摘要
某柴油机新设计的排气歧管在试验过程中出现开裂现象,通过全面分析该排气歧管的热应力和振动特性,应用AVL公司的FIRE软件,建立排气歧管的有限元模型并确定它的边界条件,对CFD分析计算出排气歧管内外表面的温度和热传递系数,然后用非线性结构分析软件ABAQUS软件计算排气歧管的温度场和热应力;同时也对排气歧管的振动特性进行了计算。结果表明排气管开裂不是由热应力引起的,而是共振的原因,建议更改排气歧管加强筋以提高它的刚度,提高排气系统的固有频率,避免与发动机产生共振。
A newly-designed exhaust manifold for a diesel engine had cracks in the course of the experiment. By analyzing the thermal stress and vibration characteristic of the exhaust manifold entirely and using AVL software FIRE to set the limited models of exhaust manifold and ascertain the edge conditions, the temperatures and heat transfer coefficients （HTC） on interior and exterior walls of exhaust manifold were calculated by computational fluid dynamics （CFD） analysis. Then, the fields of temperature and thermal stress were calculated by using non-structural software ABAQUS. At the mean time the exhaust manifold vibration characteristic was also calculated. The results showed that the cracks of the exhaust manifold were caused by resonance instead of the thermal stress. It was suggested that the reinforcing steel should be replaced by a stronger one to enhance its rigidity and to raise the innate frequency of the exhaust system to avoid the resonance in the engine.
出处
《实验力学》
CSCD
北大核心
2007年第5期500-504,共5页
Journal of Experimental Mechanics
基金
YC4112ZLQ型柴油机的研究开发项目(0411017)
中国机械工业科学技术二等奖
关键词
柴油机
排气歧管
开裂
CFD
diesel engine
exhaust manifold
crack
computational fluid dynamics （CFD）
作者简介
通讯作者：刘志勇（1969-），男，硕士研究生，副教授。主要研究方向为动力工程的振动及噪声控制技术。E-mail：myfnan@yahoo．com．cn
