基于CFD的卡车机舱热环境分析与控制

针对某长头卡车驾驶室底钣金地板过热问题,基于传热学理论,建立汽车机舱模型并设定边界条件。运用CFD分析软件对发动机舱的流场和温度场进行数值仿真,分析发动机舱内的流体流动和散热情况,得到驾驶室底钣金地板过热的主要影响因素,提出相应的解决方案,通过仿真和试验进行验证。结果证明,对热源采取隔热措施,可有效抑制辐射和降低驾驶室底钣金地板温度。     

汽车发动机舱软管干涉试验用六自由度可调式夹具设计及仿真

在汽车设计阶段,获得汽车发动机舱的空间利用情况以及软管、线束之间的干涉情况对发动机舱设计有着指导意义。针对汽车发动机舱软管干涉试验缺乏多自由度可调式试验夹具的问题,设计了一套能适用于多类型发动机且能实现六自由度调整以满足模拟发动机舱振动的可调式夹具。利用ANSYSWorkbench有限元分析软件对发动机总成辅助定位臂、挡板定位臂进行了强度、刚度分析。仿真验证表明,该套夹具结构设计合理,能够满足汽车发动机舱软管干涉试验的试验要求,对其他汽车发动机舱试验硬件平台设计具有一定的借鉴意义。     

某商用车发动机舱散热性能提升与试验研究

为降低某商用车发动机舱温度以及发动机出水口冷却液温度,运用数值计算与整车试验相结合方法,对汽车发动机舱进行散热特性研究并对机舱提出相应改进方案。改进结果显示:发动机舱空间点温度明显下降,发动机出水口冷却液温度下降,满足汽车散热要求。通过计算结果与试验数据的对比分析,验证了数值计算的准确性,为发动机舱的布置提供了理论依据,缩短了研发周期。     

CFD技术在机舱散热性能研究及优化中的应用

为解决发动机舱过热问题,对某前置客车发动机舱的流动特性进行数值模拟计算。并通过换热器风阻特性实验及客车内外流场试验,验证仿真模型的正确性。通过分析发动机舱重要截面的温度场和速度场,找出机舱内的温度异常点及流场分布不合理的地方,分析产生热回流及进风量较小原因,提出改进方案。通过前移冷却模块和在格栅处增加导流板可有效减少热回流、增大进气量。仿真结果验证改进方案可有效降低发动机舱整体温度。仿真模拟在车辆前期开发过程中起着重要作用可以缩短开发周期,节省开发成本。     

基于CFD的汽车发动机舱热管理及优化策略

为全面准确研究揭示与汽车发动机舱相关的热管理问题,设计形成并且具体运用与汽车整体开发工作流程相契合的发动机舱管理工作模拟分析技术流程,旨在为相关领域的研究人员,以及一线技术工作人员,创造并且提供扎实且有效的经验参考支持条件。     

T815汽车发动机过热原因分析与排除

通过分析T815汽车发动机过热的主要原因．提出排除T815汽车在使用维修过程中出现过热现象的有效措施,避免T815汽车因过热引起的汽车动力性能下降、拉缸、烧瓦、抱轴等机械事故的发生。     

发动机舱内温度场的可视化分析及改善措施

在紧凑型轿车上，发动机的进气歧管受到来自于多种热源的加热，周围的温度较高，影响了汽车的燃油经济性和动力性。用可视化方法研究了发动机舱内温度在不同工况下的变化规律，使温度变化规律更加直观，有助于找出问题的关键所在和改进方案的制定。由此而提出的在发动机罩盖上开孔的改进方案，使发动机舱内温度得到明显降低。实验表明发动机充气效率和扭矩均得到显著提高，燃烧效率得到了改善，从而提高了汽车动力性和经济性。     

LPG公交客车发动机舱散热特性的CFD分析

针对液化石油气公交客车在高温环境下低速行驶时发动机舱温度过高的问题,利用计算流体动力学和传热学,研究公交客车发动机舱内空气对流传热基本规律.为了定量分析在恶劣工况下的发动机舱内空气流动速度场和温度场特性,在UG中建立了发动机舱的几何模型,并利用FLUENT软件对发动机舱的散热特性进行了数值仿真,通过仿真与分析,获取了在选定工况下的发动机舱内空气气流速度场和温度场,可知发动机舱内的不合理布局是引起发动机舱温过高的主要因素之一,同时对发动机舱的合理布局提出了建议.     

航空发动机舱温超限故障分析

对某飞机的发动机舱温超限的故障进行分析,针对发动机舱温超限现象对发动机舱通风冷却系统的进气方式提出了多种方案。通过理论和试验的对比分析,获得了合理的进气方案,解决了发动机舱后段温度超限故障,为发动机舱通风冷却系统设计提供依据。     

风扇结构对发动机冷却系统的影响研究

为研究风扇结构对冷却系统进风效率的影响,运用多参考坐标系法,建立了两种不同结构风扇模型以及某重型载货汽车发动机舱模型,对其三维流场进行数值模拟。在对风扇流场及发动机舱内流场进行分析的基础上,研究了冷却系统风扇结构对进风效率的影响。分析表明:相对于无扇框风扇,扇叶扇框一体式风扇有效地减少了叶片端的回流,增加了散热器的进气量,冷却系统进风量平均提高了3.47%,减小了冷却常数,增强了冷却系统的冷却能力,达到了节能的目的。     

轮机模拟器中传感器信号模拟器的设计

轮机模拟器系统是现代航海教育的必备设施,它通过硬件和仿真软件相结合的方式模拟船舶机舱自动化的运行过程,该系统中大多数传感器信号都是通过信号模拟器模拟的.以5600国际标准箱(TEU)集装箱轮自动化机舱为模型,结合当前嵌入式技术特点开发了一款新型信号模拟器,可精确地模拟出多种常用传感器标准信号源,操作方便、工作可靠.     

SUV车型机舱冷却性能仿真分析与优化

针对某SUV车型中低速爬坡工况时发动机水温偏高问题,应用一维与三维联合仿真方法对车辆进行数值仿真分析,并对仿真的精准性进行试验验证.通过建立三维整车模型,对机舱进行冷流场计算,结合一维仿真发现发动机出水温度偏高,未能满足设计要求.对机舱内流场进行分析,发现冷却模块前端进气通道存在明显涡流、流动死区的现象.提出调整格栅开...     

Experimental Investigation of Air Bearings for Gas Turbine Engines

An experimental gas-bearing test program was initiated to establish the answer to two specific questions. Is present-day gas bearing technology accurate enough to predict actual bearing performance under typical jet engine operating conditions? And, are gas journal and thrust bearings capable of carrying the required high operating loads that can be imposed by the engine when maneuvering at high. altitudes, which are considered the most severe bearing operating conditions? A bearing element component rest rig was built to simulate jet engine conditions. Tests were performed and the results, reported herein, indicate positive answers lo the above questions.     

Unlubricated gross slip fretting wear of metallic plasma-sprayed coatings for Ti6Al4V surfaces

Plasma-sprayed Al–bronze or CuNiIn coatings are often applied to protect against fretting wear and extend the operational life of Ti-alloy compressor blades in turbine engines. In order to develop a fundamental understanding of how these coating systems perform under gross slip fretting conditions, bench level fretting wear tests were conducted at room temperature to simulate cold engine startup. Alternative coatings such as plasma-sprayed molybdenum and nickel were also evaluated because of their potential for reducing fretting wear under certain simulated engine conditions. The combination of scanning electron microscopy (SEM), surface profilometry, surface chemistry (EDS), and friction analysis were used to study coating performance and evaluate the interfacial wear mechanisms. In this study, it was determined that all coatings caused significant damage to the mating Ti6Al4V surfaces and that the wear mechanisms were all similar to those of the uncoated baseline case.     

内燃机振动、噪声的多体动力学分析

以某六缸柴油机为研究对象，运用多体动力学对内燃机振动、噪声进行仿真分析。建立了高质量的有限元模型和仿真模型，用非线性阻尼弹簧模拟运动件间的连接。通过发动机的表面振动速度来评价辐射噪声，改进发动机的结构，增加局部刚度。对发动机两种结构的计算结果进行了比较，取得了降低振动噪声的结果。     

基于高能量转换效率的旋转式气动发动机动力学分析

针对目前常用气动发动机能量转换效率低的现状,提出一种新型旋转凸轮活塞式气动发动机结构。根据气动发动机工作原理,针对旋转式气动发动机膨胀容积大,缸内高压气体压力直接推动凸轮活塞旋转对外做功的结构特点,分析缸内气体压力与输出扭矩之间的关系,建立动力学模型,并以此动力学模型为基础,利用Matlab/Simulink软件对该发动机单缸工作过程进行计算机仿真分析。仿真结果表明:旋转式气动发动机具有低速时有效扭矩大,能量转换效率高的优点。     

车用柴油机燃烧和热流分析的数值研究

利用商用软件STAR—CD及ES—ICE对某D6114柴油机在的缸内燃烧过程进行了数值模拟计算,分析和比较了不同喷油提前角对缸内燃烧过程和燃烧室表面热流的影响。研究结果表明：喷油提前角提前,柴油机缸内的燃烧效果优于喷油提前角推迟,燃烧过程中缸内的压力和温度比推迟喷油提前角时要大,同时缸内的最高燃烧压力和最高温度也高;喷油提前角对缸盖和活塞顶壁面平均热流的影响与其对缸内平均温度的影响相似,对缸套壁面的影响是喷油提前角提前越早,传给缸套的热流越小。数值计算结果为高功率、高强化和低热损的柴油机设计提供理论依据。．     

高温线接触条件下表面抗磨损性能的试验研究

模拟内燃机汽缸－活塞环工况,采用ＳＲＶ摩擦磨损试验机进行高温线接触条件下,抗磨损性能的试验。试验表明：经激光微精处理的试件,在参数合理的情况下可使其抗磨损性能大幅度提高。这为发动机汽缸处理的实际应用提供了参考。     

The experimental study of atomization characteristics of gasoline spray impinging on glow plug

In order to reduce the exhaust emissions of a spark ignition engine, it is important not only to improve the catalyst conversion efficiency, but also to directly reduce the engine-out exhaust emissions during a cold starting of the engine and warm up periods. The purpose of this study is to evaluate feasibility of a glow plug for an early fuel evaporator. In order to promote atomization, gasoline is injected on the glow plug with room temperature (20°C) and high temperature (250°C). To analyze the spray behavior characteristics, a PMAS is used to measure the SMD and the dropsize distribution of an impinging spray and a free spray. Results show that the evaporation rate of the impinging spray on the high temperature surface of the glow plug was higher than that of the free spray on the room temperature surface.     

Numerical analysis and design optimization of engine room to improve cooling performance for a mid-class excavator

Excavators perform high-load operations in mainly a fixed place, and the heat balance is determined by the performance of the cooling system. Prediction of the cooling system performance is difficult due to non-uniformity of the air flow field inside the engine room and complicated boundary conditions. In the present study, CFD analysis of the engine room was performed for a preliminary evaluation of the cooling system performance of an excavator, and the analysis technique was validated by comparison with heat balance test results for an actual vehicle. CFD analysis was performed according to the design of experiment method for three types of internal design variables and two types of external design variables. A sensitivity analysis of the engine room design variables was performed and a regression model for the major design variables was proposed. Based on the regression model, optimization was conducted for the engine room layout for performance improvement.