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51.
52.
V/X接线牵引变压器的温升特性 总被引:1,自引:0,他引:1
针对V/X接线牵引变压器独特的接线方式、电气特性和负载特性,基于热电类比原理和变压器内部热传递过程建立V/X接线牵引变压器内部热路模型.参照电路理论推导温升计算微分方程,并根据热特征参量问的相互关系,建立V/X接线牵引变压器内部温升计算模型.以1台机车从驶入到驶出某V/X接线牵引变压器供电区间的过程为例,仿真计算顶层油温度曲线和绕组热点温度曲线.分析绕组绝缘寿命的影响因素,并根据牵引负荷的特点,提出适用于V/X接线牵引变压器的绝缘寿命损失计算方法. 相似文献
53.
杨乐明 《铁道标准设计通讯》2015,(3):46-49
为了研究CRTSⅢ板式无砟轨道在施工过程中精调装置拆除的最优时间,采用有限元方法建立单元板式无砟轨道的实体模型,通过考虑精调爪的安装数量以及不同地区存在的温度梯度的差异情况,进行其最优安装数目及拆除时间的研究。计算结果表明:精调爪数目为4组时可最有效地减小轨道板的翘曲变形;在温暖地区,当自密实混凝土强度达到35%之后可拆除精调爪;在寒冷地区,当自密实混凝土强度达到45%之后可拆除精调爪;在严寒地区,当自密实混凝土强度达到50%之后可拆除精调爪。由此可最大限度地加快施工进度且不影响轨道施工质量。 相似文献
54.
ABSTRACT In this paper we focus on the estimation of crowding in public transport – specifically urban rail systems – and its effect on perceived comfort. It is different from similar studies in the method it employs for estimating crowding levels in vehicles. Specifically, we formulate a function of time and location, which uses only passenger embarking data to estimate the number of passengers in vehicles. Then we convert the estimated crowding values into perceived discomfort levels by trip section. Our method depends on hourly seasonality assumptions but provides good estimates of crowding in urban rail systems even when passenger alighting data is not available. We illustrate the implementation of our model with the example of the Istanbul Metro system. 相似文献
55.
Hot weather events, ventilation assets, changing passenger demand and service expectations have all caused increased attention on thermal comfort on London’s Tube. This study provides estimates of the future number of days when passengers travelling on sections of the Tube could be subjected to thermal discomfort under future scenarios of climate change, and the potential number of passengers dissatisfied. A risk based methodology is presented, integrating a spatial weather generator modified for urban areas and a thermal comfort model. The study provides an initial assessment of adaptation options by considering the implications of lowering train temperatures by 2 °C and 4 °C to represent saloon cooling. Median results under a 2050 high scenario indicate that all Tube lines assessed could experience near-complete passenger dissatisfaction with the thermal environment in trains in the unlikely event that nothing else were to change. Adaptation aimed at lowering train temperatures has the potential to provide tangible improvements in thermal comfort. However, this was not projected to be sufficient to maintain comfortable thermal conditions for many of the lines in the 2050s under high emission scenarios, requiring a combination of other infrastructure cooling measures to be implemented in parallel. 相似文献
56.
基于Sandra Schwanitz等人采用连续性评估方法所做的实车试验和压力舱试验,介绍了试验方法、试验结果、两种试验条件下结果的差异以及采用广义估计方程模型分析压力变化特性对不舒适性的影响,总结了连续性评估方法的特点及适用性.期望为相关研究人员的研究工作以及工程设计师在高速列车及隧道设计方面提供参考. 相似文献
57.
张慧慧 《辽宁省交通高等专科学校学报》2013,(6):20-22
目前,大型石质文物亟需一种新型无损检测技术来现场检测其病害情况。本文通过物理模拟方法,应用红外热成像无损检测技术对太阳照射下不同湿度岩石的热像变化特征作了实验研究,验证了应用红外热成像技术检测石质文物渗水病害的可行性。 相似文献
58.
Gang Fan Yihong Guan Jiatao Zhang Honggang Wang Kunming University of Science Technology Kunming China 《上海交通大学学报(英文版)》2000,(1)
IntroductionLaserphasetransformationhardeningisanewtechnologyduringwhichlaserheatresourceactsdirectlyonsurfaceofmaterialandcompositionscharacteristicofmaterialischanged.Thetechnologyproce8sesacharacterofrapidheatvelocity,highheattempelatureandquickcoolingspeed(l0'col0'aC/s).Thecompositionandcharacteristicofmaterialvariedwithvariousinnertemperaturewillleadtothermalresidualstress.Itiswellknownthattheresidualstressaffectssignificantlyoncharacteristicofmaterial,suchasimProvingstrengthoffatigUere… 相似文献
59.
随着新能源汽车热管理行业的迅猛发展,整体竞争格局形成了两大阵营。一类是以综合性热管理方案为主的国际巨头,另一类是以专一性热管理产品为代表的国内主流热管理零部件企业。并且随着电气化升级,热管理领域新生零部件迎来了增量市场,在新能源汽车新增的电池冷却、热泵系统以及其他电气化升级带动下,热管理方案中运用的部分零部件种类随之发生变化。本文主要通过对新能源热管理领域竞争格局以及核心部件的技术发展分析,对电池热管理、整车空调系统、电驱动及电子元器件等关键技术部件进行了详细综述与分析,并对新能源汽车热管理行业技术发展趋势进行了综合预判。 相似文献
60.
Chang Doo Jang Tae Hoon Kim Dae Eun Ko Thomas Lamb Yun Sok Ha 《Journal of Marine Science and Technology》2005,10(4):211-216
In a shipyard, line heating and triangle heating are two major processes carried out by skilled workers to form curved plates
in various shapes under various heating conditions. There have been many studies on line heating, but triangle heating has
rarely been studied owing to its complicated heating process with irregular multiheating paths and highly concentrated heat
input. Triangle heating is the most labor-intensive job. Hence, it is essential for most shipyards to study the automation,
as well as the improvement, of the triangle heating process in order to increase hull-forming productivity. In this study,
a pioneering attempt to simulate triangle heating was made. A circular disk-spring model is proposed as an analysis model
for the elastoplastic procedure of triangle heating, and the inherent strain method is also used to analyze the deformation
of plates. The results of the simulation were compared with those of experiments and showed good agreement. It is shown that
the present approach and the model used in this study are effective and efficient for simulating triangle heating for the
steel plate forming process in shipbuilding. 相似文献