一个应用复合箱体结构传动箱的柴油发电机组设计

因运载车辆或其它条件限制,在某些情况下,柴油发电机组设计中需将发电机布置在柴油发动机的侧面,以减小机组在长度方向的尺寸。本文对该种布置方式的力学特性进行了分析,并从传动齿轮箱设计和柴油发电机组结构总成方面提出了合理的设计方案,产品经运行效果良好,证明具有使用价值。     

铈锆氧化物固溶体制备方法的比较研究

分别采用均匀沉淀法和共沉淀法制备了铈锆氧化物固溶体,研究了制备方法对铈锆氧化物固溶体的晶体结构、比表面积以及储氧能力的影响。结果表明,均匀沉淀法制备的铈锆氧化物固溶体的比表面积小,储氧能力较强,所制得的三效催化剂具有良好的催化活性,但该方法所制备的铈锆氧化物固溶体耐高温性能较差。     

汽车上的电磁干扰及抑制措施

电磁干扰以多种方式存在于汽车内部，这些干扰对车载电子装置及无线电接收设备会产生不同程度的影响。就车内电气部件所产生的电磁干扰及其形成机理提炼出来进行分析，并提出了有效的抑制措施。     

汽车制动液的发展与选用

汽车制动液是保证车辆有效制动和行驶安全的专用化学制品。介绍了制动液的基本要求、发展概况、以及制动的性能和选用中应注意的事项。     

车辆-轨道耦合动力学理论在现代机车车辆设计中的应用实践

介绍了车辆 轨道耦合动力学理论在新型机车车辆研制中的最新应用情况,包括在200km/h"天梭号"高速机车设计、170km/hSS7E型提速客运电力机车改进设计,以及120km/h提速货运电力机车研制中的应用实践。文章着重从提高高速机车蛇行运动稳定性、改进SS7E型客运机车横向动力性能以及降低提速货运机车轮轨动力作用等方面进行了详细论述。结果表明,车辆 轨道耦合动力学理论在现代铁路机车车辆研制中取得了显著成效,具有广阔的应用前景。     

Evaluation of added resistance in regular incident waves by computational fluid dynamics motion simulation using an overlapping grid system

A computational fluid dynamics simulation method called WISDAM-X was developed to evaluate the added resistance of ships in waves. The Reynolds-averaged Navier–Stokes (RANS) equation was solved by the finite-volume method and a MAC-type solution algorithm. An overlapping grid system was employed to implement rigorous wave generation, the interactions of ships with incident waves, and the resultant ship motions. The motion of the ship is simultaneously solved by combining the solution of the motion of the ship with the solution of the flow about the ship. The free surface is captured by treatment by the density-function method. The accuracy of WISDAM-X is examined by a comparison with experimental data from a container carrier hull form, and shows a fairly good agreement with respect to ship motion and added resistance. Simulations were also conducted for a bow-form series of a medium-speed tanker to examine the effectiveness of the WISDAM-X method as a design tool for a hull form with a smaller resistance in waves. It was confirmed that the WISDAM-X method can evaluate the added resistance with sufficient relative accuracy and can be used as a design tool for ships.     

The clinical analysis of three methods in the treatment of intracranial bacterial infection

Objective To analyze the effect of three therapeutic methods to find an optimal approach to the treatment of intracranial bacterial infection by retrospectively reviewing 33 intracranial bacterial infection patients who were admitted from 1995 to 2008 in oar hospital. Methods The treatments by intermittent lumbar puncture,continuous lumbar subarachnoid space drainage, and embedment of Ommaya cyst for continuous drainage from the ventricles were performed in 15 cases, 12 cases, and 6 cases respectively along with intravenous application of full dose of antibiotics. Results Nineteen cases were cured and the best prognosis was from the group of Ommaya cyst embedment and continuous drainage from the ventricles. Conclusion Management goals are prompt recognition of the central nervous system (CNS) infection, rapid identification of causative organisms and initiation of treatment with the optimal management methods for complications. Embedment of Ommaya cyst for continuous drainage from the ventricle is a safe and effective treatment for intracranial bacterial infection.     

On the application of hydraulic theory to the deep-water flow through the Irbe Strait

A flow-dependent critical-point method for investigating topographically controlled flow in natural channels is applied to the bottom current through the Irbe Strait connecting the Baltic proper and the Gulf of Riga. This approach is based on the functional formalism due to Gill [Gill, A.E., 1977. The hydraulics of rotating-channel flow. J. Fluid Mech., 80, 641–671.], and here is used for the stratified flow structure observed during the IRBEX-95 field campaign. A critical section of the realizable flow regime was found to be located slightly downstream of the most pronounced horizontal constriction of the channel. The predicted baroclinic volume flux 7200 m³ s⁻¹ overestimates the observed mean bottom-water transport by around 30%, a discrepancy which most likely can be explained by the lack of sea level conditions and friction in the model.     

基于OpenFOAM的发动机舱回流计算方法研究

研究车辆在怠速工况下的发动机舱热空气回流问题，基于OpenFOAM 软件进行回流计算方法的开发。通过设置监控面及组分转换面来重新定义格栅新空气和舱内回流热空气等组分，可直接计算出回流在监控面上的分布及回流率和回流量。根据开发的方法对某款插电式混合动力汽车（Plug-in Hybrid Electric Vehicle，PHEV）车型进行计算并提出不同的优化方案，使其发动机舱回流率从32.7% 分别降低至24.0%和9.3%，回流量从0.169 kg/s分别降低至0.128 kg/s和0.048 kg/s，从而降低了冷凝器等散热器的进风温度，提高了怠速工况下热管理系统的性能。     

Flow-field guided steering control for rigid autonomous ground vehicles in low-speed manoeuvring

ABSTRACT

This paper studies the low-speed manoeuvring problem for autono-mous ground vehicles operating in complex static environments. Making use of the intrinsic property of a fluid to naturally find its way to an outflow destination, a novel guidance method is proposed. In this approach, a reference flow field is calculated numerically through Computational Fluid Dynamics, based on which both the reference path topology and the steering reference to achieve the path are derived in a single process. Steering control considers three constraints: obstacle and boundary avoidance, rigidity of the vehicle, plus the non-holonomic velocity constraints due to the steering system. The influences of the parameters used during the flow field simulation and the control algorithm are discussed through numerical cases. A divergency field is defined to evaluate the quality of the flow field in guiding the vehicle. This is used to identify any problematic branching features of the flow, and control is adapted in the neighbourhood of such branching features to resolve possible ambiguities in the control reference. Results demonstrate the effectiveness of the method in finding smooth and feasible motion paths, even in complex environments.