舰船燃气和蒸汽动力装置的发展与展望

通过二个典型机型及其有关资料的介绍,论述了舰船燃气及蒸汽动力装置的现状与发展趋势。     

重庆康明斯柴油机机油的正确使用

论述了重庆－康明斯柴油发动机工作特点，以及该发动机对润滑油的要求，该发动机要求使用重庆康明期专用机油－１５Ｗ／４０ＣＤ级柴机油机油。最后对如何正确使用润滑提出了一些看法。     

10万m3原油储罐罐底内底板腐蚀与牺牲阳极阴极保护

叙述了原油罐内的腐蚀状况与腐蚀机理 ,并介绍了大连某海港 10万m3原油储罐罐底内板涂料防腐和牺牲阳极联合保护对策及应用情况。结果表明 :原油罐底板内壁阴极保护后 ,保护电位均低于 - 0 85V(Cu/CuSO4 )。说明原油罐底板内壁实施牺牲阳极保护后 ,阴极保护系统稳定 ,牺牲阳极保持较低的工作电位 ,使原油罐底板内壁得到完全保护 ,达到了设计技术指标     

WY125系列摩托车后减震器漏油问题的分析及改进

摩托车后减震器渗漏油问题,除受本身设计、部品结构及总成的耐久性能影响外,还受行驶道路、交通情况等因素影响。减震器中的关键零部件油封,其胶料、结构尺寸及相关部件的接触表面粗糙度和尺寸对漏油影响较大,而且过载使弹簧弯曲对油封单边磨损也会引起渗漏。     

The overall effects of road works on global warming gas emissions

Road characteristics influence the amount of pollution generated by traffic. They govern the rolling resistance, which includes: the viscoelastic behaviour of the pavement structure, surface texture, and profile unevenness. Road works are performed on a periodic basis to maintain these characteristics at proper levels of service (e.g. safety, comfort, and noise). While such works produce additional pollution (due to congestion around worksites or extra fuel consumption along the detour route), they still result in less pollution over the long term. This article assesses the balance between an increase in gas emissions during road works and the reduction in emissions from traffic once the works are completed. It is demonstrated that when road works are introduced to correct longitudinal profiles, rather than texture, the emissions benefit is substantial.     

Computing airfare elasticities or opening Pandora's box

Airfare elasticities are crucial for policy instruments for the stakeholders of tourism industry. Modellers attempting to estimate these elasticities face several challenges in the absence of microeconomic data on consumer preferences. The aim of this paper is to offer a critical analysis of the practice of computing airfare elasticities from tourism demand studies. It identifies and discusses potential sources of measurement errors in the data and drawbacks that investigators face and assesses their implications for the estimated parameters in the respective models. The use of price of crude oil and distance between origin and destination as proxies for transportation costs are evaluated. It is recommended that authors be more systematic in reporting their results. They need to comment on the limitations of their elasticity estimates since these have repercussions on policy recommendations made based on their results.     

汽油发动机倾斜试验研究

发动机倾斜试验的目的是验证润滑系统和曲轴箱通风系统在前后纵倾、左右侧倾及两者相结合时的状态是否符合要求,并对这几种情况进行单独分析及合成分析。文章以三缸汽油发动机为例介绍试验目的、试验准备、仪器和设备、试验方法、数据结果分析等。试验通过倾斜发动机至一定角度模拟整车在加速、转弯、刹车时油底壳液面高度及角度,评估发动机的润滑系统和曲轴箱通风系统在类似的整车工况下是否满足发动机的正常工作需求,为发动机的设计及验证提供参考。     

隧道盾构施工对邻近管线群位移影响的模型试验研究

隧道盾构施工会对邻近管线造成不利影响,但目前对管线位移的研究多集中在单一管线方面,考虑管线之间影响的研究较少。针对这一问题,开展砂土地层盾构施工对邻近管线群影响的室内模型试验,研究隧道盾构垂直下穿多条既有管线时对管线竖向沉降的影响。研究结果表明:当单一管线垂直于隧道开挖方向时,管线最大沉降发生在隧道正上方位置,沉降曲线形态关于隧道轴线呈对称分布,且符合Gauss曲线特征;当隧道垂直下穿双管线时,管线产生的竖向沉降曲线形态与单一管线基本一致,但管线最大沉降值较单一管线明显减小。通过对试验结果的归一化分析,提出管线间距对最大沉降影响的计算公式。     

Large deformation coupled analysis of embedded pipeline – Soil lateral interaction

Subsea pipelines buried in the seabed may undergo large lateral displacement under environmental, operational, and accidental loads at different interaction rates and hence different drainage conditions. The undrained shear strength is commonly used in practice to assess the pipe-soil interaction assuming a sufficiently high displacement rate. This approach neglects consolidation effects and the rate-dependent response of the soil and may significantly underestimates the lateral resistance for a pipeline moving slowly relative to the ground. In this study, a coupled large deformation finite element (LDFE) framework is developed via a remeshing and interpolation technique with small strain (RITSS). A Modified Cam-Clay (MCC) model with efficient numerical integration is used. The proposed coupled LDFE framework is verified against selected physical model tests. Effects of the interaction rate and hence drainage condition on the p-y curve, excess pore pressure generation and dissipation, and failure mechanisms are discussed. An empirical relationship between the ultimate resistance and the normalized velocity of the pipe (denoting the drainage condition) is proposed, which may be applied for the integrity and safety analysis of buried pipes in landslide or fault-crossing regions.     

船舶燃气轮机装置分布式集成仿真平台设计

针对船舶燃气轮机装置分布式集成仿真的功能,设计了包括应用层、支撑层、通讯层和设备层在内的分布式集成仿真平台体系层次。选择 MATLAB/SIMULINK环境开发应用层和支撑层,选择HLA协议和RTI软件实现通讯层。最终形成了由平台运行管理器、分布式仿真包、模块化模型库、分布式仿真接口以及RTI软件组成的“服务器/运算节点”式的平台运行框架。通过某型双轴燃气轮机在机械推进工作方式下的分布式集成仿真实验,初步验证了平台体系框架的合理性和有效性。