某款增压发动机的进气系统的消声器设计开发

进气口噪声对整车NVH起着至关重要的作用,影响着驾乘人的直观驾乘感受,进而影响客户心中的整体评价。文章基于某车型进气系统声学性能优化,通过分析进气口噪声基态测试结果,建立了有针对性的消声器设计方案;而后,通过声学仿真对消声器的传递损失进行了初步分析;最后又通过整车搭载对消声器的性能进行了试验验证。结果显示,搭载消声器后的进气口噪声测试结果可以满足声学性能目标,设计过程中涉及的仿真与试验方法具有一定的参考价值。     

城市交通出行方式对能源与环境的影响

社会经济的快速增长使得人们的出行日益频繁,从而导致城市机动车保有量迅速增加和能源需求及其大气污染排放不断上升。本文以上海为例,应用LEAP模型,研究了在确保交通需求增长的前提下,发展不同的交通出行方式对能源需求和大气污染物排放的影响。结果表明,调整上海市交通发展模式,即有序发展私人交通、大力发展公共交通对于减少全市道路交通能源需求,减缓供应压力,降低大气污染排放具有重要意义。     

Impact of Visible-Solar-Light-Driven photocatalytic pavement on air quality improvement

Photocatalytic pavement has attracted significant interest in the past decades by both the academia and industry for its ability of spontaneous cleaning of air pollutants, such as motor vehicle exhaust gas. Titanium dioxide (TiO₂) is used as the photocatalyst that is mixed into pavement materials or coated on the pavement to remove motor vehicle exhaust gases, e.g., carbon monoxide (CO), nitrogen oxides (NO_x), under the irradiation of the solar light. However, the pure TiO₂ additive only absorbs the light within the ultraviolet region due to its large bandgap. One approach to increase the ability of TiO₂ to the utilization of the full spectrum of the solar light is doping TiO₂. Therefore, this visible-solar-light-driven photocatalytic pavement embedded with doped-TiO₂ will exhibits a better cleaning efficiency of exhaust gas. This work conducted computational simulations of the cleaning efficiency on reducing exhaust gas NO₂ by photocatalytic pavement with doped-TiO₂, and its subsequent influence on the air quality in the surrounding environment. A three-dimensional model was developed for a section of pavement and its vicinal region. Effects of weather conditions, doped-TiO₂ coverages, road widths and traffic flow conditions on the removal of NO₂ and its influence to the adjacent environment were studied. Results indicate that visible-solar-light-driven photocatalytic pavement with doped-TiO₂ features a significantly higher removal efficiency of exhaust gas compared with the normal photocatalytic pavement. Moreover, the doped-TiO₂ embedded pavement is effective to remove NO₂ with different traffic densities and wind conditions, and consequently improve the air quality of the surrounding environment.     

车辆制动系统螺杆空压机组润滑油防乳化控制方法

在城市轨道交通车辆调试与运营前期,由于车辆制动系统中的螺杆空压机组运转率较低,导致空压机组中的润滑油容易发生乳化现象。为此,通过防乳化控制方法,使空压机组在每次车辆上电时先连续运转30 min,用于提高润滑油温度,加速润滑油中水分的汽化,避免润滑油乳化现象,提高润滑油使用寿命。     

Investigation of environmental justice analysis in airport planning practice from 2000 to 2010

Municipal airport owners and the Federal Aviation Administration (FAA) regularly evaluate capacity and demand to decide if and when airports need more infrastructure. New infrastructure can alter the profile of noise, emissions, and land use, which may affect the quality of life for airport-adjacent communities. When the FAA and airport owners initiate infrastructure expansion, they must conduct environmental justice analysis to measure the distribution of negative externalities on nearby communities. This research investigates the environmental justice methodologies and narratives reported in planning documents for nineteen airport capacity expansions planned or deployed from 2000 to 2010 in the United States. The mixed-methods approach analyzes airport operations data, spatial demographic data, and planning artifacts to determine whether the environmental justice analyses were robust. This research proposes alternative metrics, the ‘Risk of disproportionate impact’ and ‘Capacity strain’, to further contextualize the presence of protected population groups alongside capacity needs. The main finding of the study is that the planning documents did not consistently detect environmental justice impacts, nor did they consistently confer importance to those impacts when high proportions of protected populations were detected. As a result, the social costs of collective airport expansion are unclear and likely underestimated. This study identifies two limitations that undermined the environmental justice analysis throughout the airport sample: (1) inconsistent methodological choices impeded the detection of impacts and, (2) narrative interpretations tended to ‘null’ the finding even when impacts were detected.     

半潜式支持平台恶劣海况下运动性能试验研究

半潜式支持平台的研发面临一系列技术难题，尤其是恶劣海洋环境对平台的影响。恶劣环境下，平台会出现严重的非线性载荷特性，严重时会危害平台安全，因此在研发设计阶段，有必要开展半潜式支持平台在恶劣海洋环境下的运动性能研究。针对我国自主开发设计的某型深水半潜式支持平台，基于模型试验方法开展恶劣海况下运动性能研究。在完成水平系泊系统和气隙、砰击载荷测试方案设计的基础上，开展试验研究，获得了平台固有周期、阻尼系数、恶劣海况下的运动响应以及气隙、砰击等非线性载荷。结果显示，在恶劣海况下，目标平台运动响应较大，不具备作业条件。平台多处气隙出现负值且发生较为显著的砰击现象，砰击次数及砰击压力均较大。结果为半潜式支持平台总体设计提供了有效的支撑数据。     

基于单轮对试验台的高速制动防滑试验研究

利用高速轮轨关系试验台,接入制动气路设备,建立试验台与制动防滑器间的信号和指令传递,进行高速制动防滑试验。首先,采用电惯量模拟的方式,实现制动条件下试验台轨道轮的运动惯量与实车试验车辆轴重的运动惯量一致,通过控制轨道轮的圆周速度,使试验台试验车速与实车试验车速保持一致,并将其作为防滑控制系统的参考速度;然后,依据试验台制动防滑试验流程,通过干燥条件下的纯空气紧急制动试验结果对试验方法的可靠性进行验证;在此基础上,试验某动车组制动防滑器在200和300 km·h^-1制动初速度及在喷水和喷防冻液条件下的制动防滑特性。结果表明:干燥条件下的纯空气紧急制动试验,实际减速度与目标减速度基本吻合,试验台试验的制动距离较实车试验的相对误差满足标准要求,试验方法可靠;喷水条件下,制动初速度为200 km·h^-1时初始滑行阶段的制动率更高,而喷防冻液条件下,制动初速度为300 km·h^-1时初始滑行阶段的制动率更高;喷防冻液条件下的轮轨黏着利用比喷水条件下更充分,制动率更高,制动距离更短。     

Modelling the resilience,friability and costs of an air transport network affected by a large-scale disruptive event

This paper deals with developing a methodology for estimating the resilience, friability, and costs of an air transport network affected by a large-scale disruptive event. The network consists of airports and airspace/air routes between them where airlines operate their flights. Resilience is considered as the ability of the network to neutralize the impacts of disruptive event(s). Friability implies reducing the network’s existing resilience due to removing particular nodes/airports and/or links/air routes, and consequently cancelling the affected airline flights. The costs imply additional expenses imposed on airports, airlines, and air passengers as the potentially most affected actors/stakeholders due to mitigating actions such as delaying, cancelling and rerouting particular affected flights. These actions aim at maintaining both the network’s resilience and safety at the acceptable level under given conditions.Large scale disruptive events, which can compromise the resilience and friability of a given air transport network, include bad weather, failures of particular (crucial) network components, the industrial actions of the air transport staff, natural disasters, terrorist threats/attacks and traffic incidents/accidents.The methodology is applied to the selected real-life case under given conditions. In addition, this methodology could be used for pre-selecting the location of airline hub airport(s), assessing the resilience of planned airline schedules and the prospective consequences, and designing mitigating measures before, during, and in the aftermath of a disruptive event. As such, it could, with slight modifications, be applied to transport networks operated by other transport modes.     

基于流固耦合方法的离心式压气机叶片强度与振动特性研究

采用流体动力学及有限元方法,对某型带分流叶片的离心式压气机叶轮进行了单向流固耦合分析。建立了叶轮单个通道的三维流场模型,得到某转速下压气机叶轮内部流场的应力分布,然后将气动力施加在叶片上,获得离心力和气动力共同作用时主叶片及分流叶片上的应力分布及最大变形量,最后对比分析了离心力与气动力对叶片应力应变和振动特性的影响。     

美国气垫登陆艇的技术发展及分析

基于美国气垫登陆艇(LCAC)的研制实情及其最近的延寿计划(SLEP)和其未来替代者——舰岸连接器(SSC)的发展趋势,对LCAC的快速性等总体性能进行计算和分析,并追踪LCAC有关新技术在芬兰T-2000艇与韩国LSF-II艇上的应用情况。