石墨连通性对蠕墨铸铁导热性能影响的数值模拟

Numerical Simulated Effect of Graphite Connectivity on Thermal Conductivity of Vermicular Graphite Cast Iron

作为高功率密度柴油发动机缸盖的首选材料,蠕墨铸铁的导热性能对零部件服役寿命的影响越来越大。文中采用有限元方法,根据X射线断层扫描技术(XRT)得到石墨三维形貌分别建立实体和抽象模型,从不同角度考察石墨三维连通性特征对蠕墨铸铁导热性能的影响。研究结果表明:石墨三维连通性对蠕墨铸铁导热性能的贡献不足2%,单纯提高蠕铁中石墨的三维连通性,不能有效提高蠕铁的导热性能。

The thermal conductivity of vermicular graphite cast iron (VGI),the preferred material for the cylinder head of high power density diesel engines,has greater influence on the service life of the parts.In this paper,the finite element (FE) method is applied to establish physical and abstract models according to the 3D morphology of graphite obtained by means of X ray Tomogrphy (XRT).The effect of the 3D connectivity characteristics of graphite on the thermal conductivity of VGI is investigated from different angles.The results show that the contribution of graphite 3D connectivity to the thermal conductivity of VGI is less than 2%;therefore,the thermal conductivity of VGI can not be improved effectively only by increasing the connectivity of graphite phase.