针对某直列四缸增压柴油机排气歧管在台架耐久试验中出现开裂现象,应用有限元(finite element analysis,FEA)-计算流体力学(computational fluid dynamics,CFD)耦合方法对排气歧管进行了热应力分析。排气歧管热应力分析模型中的材料性...针对某直列四缸增压柴油机排气歧管在台架耐久试验中出现开裂现象,应用有限元(finite element analysis,FEA)-计算流体力学(computational fluid dynamics,CFD)耦合方法对排气歧管进行了热应力分析。排气歧管热应力分析模型中的材料性质随着温度变化的关系由试验测定;在相应发动机工况下对模型预测的温度场和台架上测量的排气歧管温度进行对比,以对模型进行标定。应用标定后的模型分析排气歧管在给定热负荷条件下的应力-应变分布。FEACFD耦合分析结果表明:发生开裂的区域为高塑性应变区,从而推论导致排气歧管开裂原因为热力耦合应力作用下产生的塑性变形,即失效形式为热机械疲劳。以等效塑性应变作为塑性变形的度量及许可的等效塑性应变经验值为判据对排气歧管进行了设计改进,并从三种改进方案中找出最安全的方案进行试验验证,改进后的排气歧管顺利通过发动机台架耐久试验考核。展开更多
This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components h...This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components have complex geometries and to obtain the thermal contractions, in the research, used the method of finite element analysis. The phenomena of thermal contractions are studied for the cold-start situations at extreme low temperature, knowing that the cold-start phase of an internal combustion engine is the main factor that determines moving rotational and translational parts wear life. Checking the proper choice of clearance is particularly important, as the use of inappropriate values of it leads to rapid operation destruction of the engine group components. The results obtained for the thermal clearances of crankshaft bearings are mathematically modeled and the relations can be used for calculating the clearances. The mathematical models are also useful for implementing in different software tools.展开更多
文摘针对某直列四缸增压柴油机排气歧管在台架耐久试验中出现开裂现象,应用有限元(finite element analysis,FEA)-计算流体力学(computational fluid dynamics,CFD)耦合方法对排气歧管进行了热应力分析。排气歧管热应力分析模型中的材料性质随着温度变化的关系由试验测定;在相应发动机工况下对模型预测的温度场和台架上测量的排气歧管温度进行对比,以对模型进行标定。应用标定后的模型分析排气歧管在给定热负荷条件下的应力-应变分布。FEACFD耦合分析结果表明:发生开裂的区域为高塑性应变区,从而推论导致排气歧管开裂原因为热力耦合应力作用下产生的塑性变形,即失效形式为热机械疲劳。以等效塑性应变作为塑性变形的度量及许可的等效塑性应变经验值为判据对排气歧管进行了设计改进,并从三种改进方案中找出最安全的方案进行试验验证,改进后的排气歧管顺利通过发动机台架耐久试验考核。
基金funds project PRO-DD (POS-CCE, O.2.2.1., ID 123, SMIS 2637, ctr. No 11/2009) for providing the infrastructure used in this work
文摘This paper presents how the contractions of the main components of a V6 motor with low engine displacement are determined for the cold-start phase under extreme low temperature. Internal combustion engine components have complex geometries and to obtain the thermal contractions, in the research, used the method of finite element analysis. The phenomena of thermal contractions are studied for the cold-start situations at extreme low temperature, knowing that the cold-start phase of an internal combustion engine is the main factor that determines moving rotational and translational parts wear life. Checking the proper choice of clearance is particularly important, as the use of inappropriate values of it leads to rapid operation destruction of the engine group components. The results obtained for the thermal clearances of crankshaft bearings are mathematically modeled and the relations can be used for calculating the clearances. The mathematical models are also useful for implementing in different software tools.
