An Analytical Modeling for Effective Thermal Conductivity of Multi-Phase Transversely Isotropic Fiberous Composites Using Generalized Self-Consistent Method

2012 ◽  
Vol 249-250 ◽  
pp. 904-909 ◽  
Author(s):  
Syed Aadil Hassan ◽  
Hassaan Ahmed ◽  
Asif Israr

In this paper a theoretical relationship for the effective thermal conductivity of a multiphase transversely isotropic composite system is obtained. The Generalized Self-Consistent Method and simple energy balance principle is employed to derive a more appropriate model. In the derivation, it is assumed that the orientation of fiber within the transversely isotropic composite system is unidirectional and surrounded by two different phases of porous and matrix phase. A combined effect of these three different phases on the effective thermal conductivity of the composite system in transverse direction is studied. The effect of the interfacial contact conductance between the fibers and porous medium is also considered. Results of effective thermal conductivity are plotted against volume fraction and conductance which shows extremely good agreement.

2010 ◽  
Vol 152-153 ◽  
pp. 269-273
Author(s):  
Mei Zhang ◽  
Peng Cheng Zhai

A new micromechanical method, the weighted residual self-consistent method (WRSCM) is developed to study the effective thermal conductivity of two-phase composites with different particle geometries in the presence of a thermal barrier resistance at the interface between constituents. The imperfect interface involves the continuity of the normal flux but allow for a finite temperature differences across the interface. Within the framework of self-consistent scheme, the effective thermal conductivity of two-phase composite is obtained using numerical iterative method on the basis of a surface integral of temperature over the imperfect interfaces. Numerical results show that for the given composite system, due to the existence of an interfacial thermal resistance, the particle geometries have significant impact on the effective thermal conductivity of composites.


Author(s):  
Ayushman Singh ◽  
Srikanth Rangarajan ◽  
Leila Choobineh ◽  
Bahgat Sammakia

Abstract This work presents an approach to optimally designing a composite with thermal conductivity enhancers (TCEs) infiltrated with phase change material (PCM) based on figure of merit (FOM) for thermal management of portable electronic devices. The FOM defines the balance between effective thermal conductivity and energy storage capacity. In present study, TCEs are in the form of a honeycomb structure. TCEs are often used in conjunction with PCM to enhance the conductivity of the composite medium. Under constrained composite volume, the higher volume fraction of TCEs improves the effective thermal conductivity of the composite, while it reduces the amount of latent heat storage simultaneously. The present work arrives at the optimal design of composite for electronic cooling by maximizing the FOM to resolve the stated trade-off. In this study, the total volume of the composite and the interfacial heat transfer area between the PCM and TCE are constrained for all design points. A benchmarked two-dimensional direct CFD model was employed to investigate the thermal performance of the PCM and TCE composite. Furthermore, assuming conduction-dominated heat transfer in the composite, a simplified effective numerical model that solves the single energy equation with the effective properties of the PCM and TCE has been developed. The effective thermal conductivity of the composite is obtained by minimizing the error between the transient temperature gradient of direct and simplified model by iteratively varying the effective thermal conductivity. The FOM is maximized to find the optimal volume fraction for the present design.


2006 ◽  
Vol 306-308 ◽  
pp. 775-780
Author(s):  
Tung Yang Chen

Effective thermal conductivities of composites consisting of curvilinearly anisotropic inclusions with Kapitza thermal contact resistance between the constituents are considered. We show that the effect of these curvilinearly anisotropic inclusions can be exactly simulated by certain equivalent isotropic or transversely isotropic inclusions. Three different micromechanical models are employed to estimate the effective thermal conductivity of the composite. Interestingly, all these methods result in the same simple, closed-form expression.


1998 ◽  
Vol 51 (2) ◽  
pp. 349-360 ◽  
Author(s):  
B. M. Suleiman ◽  
S.E. Gustafsson ◽  
E. Karawacki ◽  
R. Glamheden ◽  
U. Lindblom

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