Computational Assessment of Thermal Conductivity of Compacted Graphite Cast Iron

Yue Wu,Dong Tao,Zhong Yang,Tong Yang,Jianping Li,Yongchun Guo,Minxian Liang,Zhijun Ma

doi:10.1155/2019/8562102

Yue Wu, Dong Tao + Show 6 more

Open Access

https://doi.org/10.1155/2019/8562102

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Abstract

Two-dimensional FE models of CGI with different pearlite contents for thermal conductivity analysis were established according to the real metallographic images obtained by Pro/E and ANSYS. Meanwhile, thermal conductivity of CGI with different pearlite contents was tested through the laser flash method. It is indicated that the thermal conductivity of CGI declines with the increase of pearlite. When pearlite is increased from 10% to 80%, the experimental values decline from 46.63 W/m·K to 36.86 W/m·K, reducing by 21%. However, this declining tendency becomes gentle and slight when pearlite is more than 40%. In addition, the calculation results with the consideration of interfacial contact thermal conductance (ICTC) and pearlite are much close to experimental values; especially when pearlite is 80%, the difference between them is only about 2%. It can be concluded that the FE models are convenient and reasonable to analyze thermal conductivity of CGI.

Highlights

As a preferred material for engine components at high temperature, such as cylinder head, compacted graphite cast iron (CGI) exhibits a super combination of excellent mechanical properties and outstanding thermal conductivity [1, 2]
When graphite grows along the basal planes preferentially, it becomes lamellar and constitutes eutectic cells, which build 3D structure and make heat to spread through graphite eutectic cells quickly
Due to excellent thermal conductivity, heat flux of graphite is higher than that of matrix, which indicates that the heat transmission would pass through the graphite preferentially

Summary

Introduction

As a preferred material for engine components at high temperature, such as cylinder head, compacted graphite cast iron (CGI) exhibits a super combination of excellent mechanical properties and outstanding thermal conductivity [1, 2]. Ere are many models to calculate thermal conductivity, such as Helsing model [13, 14], Maxwell model, Bruggeman model, and Hasin– Shtrikman model [15], which are convenient to calculate and apply These models only suit cast iron with ferric matrix. Finite element (FE) simulation has been used for analyzing the thermal conductivity of cast iron [16, 17]. There are two purposes: (1) attempting to build a twodimensional heat conduction model of CGI by using FE methods and (2) analyzing the influence of pearlite and ICTC on the thermal conductivity of CGI

Building of FE Models

Results and Discussion

Conclusions