长大列车空气管系充气特性数值仿真研究

应用现代流体动力学数值计算方法,以长大货物列车空气制动管系的充气特性作为研究对象,研究列车编组辆数、管系组成、管系泄漏等因素对列车管充气压力的影响和沿列车管长度方向的充气压力分布情况。建立了考虑列车管泄漏的连续性方程,给出一种求解压力速度耦合方程的显式有限差分算法。将计算结果和国内外长大列车充气特性的有关试验数据进行对比分析。研究工作为长大列车制动作用的试验研究提供理论参考,并为研制完整的货物列车空气制动系统奠定了基础。     

昆仑山隧道渗漏水原因探讨及治理

通过现场连通试验,对青藏线昆仑山隧道渗漏水的水源、流径进行了试验研究。结果证明,造成渗漏水的主要原因是隧道结构周围存在融化圈,解冻后使衬砌外侧积聚承压水,在寒季冻结又产生巨大冻胀力,对隧道混凝土结构及防水板接缝产生破坏,形成出水通道;而且排水系统只能季节性排水。提出二号冲沟采取截、排、降,及延长冲沟地表帷幕注浆的范围,洞内水沟采暖,洞内回填注浆的治理方案。借助地质雷达等手段进行效果检测表明,治理达到了预期效果。     

中小型船舶长效艉轴密封装置的研究与设计

通过对现今多种常见的船舶艉轴密封装置进行分析研究后,设计了一种适用于中小型船舶的有效期长的自动递补式艉轴密封装置,并介绍这种新装置的结构和原理。     

防止铝合金减震器筒体渗漏的铸造工艺措施

减少铝液中的含气量、减少缩松倾向的工艺措施、使用金属型加强排气是防止减震器筒体渗漏缺陷的几种铸造工艺措施,经过生产实际验证后效果良好。除了采用在型腔内安放预置金属型芯会增加型芯制造及安放工时外,其它措施均方便可行,这些铸造工艺措施对减震器筒体及其它铝合金铸件的生产有一定的参考价值。     

UM71（ZPW-2000A）型无绝缘移频轨道电路电气绝缘节窜码原因分析

阐述四端网络的基本计算方法,根据无绝缘轨道电路电气绝缘节的绝缘机理,对窜码的必然性进行了定性分析,并通过四端T型网络计算进行定量分析。     

Ultrafine particle infiltration into passenger vehicles. Part I: Experimental evidence

Previous studies have reported ultrafine particle (UFP) infiltration to the in-cabin microenvironment; however, no systematic measurements have been conducted showing where and under what conditions infiltration occurs. This study examined the automotive envelope leakage and UFP infiltration. We measured the differential pressures between the cabin and the potential leakage area on the surface of 11 passenger vehicles of different models/makers. To identify location of infiltration, UFP concentrations were concurrently measured inside and outside the vehicles as well as near the rear trunks. This study found that UFP infiltration primarily occurs through the rear trunk leakage under recirculation (RC) mode. Under RC mode, aerodynamic effects of a moving vehicle made the surface pressure on the side doors lower (i.e., exfiltration) than the cabin pressure, but higher (i.e., infiltration) on the rear trunk. The UFP concentrations measured near the rear trunks were 2–9 folds higher than inside vehicles. The magnitude of pressure differences increased at higher driving speeds. Under outdoor air (OA) mode, the infiltration was rarely observed because of the fan-controlled cabin pressurization. These data provide the first experimental evidence showing that UFP infiltration into passenger vehicles is location-specific and driving-speed-dependent.     

港口起重机钢丝绳失效过程中的磁化性质研究

基于起重机钢丝绳滑轮疲劳试验台,运用钢丝绳的磁检测技术,研究了钢丝绳周向漏磁场强度随疲劳循环次数的变化规律,发现随着疲劳程度的增加,钢丝绳周向漏磁场强度逐渐增大,磁导率逐渐减小,且沿钢丝绳轴向长度的分布越来越不均匀.研究表明,可以通过分析磁化性质的变化判断钢丝绳的疲劳程度.     

Investigation of the effectiveness of tandem oil fences under currents

The behavior of the flow passing a tandem oil fence, and the performance of the fence, were investigated by experimental and numerical methods. The flow characteristics between tandem fences were measured by the particle image velocimetry (PIV) method for the rigid and open free surface between the two fences in order to gather reference data for numerical investigations. A method of assessing a tandem fence by tracing the movement of an oil droplet around the fence is introduced. The effect of the current speed, the separation distance between the two fences, the relative draft of the two fences, and the water depth on the oil containment between the fences was investigated.     

某型 SUV 白车身气密性分析及优化

文章通过对某运动型多用途汽车（SUV）进行整车和白车身（BIW）的气密性测试,运用了 LeakageMaster 泄露路径仿真分析软件对该车型白车身进行仿真分析,找出了该车型白车身的主要泄漏点。然后结合了白车身烟雾试验的结果,对白车身的主要泄露点制定相关的密封措施,最终使该车型白车身气密性达到目标要求,提升了整车噪声、振动与声振粗糙度（NVH）的性能,从而提升乘客乘坐舒适性。     

GB125摩托车离合器操纵杆油封渗漏整治

根据油封密封机理,对油封与O形圈密封的差别、安装孔对油封密封的影响及油封的安装等方面进行了研究,对CB125离合器操纵杆油封渗漏油问题进行了全面分析,最后采用在原安装孔底平面加工一直径φ18 mm、深0.5 mm的台阶,同时仍装用原结构油封的方法,简便、易行,取得了理想效果.