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As part of an effort to characterize the uncertainties associated with temperature measurements in fire environments, models of bare bead, single-shielded aspirated, and double-shielded aspirated thermocouples were developed and used to study the effects of varying the gas and average effective surroundings temperatures on the thermocouple error of each configuration. The models were developed for steady-state conditions and hence provide information about error trends rather than about absolute error values. The models indicate that thermocouples respond differently to changes in effective surroundings temperature in a hot upper-layer than in a relatively cooler lower layer of a room fire. In an upper-layer, for a given gas temperature, the thermocouple error is relatively insensitive to surroundings temperature. In a lower layer, errors which increase rapidly with surroundings temperature are possible. The most extreme errors occur in a lower layer when the gas temperature is low and the surroundings temperature is high. Aspirated thermocouples reduce the errors in both the upper and lower layers of a room fire, but do not eliminate them entirely. The present study is intended to provide fire researchers with a methodology for developing working models of thermocouples which are tailored to their own configurations. 相似文献
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C. Stuart Kelley 《Fire Technology》1971,7(2):101-108
Series-linked thermocouples can be used to average random heat fluctuations in flames and to reduce the amount of input data
necessary to evaluate flame temperatures. Techniques that allow computation of average temperature are described and evaluated
both theoretically and experimentally. 相似文献
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分析烟气蔓延过程中的受力,以双岛式站台为例分析烟气运动情况,根据烟气分布对探测器布局进行合理布置.设置火源功率为2 MW,以FDS模拟烟气运动.选用吸气式探测器类型为FCS-320-TM,采用Ⅰ型管道布置形式,采样孔孔径从远端依次为6.8、5.0、4.2、3.4、3.0 mm. 相似文献
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通过与其他建筑类型的比较,对风景园林建筑的内涵与关系,建筑功能、建筑技术、建筑艺术、建筑设计方面的特点做了初步探讨,并总结了风景园林建筑在构思立意,选址布局,体量造型方面的特点。 相似文献
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分级用来确定单独设计和制造起重机和/或其零部件的使用条件,也用于说明为批量生产而设计的起重机和/或其零部件的使用条件。其与疲劳验算、零部件安全系数或工作系数的选择密切相关。关于起重机的分级,有两种不同的方式。1两种分级方式的总体比较(1)以GB/T3811-2008为代表的分级,包括:GB/T3811-2008《起重机设计规 相似文献
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本文就GPS与GLONASS在卫星系统、坐标框架、时间基准、卫星坐标计算和模糊度的求解等方面的差异进行了比较分析,并得出了一些有益的结论。 相似文献
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随着社会物质文化水平和社会审美水平的不断提高,竖向构件作为一种整合建筑立面,成为设计师的提升外观整体性的一种常用设计手法。本文从目前常用的竖向构件的自重、造价以及立面效果等方面对其进行评价、比较,希望能对相关的建筑设计提供一些帮助。 相似文献
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In order to cumpare the peformance of different supply diffuers of ventilation air, the airflow passern, temperature stratifiation and contaminant dispersion in a furnitured office ventilated by three kinds of air diffuer were numerically investigated. The air diffuers studied in this paper are a quarter-cylinder displacement diffuer on the floor and mixing diffuers (linear and vortex diffuers) on the ceiling. The heat sources in the of-fice are considered to be 50% convective and 50% radiative. The k-? two-equatwn model of turbulence is employed to predict the turbulent diffusion. The results show that the displacement diffuser provides a rather uniform flow field with low velocify in most areas, and the vertical temperature difference from floor to ceiling is as high as 6 K. With the linear diffuser, the air velociry is high, and the temperature is uniform both horizontally and vertically. The air velocity generated by the vortex diffuser is moderate. The distributions of the temperature and the contaminant are rather uniform. 相似文献
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建筑环境评估体系及比较 总被引:11,自引:0,他引:11
进入新世纪以来,可持续发展在世界范围内成为一个更加严峻的话题,为了更有效地控制和利用我们的环境资源,许多国家纷纷制定了相关的建筑环境评估体系。本文介绍了当今四个具影响力的环境评估体系,包括英国的 BREEAM体系,美国的 L E E DTM 系统,澳大利亚的NABERS以及中国的 GBCAS。通过对比阐述了四个体系不同的发展历程、内容、权重及特别之处。 相似文献
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通过介绍西方发达国家的招投标模式,并与中国的招投标制度进行对比,分析当前我国招投标制度所存在的问题和差距,并以此提出改进的建议。 相似文献
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杨婧文 《建筑热能通风空调》2011,30(6):98-100,94
本文结合地源热泵应用于办公建筑的具体工程实例,提出了地源热泵经济性、节能性的评价指标和分析原则,通过与其他形式的供暖(冷)系统的对比,进行了具体的方案设计、经济性和节能性的分析,提出了最终的优化方案。 相似文献