发动机排气歧管流固耦合仿真

应用AVL-fire软件和Abaqus软件对某发动机排气歧管进行流固耦合仿真.对排气歧管材料进行各温度下的材料试验,得到准确的材料在不同温度下的属性曲线.由AVL-fire软件和Abaqus软件进行流固耦合仿真得到排气歧管的温度场分布,并进行排气歧管应力和应变分析.仿真结果与试验结果的对比表明,塑性应变高的区域正是发生开裂的区域.     

排气歧管热机耦合强度和密封压力模拟分析

应用Abaqus对某发动机排气系统进行温度场计算,并在冷热循环工况下计算排气歧管的热应力、塑性变形以及密封压力.结果可以为排气歧管结构设计提供参考.     

发动机排气歧管热应力分析

应用Fire软件建立排气歧管CFD计算分析模型,模拟计算发动机在不同工况下的温度和换热系数(Heat Transfer Coefficient,HTC).用Abaqus建立热机疲劳分析模型,利用CFD结果中的温度和换热系数作为热机械疲劳分析的边界条件,计算各工况点下排气歧管的温度场和塑性变形等结果,并对结果进行评估,提出相应的改善意见,为后续发动机零部件结构强度开发提供参考,从而大大减少试验开发的工作量和费用,加快开发进度.     

基于Abaqus的汽油发动机排气门温度场模拟分析和试验

对某4缸汽油发动机排气门进行建模和计算.采用2种建模方法分析气门的温度场分布,并与试验测温结果进行对比.结果表明:建模时考虑缸盖、阀座、导管与气门的接触导热能非常准确地模拟气门温度分布;传统的采用第三类边界条件的换热计算方式模拟分析得到的结果与试验测温结果误差较大.根据标定好的仿真模型,更改导管材料,可达到气门温度降低19.3℃的效果.     

基于Pro/ENGINEER的某型排气歧管强度与模态分析

排气歧管是汽车发动机排气系统的重要部件,它的结构设计与发动机排气系统性能密切相关。文中采用有限元分析的方法对某品牌汽车发动机排气歧管关键部分进行排气压力下和温度载荷下的强度分析,对模型整体进行模态分析。对本产品的结构稳定性予以分析说明,为结构设计提供依据。     

缩比试验模型设计与验证

为了预示导弹地下发射井中的噪声环境、检验某型多孔吸声材料的实际吸声效果,通过缩比模型试验进行了验证和仿真.按照缩比原则设计了缩小比例为1∶10的模型发动机,采用网格计算方法对缩比模型和原型发动机之间的温度场、速度场和压力场进行了定常仿真分析与比较.结果表明,缩比试验的结果与井下原型导弹的射流流场具有可比性,试验测量数据可以作为评价吸声材料的实际应用效果.对缩比模型的设计过程进行了研究.通过对模型发动机流场和原型发动机流场的仿真和比较,验证了缩比试验技术方案的合理性.     

基于内燃机排气性能分析研究

排气歧管是内燃机排气的主要组成部分,排气歧管的气体流动性能和动压性能直接影响到内燃机的动力性、排放性和经济性,如排气歧管的结构不合理,内燃机就会降低功率,在行驶中,由排气因懂得振动会导致其断裂,致使车辆出现漏气现象。因此排气歧管的结构型式的优化设计具有重大意义。     

燃烧机构内部流场的数值仿真和方案优选

为优化燃烧机构的结构设计,用FLUENT建立某燃烧机构内部流场数值仿真模型;针对进口流量和出口直径参数各取3个不同的值,组合成9种方案仿真内部温度场和压力场分布;通过比较不同方案的内部温度场及压力场仿真结果,优选出合适的方案. 仿真结果与试验结果较为吻合,说明采用数值仿真方法可为燃烧机构方案设计提供参考.     

基于Abaqus的汽车发动机罩应力响应分析

利用Abaqus建立某汽车发动机罩的详细模型,对发动机罩的关闭过程进行显式动力学仿真,研究发动机罩大力关闭时的应力响应.通过试验测试发动机罩局部的应变,并与计算结果对比分析.结果表明该方法可准确预测发动机罩关闭时的瞬态应力响应,指导发动机罩的强度耐久设计.     

基于HyperMesh的排气消声器开裂分析及优化设计

一、消声器的安装结构及作用 排气系统的主要作用是将发动机工作时产生的废气排出,并且降低排气时所产生的噪声,减少环境污染和产生辅助制动.排气系统主要是由发动机排气歧管、排气管、消声器、排气管路悬置和排气辅助制动阀组成.     

客车发动机舱热管理系统的数值仿真与实验验证

依据整车环境模拟实验,选取最大扭矩点、中间点和最大功率点（对应的发动机转速分别为1 800,2 800和3 450 r/min）作为发动机舱热管理系统分析的3个工况,应用FLUENT建立发动机舱热管理系统的三维仿真模型,根据实验边界条件,进行风速场和温度场的耦合仿真。采用稳态计算方法,获得发动机舱内外稳定的风速场和温度场分布。对比分析发现仿真结果与实验结果的均方根相对误差在合理范围内,从而验证该发动机舱热管理系统仿真模型的有效性。     

Shape optimal design of an engine exhaust manifold

An engine exhaust manifold made of cast iron cracks during thermal shock testing. The test process is simulated by finite element analysis. The manifold is formulated as a linear heat transfer and thermoelasticity problem in a variational form. Analytical expressions for shape design sensitivities of general three-dimensional problems are presented, using the material derivative approach. A hybrid approach is described and used during the optimization process. This approach takes advantage of the direct and the adjoint variable methods and is the most efficient in calculating the sensitivity of the structural responses. After the finite element model is verified by comparing the results with those from testing, the engine exhaust manifold is optimized with respect to its geometry.     

基于Abaqus的某柴油机排气歧管热固耦合分析

排气歧管在工作状态下会承受很高的环境温度,而在较高的环境温度下金属材料的力学性能和热学性能通常会发生较大变化.通过添加实测的各种部件材料随温度变化的性能参数,介绍某柴油机排气歧管热固耦合分析过程,展现使用AVL系列软件与Abaqus软件进行的排气歧管热固耦合分析流程.     

发动机排气管流-固-热强耦合分析

为研究发动机排气管在流-固-热强耦合作用下的复杂工况,用INTESIM软件中流-固-热强耦合的方法计算某型发动机排气管在工作过程中流场、温度场、热变形和热应力的分布情况.结果表明,与传统的分析方法相比,INTESIM的强耦合方法收敛性更好,并且可以在同一软件平台下对模型耦合矩阵方程直接求解得到结构应力场、位移场、流场和温度场的所有结果.     

基于Abaqus的催化器总成热循环应力分析

基于Abaqus的稳态热分析和热力耦合分析功能,在给定热边界条件下计算某催化器总成稳态热分布;利用Abaqus的顺序耦合功能计算催化器总成在循环温度下的热应力,得到关键部件处的热应力和塑性应变.根据结果初步评价该催化器总成在热循环冲击载荷下的强度特性,为热冲击试验和结构优化提供参考.     

Nonlinear Observer-based Control Design and Experimental Validation for Gasoline Engines with Exhaust Gas Recirculation

This paper presents a nonlinear observer-based control design approach for gasoline engines equipped with exhaust gas recirculation (EGR) system. A mean value engine model is designed for control which includes both the intake manifold and exhaust manifold dynamic focused on gas mass flows. Then, the nonlinear feedback controller based on the developed model is designed for the state tracking control, and the stability of the close loop system is guaranteed by a constructed Lyapunov function. Since the exhaust manifold pressure is usually unmeasurable in the production engines, a nonlinear observer-based feedback controller is proposed by using standard sensors equipped on the engine, and the asymptotic stability of the both observer dynamic system and control dynamic system are guaranteed with Lyapunov design assisted by the detail analysis of the model. The experimental validations show that the observer-based nonlinear feedback controller is able to regulate the intake pressure and exhaust pressure state to the desired values during both the steady-state and transient conditions quickly by only using the standard sensors.     

Real-time control oriented HCCI engine cycle-to-cycle dynamic modelling

For homogeneous charge compression ignition (HCCI) combustion, the auto-ignition process is very sensitive to in-cylinder conditions, including in-cylinder temperature, in-cylinder components and concentrations. Therefore, accurate control is required for reliable and efficient HCCI combustion. This paper outlines a simplified gasoline-fueled HCCI engine model implemented in Simulink environment. The model is able to run in real-time and with fixed simulation steps with the aim of cycle-to-cycle control and hardware-in-the-loop simulation. With the aim of controlling the desired amount of the trapped exhaust gas recirculation (EGR) from the previous cycle, the phase of the intake and exhaust valves and the respective profiles are designed to vary in this model. The model is able to anticipate the auto-ignition timing and the in-cylinder pressure and temperature. The validation has been conducted using a comparison of the experimental results on Ricardo Hydro engine published in a research by Tianjin University and a JAGUAR V6 HCCI test engine at the University of Birmingham. The comparison shows the typical HCCI combustion and a fair agreement between the simulation and experimental results.