智慧城市中的风设计

随着城市密度变大,越来越多高层建筑的出现导致了步行高度上风速的增加,降低了行人舒适感和整个社区环境的吸引力。城市内的平均气温同样随着城市密度的增加而升高,难以降低的温度导致死亡率的提升。可以通过增强街道通风和散热等方式给城市降温,从而缓解这类问题。Actiflow对政府部门的建议为:1)在评估风对所在城市的影响时,须同时考虑其他因素;2)确定城市中的关键区域,设想如何应对其所面临的挑战;3)确定需要达到的品质标准;4)将大尺度上的解决方案及品质要求转化为实际操作导则。一般来说,城市环境下的风参数评估技术有3种:实景测量、风洞实验和CFD计算机模拟(也称CFD或计算机流体力学)。对于城市中完整的风参数评估来说,实景测量并不是最佳选择,而CFD与风洞实验相比的主要优点为:1)能将整个风场可视化,而不仅是安装了传感器的离散点;2)即使是阳台或其他私人区域周边细微的空气流动都可被研究。CFD的最大缺点在于当模拟风的动态特征发生时(例如狂风等情况),就会由于计算量太大而变得非常困难。荷兰NEN8100标准描述了2种评估步行环境风舒适度的方法:风洞实验以及CFD计算机模拟。Actiflow基于这项标准在风参数评估领域积累了相当丰富的经验,其中一个案例便是阿姆斯特丹附近的Amstel Ⅲ区域。Actiflow向市政府提供了在公共场所缓解风障碍和危险的可行措施,并为该地区的房地产开发商们制定了详细的导则。

WLB2500井下水力涡轮力学特性台架试验及CFD模拟

通过对WLB2500井下水力涡轮的室内试验,得到了涡轮的力学特性曲线,并以此为依据,研究了涡轮的CFD模拟方法,探讨了CFD计算在涡轮设计中的有效性。结果表明,所采用的CFD全流道模型可以解决以往单跨流道模型忽略了容积损失的问题,所预测的涡轮力学性能基本与实际吻合。说明本文采用的计算方法基本合理,可用于井下水力涡轮的设计中。

小型窑炉活性炭脱硫脱硝吸附塔的设计思路

本文针对小型窑炉的特点,分析了活性炭脱硫脱硝的原理,并进行脱硫脱硝装置的设计构想,采用沸腾流化床的设计思路,计算了烟气流速、吸附塔直径、料高等各个部位的核心参数,采用CFD流体模拟,利用三大守恒公式,模拟吸附塔结构及烟气流场,通过模拟结果,对吸附结构进行调整,逐步完善并达到相对标准偏差≤15%,形成一整套的设计思路。

浅谈某办公大楼空调设计

本文总结某集团办公大楼办公室及会议中心空调设计,其中涉及10 kV水冷中央空调、多联机空调、座椅送风、洁净新风系统等空调设计,为该类建筑暖通空调系统设计提供经验参考。

“红飘带”显示屏背后腔体的通风散热方案分析

"红飘带"是国庆70周年庆典时天安门广场上一临时构筑物,其上镶嵌的6块LED大屏幕在工作过程中主要依靠背部空调室来降温。由于美观和安全性等要求,空调室外机必须安装在飘带内部仅顶部镂空、近乎封闭的空间中,其释放的热量将会积聚而难以散出。设计团队先后提出了自然通风及大风机机械排风方式将高温空气"吹"出腔体的方案,并经过不同方案的气流组织模拟、风机结构优化、专家研讨及现场实测验证等系列工作,敲定了最终方案,解决了高温气体聚集、风机的大重量支撑及运转高噪声等问题,最终顺利保障了国庆阅兵及晚会期间飘带上所有显示屏的正常运转。详细介绍了计算机数值模拟辅助通风散热方案的设计与比选过程,并给出了方案实测结果,以期为将来类似的工程提供技术参考。

Modeling the Axial Balancing Mechanism of Orbit Annular Hydraulic Machines

A customized combined methodology based on both 2D CFD （computational fluid dynamics） and lumped parameters numerical modeling, useful for simulating the hydraulic behavior of orbit annular machines, has been developed and here presented. More in details, the predictive capabilities of this CAE （computer-aided engineering） tool can be applied for the study of both roller and gerotor architectures and considering both pumping and motoring operating mode. First of all, an in-house developed 2D CFD methodology, based on the integration of the stationary form of the Reynolds equation for the determination of the pressure distribution inside the lateral clearances bounded by the sides of the stator-rotor group and the valve plate, as well as the internal manifold surface, is firstly presented and applied. The same computational procedure has been also involved for the investigation of the leakages through the clearance between the valve plate and the balancing ring. After that, a lumped and distributed parameters numerical model has been involved for the simulation of a typical orbit roller motor operation. In this case, particular care has been devoted to the modeling of the axial leakage clearances, adopting analytical interpolation functions deducted from the numerical results calculated applying the previously described 2D CFD methodology. Finally, the whole CAE approach has been validated by means of a comprehensive numerical versus experimental comparison, obtaining a general good accordance for the overall operating field of this particular type of hydraulic unit.

Development and application of simulation technique for hydrokinetic hammer

The computer simulation is an important method for hydrokinetic hammer design. Various kinds of simulation measures with their technical characters and applications being taken during the computer aided design are enumerated. Computer simulation supports plenty of valuable references to the designer. Each type of simulation process is used to explore the exact aspect of the performance of hydrokinetic hammer and each type of simulation method has its own excellences and deficiencies. Thus the integrative simulation methods based on modem computational technology are brought forward to obtain the perfect capability of the whole product. Along with the development of computer hardware and software, various kinds of platforms have been provided to different simulation methods that can be carried out with distinct working flows. The jet flow element is the core part of the hydrokinetic hammer. We can build the ideal simulation model of it by means of CFD （ computational fluid dynamics） technology. On the other hand, to set up the digital model of piston and hammer, the best way is to build the virtual prototype using automatic dynamic analysis of mechanical system. As a result of the argumentation, we think the technique of Virtual Prototype and CFD are the prime way to process the combined computer simulation for hydrokinetic hammer,

NO70燃烧系统在燃煤锅炉脱硝中的应用

介绍了NO70燃烧系统的特点以及计算机流体力学模拟原理。分析了使用NO70燃烧系统技术对旺隆电厂的2×100MW四角切圆燃煤锅炉进行改造,有效降低氮氧化物排放量并提高机组效率的案例。

大型交通枢纽上客区通风系统研究

一些大型交通枢纽换乘中心设置于高架或平台下,虽四周开敞、顶部有少量开洞,但空气品质不如人意.针对这种半室外空间情况,结合具体工程实例,对其通风系统设置提出了设计思路和方法,并采用计算机模拟进行了优化和验证.