凤凰传媒中心刚性模型的风洞试验

通过对凤凰传媒中心刚性模型的风洞试验,分析研究了这种非大变形柔性的大跨屋盖结构的风压分布特性,得到了在不同风向角下外围壳体和中庭悬索膜结构表面的平均风压系数.结果表明:外围壳体的风压,除环形外侧主要正迎风面和环形内侧的小部分迎风面为正压外,大部分都为吸力;中庭悬索膜结构表面主要以吸力为主.     

45t AOD配气模型

针对传统AOD配气方式的缺点,研究了基于魏季和等的脱碳精炼数学模型的配气模型,使AOD脱碳配气可根据钢水碳含量的变化自动调整氧氩比、根据钢水温度变化自动调整供氧强度,以及根据炉役中炉容比的变化自动调整最大供氧强度。该模型应用于AOD不锈钢冶炼系统中,既提高了氧气利用率,又缩短了冶炼时间,而且吨钢氧耗和还原硅消耗也略有改善,取得了较好的效果,为AOD不锈钢冶炼智能化打下了良好的基础。     

应用炉气分析的转炉动态模型初步研究

运用物料平衡及反应平衡原理,利用炉气连续分析的数据,建立了转炉冶炼过程的动态模型.本模型的计算结果表明:(1)通过烟气流量、成分及原料中初始碳含量可动态地确定熔池中的碳含量;(2)以动态确定的碳含量为基础,经过热力学平衡分析,可确定熔池内温度及氧含量的动态变化.     

多方位粒子相互作用的格子气自动机法相变模型

介绍了近年来以流体力学和分子动力学为背景而发展起来的格子气自动机法,本文中,通过各方向移动粒子间的相互作用以及静止粒子与各方向移动粒子间的相互作用建立了相变模型.通过模拟液体中气泡的形成,可观察到微观的相变过程,并由此证明了此模型的正确性和有效性.     

4种经验模型在藏川杨光响应研究中的适用性

采用直角双曲线模型、非直角双曲线模型、直角双曲线修正模型和指数函数模型分别对藏川杨(Populus szechuanica Schneid)叶片光响应曲线进行了拟合与比较,探讨了几种模型在藏川杨光响应研究中的适用性.结果 表明:不同模型对同一种植物光响应曲线的拟合结果存在差异,采用非直角双曲线模型和直角双曲线模型拟合出的光补偿点(LCP)、最大净光合速率(Pmax)高于实测值,光饱和点(LSP)远低于实测值;函数模型拟合的最大净光合速率较为接近实测值;采用直角双曲线修正模型拟合的藏川杨叶片光响应参数均比较准确.     

广义细胞自动机与广义归纳逻辑因果模型

在勃克斯(A.W.Burks)构筑的描述因果世界的细胞自动机的基础上(属归纳概率逻辑范畴),提出了可综合处理随机不确定性与模糊不确定性的广义细胞自动机与相应的广义归纳逻辑因果模型,解决了原模型中未曾解决的主因判定与因果扰动响应的问题,并找到了它在智能控制中的应用.     

基于LF钢包炉气液两相区的三维Euler模型计算及分析

针对某钢厂85t圆筒型LF钢包炉，建立起了气液两相流三维Euler模型，通过对两相区基本参数气含率和速度分布的分析，得到钢包内气液两相区呈倒锥型结构的结论，很好地验证了全浮力模型理论。     

事故进程中操作人员决策的认知模型

介绍和分析了Worledge认知模型并对已知转移率的条件下各种事故进程的人的不响应概率进行了分析与比较,并通过模拟机实验中采集的数据进行了模型的验证与分析核电站操作员的失误概率.     

在安塞乐米塔尔印第安纳海港第二炼钢厂BOF车间没有底吹和抑制罩燃烧系统采用炉气分析预测碳模型

炼钢车间可以利用炉报分析仪以及BOF工艺过程得到的数据模拟终点熔池碳含量。该文分享了开发在BOF中预测碳模型,没有底吹／底搅拌能力以及此模型面对的挑战和极限。     

模糊神经板形控制模型在冷轧带钢生产中的应用

提出了基于模糊切换的模糊控制和神经元控制相结合的板形双模控制思想,并结合模糊神经板形预报和模糊神经板形模式识别以及在线模糊神经双模控制器建立1220 mm五机架冷连轧机板形在线控制系统,对冷轧带钢的板形进行控制.结果表明,控制效果好,超调小、响应快、无静差、鲁棒性强,板形控制精度进一步提高,达到了板形在线智能控制之目的.     

Design and Wind Tunnel Performance Testing of a New Omnidirectional Roof Vent

Low-slope roofs are subjected to potentially high levels of suction pressure as reported by Baskaran and Savage in 2003 in “Wind pressure measurements on full scale flat roofs.” Traditional roof assemblies are prone to failure when the low pressure on the roof surface instigates a transfer of forces to the roof membrane. Existing pressure-equalized roof systems use the power of the wind to transmit low pressure to the space immediately beneath the roof membrane, pulling the membrane down to the roof surface. The object of this study is the design of a wind vent which, when coupled with a single-ply roof membrane in a complete roof assembly, will successfully equalize low pressure throughout the entire field of the roof. The proposed wind vent differs from existing equalizer valves in its use of the Bernoulli effect to create low pressure. The vent is omnidirectional and contains no moving parts. Future study will be required to determine the tributary area of each vent and other roof system parameters.     

上海世博会主题馆超大型钢屋盖滑移安装技术

通过介绍2010年上海世博会主题馆工程的钢结构滑移安装技术,论述了在施工场地条件受限制的情况下,采用滑移安装技术对工程进度和安全的促进和保障作用,并对该工程带悬挑滑移和带柱顶滑移施工方案的实施情况进行了重点分析.     

中国2010上海世博会给水排水新技术解读与展望

借助中国2010上海世博会的契机,对给水排水新技术情况进行了全面调研,总结了世博会上展示和应用给水排水新技术的展馆和地标,解读了各个国家和地区向世界展示的给水排水方面的最新技术和先进理念,展望了城市给水排水技术未来发展的动态及趋势,指出了世博后上海给水排水技术的重点发展方向.     

Optimizing the Wind Uplift Resistance of Mechanically Attached Roof Systems

Wind dynamics on a mechanically attached single-ply roofing assembly can lift the membrane and cause fluttering, introducing stresses at the attachment locations. To identify a component in a system that has the weakest resistance against wind uplift forces, a dynamic evaluation method is beneficial. Over the past 10 years, a number of mechanically attached systems were constructed and exposed to simulated dynamic wind uplift forces using the Dynamic Roofing Facility at the National Research Council of Canada. This paper presents data from this ongoing investigation that will help system designers to maximize wind uplift ratings by choosing the appropriate roof components at the early design stage or by replacing/adding components during reroofing to improve uplift resistance. By diagnosing roof system failures, one can identify the weakest link and select design alternatives that can improve the wind resistance. Through a case study, this paper concludes with a procedure for system optimization.     

Application of Proper Orthogonal Decomposition Method in Wind Field Simulation for Roof Structures

The weighted-amplitude wave superposition method and the proper orthogonal decomposition (POD) technique are first introduced. Then the POD technique combined with a wind field reconstruction method for a flat roof is studied. In the meantime, wind field extension using B-spline interpolation and the wind field reconstruction are verified. On this basis, a three-step simulation algorithm to generate wind field is presented for roof structures. In the proposed algorithm, the weighted-amplitude wave superposition method, the POD technique, and the B-spline interpolation technique are combined together. In contrast to the existing algorithms in frequency-domain-based simulation, the proposed one can reduce the computation cost remarkably. In order to demonstrate the capability and efficiency of the proposed algorithm, an engineering example, the wind field simulation for a large-scale roof of the Foshan Century Lotus Stadium, is illustrated. The results show that the proposed algorithm is very efficient with sufficient precision. Therefore, it is advantageous in wind resistance analysis for large-scale roofs.     

Bivariate Quasi-Steady Model for Prediction of Roof Corner Pressures

Extremely high-suction pressures generated beneath the conical vortex flow in the roof-corner region have a devastating effect on the building roofs in high-wind events. The application of quasi-steady theory near the roof corners of low-rise buildings deserves careful investigation for the appropriate assessment of the design wind loads. A synchronized incident wind and pressure data acquisition system was set up on the full-scale experimental building at Texas Tech Univ. Experiments were conducted systematically to simultaneously collect the incident wind and roof-corner pressure data under the influence of cornering winds. By using a conditional sampling technique, a bivariate quasi-steady model was established to incorporate the influence of both horizontal and vertical wind directional variations on the roof-corner pressures. Comparison between the measured pressures and the model-predicted pressures has shown that the quasi-steady theory in the suggested form is applicable in the roof-corner separated flow region where vortices are present. This conclusion further justifies the application and codification of quasi-steady approach for wind load assessment of low-rise buildings and other structures.     

Numerical/Experimental Correlation of a Plasma Wind Tunnel Test on a UHTC-Made Nose Cap of a Reentry Vehicle

The nose cap demonstrator named Nose_2 has been tested for the second time in the plasma wind tunnel (PWT) facility which is part of the sharp hot structure (SHS) technology project, focused on the assessment of the applicability of ultrahigh temperature ceramics (UHTC) to the fabrication of high performance vehicles and SHS for reusable launch vehicles. In this paper the FEM based thermal analyses, carried out for the rebuilding of this PWT test, are presented. Experimental data measured in the PWT have been compared with numerical ones in order to validate the FEM model and to help in interpreting the experimental test itself. The knowledge on the physical phenomenon under investigation has been greatly improved, thanks to the synergy between numerical and experimental activities. In particular, a qualitative study of the modeling of the tip-dome interface has been performed in order to estimate the thermal contact resistance that heat flux encounters in passing through the demonstrator. The correlation between numerical and experimental temperature curves has been found to be satisfactory for both internal and surface temperature distribution, and the FEM model was found reliable in reproducing the thermal behavior of the nose cap.     

Mathematical Model for Design of Mass Dampers for Wind Excited Structures

A state space linear mathematical model oriented to the design of passive and active mass dampers for tall buildings and bridges subjected to the wind action is presented in this paper. The model accounts for an arbitrary number of passive and/or active damping devices positioned at arbitrary points of the structure, as well as for an arbitrary number of structural modes of vibration. The aerodynamic terms of the stiffness and damping matrices are considered following a linearized quasisteady approach. A general discussion on the application of H2/H∞ control techniques to the synthesis of the active mass dampers control law is carried out. For the tuning of the mechanical parameters of passive devices, the problem is reformulated in terms of a decentralized static output feedback control law design problem.     

烧结终点控制模型及试验分析

结合马钢300 m2烧结机的控制问题,分析了烧结质量与烧结终点的关系和烧结终点与风箱坐标的位置,提出了前馈-反馈控制方法,研制出适用本设备的烧结终点位置模糊控制模型,用于适时调节烧结机的速度,进行了大量的正常工况和异常工况中欠烧、过烧情形下的试验,证明实施模糊控制后,烧结终点位置精度得到明显改善,总体改善程度约为55%,提高了烧结矿质量.该方法可用于同类型设备的控制中.