船用钢板移动电磁感应加热温度及变形特性

采用带间隙双回路反向电流(ODIG)感应器作为热源,基于ANSYS多物理场耦合数值模拟方法,结合感应器及周围空气动态移动方法,建立移动式电磁-热交互耦合数值模拟模型。将获得的瞬态温度作为载荷,进行热-弹塑性数值分析,研究船用钢板移动电磁感应加热温度分布和变形分布。分析不同工艺参数(感应器与钢板间隙g、钢板厚度H、电流频率F、电流峰值I_(peak)和移动速度v)对热成形(最高温度T_(um)、宽度b和厚度h)和变形(横向收缩δ_z和横向角变形θ_z)特性的影响。结果表明:温度云图为带预热的双椭圆外形;影响热成形特性的主要因素为I_(peak)、v和g;影响变形最主要的因素是I_(peak)和H。     

带支撑梁的船闸闸室裂缝成因分析

针对某船闸闸室施工期在支撑梁上部出现表面裂缝的问题,基于有限元原理,分析闸室表面裂缝的成因及分布规律,并提出防止表面裂缝产生的温控措施.分析结果表明:早期在支撑梁上部出现表面裂缝主要是因为内外温差以及支撑梁对新浇筑混凝土的约束作用;在控制浇筑温度的基础上,采取表面保温和内部水管冷却相结合的温控措施,可以将表面点的抗裂安全系数提高至1. 40.该方案在后续施工应用后未出现表面裂缝,达到了良好的防裂效果.     

蜂巢式液冷电池模块传热特性的试验研究

为4 A·h的21700型锂离子电池研发了蜂巢式液冷电池模块,并通过搭建的试验平台测定其充/放电过程的传热特性。结果表明:在25℃环境温度下,0.5C恒流恒压充电和1C恒流放电过程中,电池模块的最大温差均被控制在2℃以内;40℃环境温度下,1C恒流放电过程中,当冷却液流量大于1 L/min时电池模块的最大温差能保持在所要求的5℃以内。说明蜂巢式液冷电池模块冷却性能优良,可为未来电池热管理方案的设计提供技术支撑。     

浮置板式轨道结构隔振效果仿真研究

建立列车—轨道结构耦合系统有限元模型,将轨道不平顺作为列车—轨道结构耦合系统的激励源,对普通碎石道床轨道结构和浮置板式轨道结构的列车—轨道结构耦合系统动力学性能进行仿真研究,对比分析这2种类型的轨道结构系统振动响应与系统振动传递函数,评价浮置板式轨道结构的隔振效果。分析结果表明,浮置板式轨道结构与普通碎石道床轨道结构相比,振动加速度降低约70%,距线路5 m处大地振动加速度响应峰值降低约62.8%,相应Z振级衰减约10 dB,竖向振动加速度频率范围由0~200 Hz降到0~60 Hz,有效起到了振动隔离效果。     

接触网导线热过负荷保护的探讨

针对电气化铁道运行现状和铁路运输情况的变化,分析了目前电气化牵引变电所馈电线继电保护设置存在的不足,阐述了设置接触网导线热过负荷保护的必要性和保护原理,并结合国外过负荷保护装置的情况,提出了我国电气化铁道接触网导线热过负荷保护方案。     

Phase change analysis of an underwater glider propelled by the ocean＇s thermal energy

The phase change characteristic of the power source of an underwater glider propelled by the ocean＇s thermal energy is the key factor in glider attitude control. A numerical model has been established based on the enthalpy method to analyze the phase change heat transfer process under convective boundary conditions. Phase change is not an isothermal process, but one that occurs at a range of temperature. The total melting time of the material is very sensitive to the surrounding temperature. When the temperature of the surroundings decreases 8 degrees, the total melting time increases 1.8 times. But variations in surrounding temperature have little effect on the initial temperature of phase change, and the slope of the temperature time history curve remains the same. However, the temperature at which phase change is completed decreases significantly. Our research shows that the phase change process is also affected by container size, boundary conditions, and the power source＇s cross sectional area. Materials stored in 3 cylindrical containers with a diameter of 38ram needed the shortest phase change time. Our conclusions should be helpful in effective design of underwater glider power systems.     

Prediction of thermal environment via revision of PMV index with body temperature

PMV （Predicted Mean Vote） is a widely used index for evaluating the thermal environment. However, few studies have been conducted to take physiological values directly as evaluating indices. This paper assumes a linear relation between body temperature and both sweating rate and heat produced by shivering, and introduces the linear relation into the human heat balance equation to revise the classic PMV. And the assumption of linear relation is subsequently proved. The revised PMV possesses the same characteristic of dependent heat load as that of the classic one, and moreover it is convenient to be calculated.     

暗挖双连拱隧道穿越浅基础高层楼群区施工技术

北京城市铁路东直门区间采用双连拱隧道结构形式 ,在富水松散地层中从两栋浅基础高层居民楼中间采用浅埋暗挖法通过 ,施工难度极大。本文主要阐述针对该段复杂的施工边界及约束条件 ,在处理地层与结构、隧道施工与既有建筑物相互作用 ,所采用的技术方法和特殊条件下的高层建筑防护技术 ,以及监测在施工中的应用 ,以期为今后类似工程的施工提供参考和借鉴。     

牵引电机防寒技术探讨

提出了寒冷环境下牵引电机需考虑的关键部件,分析了寒冷环境对牵引电机关键部件的危害性影响,并逐一提出了防寒措施。     

寒冷地区客车的防寒设计

根据25T型铁路客车在寒冷地区的运用,分析了列车防寒的主要因素,包括车体的密封性、防寒材料的薄弱部位和热绝缘等。结合运用结果,提出了寒冷地区列车防寒结构方案的改进设计。