPU collaboration to implement the MacCormack numerical method. The performance results showed that graphics hardware accelerated simulation had a significant improvement in the execution time of each computation step. Real-time simulation and visualization are made possible by the programmable shaders. Furthermore, we achieved high-performance parallel visualization on a tiled display wall with a cluster of computers.     

基于Web的飞机装配可视化系统研究

针对目前国内航空制造企业飞机装配生产中所存在的装配质量与效率偏低、生产管理水平不高等问题,面向装配车间实际生产过程,设计开发了基于B/S结构的飞机装配可视化系统。首先,构建车间单一产品数据源信息模型,为不同角色成员开发相应功能模块;然后,使用DELMIA仿真装配过程,输出可视化文件;其次,使用ActiveX技术实现装配动画页面内的三维交互。最后,以某型号大型飞机舱门作为对象,集成验证了该系统的可行性与实用性。     

对工程管理信息化的几点认识

从作为信息化的一个领域和工程管理的工具方法两个角度分别对信息化和工程管理的内涵及特点进行了分析,并明确了工程管理信息化的概念和基本特征,提出了工程管理信息化的工作进程、信息系统的特点和构建的条件。     

A cross-disciplinary technology transfer for search-based evolutionary computing: from engineering design to software engineering design

Although object-oriented conceptual software design is difficult to learn and perform, computational tool support for the conceptual software designer is limited. In conceptual engineering design, however, computational tools exploiting interactive evolutionary computation (EC) have shown significant utility. This article investigates the cross-disciplinary technology transfer of search-based EC from engineering design to software engineering design in an attempt to provide support for the conceptual software designer. Firstly, genetic operators inspired by genetic algorithms (GAs) and evolutionary programming are evaluated for their effectiveness against a conceptual software design representation using structural cohesion as an objective fitness function. Building on this evaluation, a multi-objective GA inspired by a non-dominated Pareto sorting approach is investigated for an industrial-scale conceptual design problem. Results obtained reveal a mass of interesting and useful conceptual software design solution variants of equivalent optimality—a typical characteristic of successful multi-objective evolutionary search techniques employed in conceptual engineering design. The mass of software design solution variants produced suggests that transferring search-based technology across disciplines has significant potential to provide computationally intelligent tool support for the conceptual software designer.     

Neural systems engineering

The quest to build an electronic computer based on the operational principles of biological brains has attracted attention over many years. The hope is that, by emulating the brain, it will be possible to capture some of its capabilities and thereby bridge the very large gulf that separates mankind from machines. At present, however, knowledge about the operational principles of the brain is far from complete, so attempts at emulation must employ a great deal of assumption and guesswork to fill the gaps in the experimental evidence. The sheer scale and complexity of the human brain still defies attempts to model it in its entirety at the neuronal level, but Moore''s Law is closing this gap and machines with the potential to emulate the brain (so far as we can estimate the computing power required) are no more than a decade or so away. Do computer engineers have something to contribute, alongside neuroscientists, psychologists, mathematicians and others, to the understanding of brain and mind, which remains as one of the great frontiers of science?     

Experimental investigation of the hot cracking mechanism in welds on the microscopic scale

The results of the accurate experimental observations on binary Al-Si alloys are presented, which clearly demonstrate that the solidification cracking is a result of the accumulation of macroscopic tensile displacement in aβmicroscopic intergranular liquid film of segregates at the final stage of the weld metal solidification. The reconstructed mechanism of crack initiation provides a clear phenomenological interrelation between the cracking susceptibility, parameters of the welding process and properties of the base and filler material. The correspondent numerical model takes into account the effects of displacement accumulation as well as the influence of thermo-dynamical and thermo-mechanical properties of the welded material. It is successfully applied for development of technological means for elimination of the solidification cracking during welding of aluminium alloys AA6056, such as a multi-beam welding.     

Fluorescence enhancement in hot spots of AFM-designed gold nanoparticle sandwiches

We observe an enhancement of fluorescence from a single fluorescent sphere, which is sandwiched between two individual gold nanoparticles, forming a hot spot of strong field enhancement. The fluorescence enhancing hot spot is custom-designed by the deliberate assembly of gold nanoparticles with an atomic force microscope cantilever. The fluorescence intensity is monitored while the separation between the two gold nanoparticles is reduced by gradually pushing the gold nanoparticles closer to the fluorescent sphere. The fluorescence enhancement is maximal when the distance between the two gold nanoparticles is smallest, when the excitation polarization is parallel to the axis of the sandwich, and when the fluorescent sphere is positioned exactly on the axis connecting the two gold nanoparticles.     

Cloud computing and its impact on service level: a multi-agent simulation model

Supply chains are increasingly becoming more complex, making collaboration progressively difficult to establish and maintain. It is imperative to understand not only the consequences, but also the drivers of effective and efficient collaboration. In this study, we attempt to show how varying levels of collaboration impact service level and how cloud computing fosters these levels of collaboration. We introduce a framework detailing how cloud computing impacts three levels of collaboration: (1) information centralisation, (2) vendor managed inventory and continuous replenishment programmes and (3) business intelligence (BI) collaborative planning, forecasting and replenishment. In addition, we use multi-agent-based simulation to analyse how each level of collaboration (enhanced through cloud computing) impacts service level as measured by fill rate. Obtained results show that cloud computing can enhance all three levels of collaboration. Further, our results demonstrate that BI collaborative planning, forecasting and replenishment have significantly greater service level benefits in comparison to other collaboration levels.