The Research On CFD And NHT Methods Of A High-speed Gasoline Engine Cylinder Head And Water-jacket

Cylinder head is an important component of internal combustion engine andits strength research and reliability is therefore a critical problem. Under anormal operating cycle of an engine, there are man y loadings which affects oncylinder head such as bolt pre-tightening force, explosion pressure ofcombustion gas, thermal stress and assembly stress of assemblies. However, thepressure of explosion of gas belongs to cyclic loading that may lead to a fatiguefailure. It will have a great effect on cylinder head’s reliability to run acomprehensive analysis of thermal load and strength.This paper took a naturally aspirated inline four-cylinder gasoline engine asstudy object and utilized theories of CFD, NHT and fatigue strength and methodsof FSI to simulate the flow and heat transfer phenomenon of cooling water. Onthis basis the author put forward nine improvement projects in which the locationand bore diameter were different from each other. Had been compared withcalculation results of temperature and velocity fields of each project, two desiredplans were chosen. Then the author simulated the thermal stress, factor and lifeof fatigue strength of cylinder head and ensured the only improvement plan is thebest.Throughout the analysis, the author summarized an important principal ofcylinder head in this type that the two series of water holes near flame faceaffects signall y on cooling performance. Besides, multi-physics fields anal ysisplayed an important role in structural design and improvement. It proved thatmulti-physics anal ysis lead to a reasonable result and it is not objective toevaluate a improvement project base on a single ph ysical trend.