Numerical Modelling of the Effective Thermal Conductivities of Composite Materials

2011 ◽  
Author(s):  
Zhi Zhu He ◽  
Jing Liu
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Thermal Effects ◽  
Transfer Equation ◽  
Heat Transfer Equation ◽  
Transfer Enhancement ◽  
Conduction Heat Transfer ◽  
Nanoparticle Shape ◽  
Alternate Direction ◽  
Implicit Finite Difference

Nanoparticles with high thermal conductivity are often impregnated within fluids or biological tissue for heat transfer enhancement. Prediction of effective thermal conductivity of such nanocomposite plays an important role in evaluating thermal effects induced by nanoparticles. In this article, an order parameter is introduced to characterize the domain of nanoparticles so that a unified conduction heat transfer equation is established. An effective numerical technology alternate direction implicit finite difference is adopted to solve the heat transfer equation. The present approach could potentially account for the effect of nanoparticle shape and size.

scholarly journals Temperature distribution in the three-layered upper mantle beneath a continent

2021 ◽  
Vol 2119 (1) ◽  
pp. 012006
Author(s):  
A G Kirdyashkin ◽  
A A Kirdyashkin ◽  
A V Borodin ◽  
V S Kolmakov
Keyword(s):  
Heat Transfer ◽  
Temperature Distribution ◽  
Convective Heat Transfer ◽  
Upper Mantle ◽  
Lower Mantle ◽  
Transfer Equation ◽  
Horizontal Layer ◽  
Heat Transfer Equation ◽  
Continental Lithosphere ◽  
Conduction Heat Transfer

Abstract Temperature distribution in the upper mantle underneath the continent, as well as temperature distribution in the lower mantle, is obtained. In the continental lithosphere, the solution to the heat transfer equation is obtained in the model of conduction heat transfer with inner heat within the crust. To calculate the temperature distribution in the upper and lower mantle, we use the results of laboratory and theoretical modeling of free convective heat transfer in a horizontal layer heated from below and cooled from above.

scholarly journals Assessment of homotopy perturbation method in nonlinear convective-radiative non-Fourier conduction heat transfer equation with variable coefficient

2011 ◽  
Vol 15 (suppl. 2) ◽  
pp. 263-274 ◽  
Author(s):  
Mohsen Torabi ◽  
Hessameddin Yaghoobi ◽  
Seyfolah Saedodin
Keyword(s):  
Heat Transfer ◽  
Perturbation Method ◽  
Transfer Equation ◽  
Homotopy Perturbation Method ◽  
Heat Transfer Equation ◽  
Conduction Heat Transfer ◽  
Homotopy Perturbation ◽  
Runge Kutta Method ◽  
Engineering Problems ◽  
Specific Heat Coefficient

Analytical solutions play a very important role in heat transfer. In this paper, the He's homotopy perturbation method (HPM) has been applied to nonlinear convective-radiative non-Fourier conduction heat transfer equation with variable specific heat coefficient. The concept of the He's homotopy perturbation method are introduced briefly for applying this method for problem solving. The results of HPM as an analytical solution are then compared with those derived from the established numerical solution obtained by the fourth order Runge-Kutta method in order to verify the accuracy of the proposed method. The results reveal that the HPM is very effective and convenient in predicting the solution of such problems, and it is predicted that HPM can find a wide application in new engineering problems.

Study of the boundary layer heat transfer of nanofluids over a stretching sheet: Passive control of nanoparticles at the surface

2015 ◽  
Vol 93 (7) ◽  
pp. 725-733 ◽  
Author(s):  
M. Ghalambaz ◽  
E. Izadpanahi ◽  
A. Noghrehabadi ◽  
A. Chamkha
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Boundary Layer ◽  
Nusselt Number ◽  
Heat Transfer Enhancement ◽  
Base Fluid ◽  
Stretching Sheet ◽  
Volume Fraction ◽  
Enhancement Ratio ◽  
Transfer Enhancement

The boundary layer heat and mass transfer of nanofluids over an isothermal stretching sheet is analyzed using a drift-flux model. The relative slip velocity between the nanoparticles and the base fluid is taken into account. The nanoparticles’ volume fractions at the surface of the sheet are considered to be adjusted passively. The thermal conductivity and the dynamic viscosity of the nanofluid are considered as functions of the local volume fraction of the nanoparticles. A non-dimensional parameter, heat transfer enhancement ratio, is introduced, which shows the alteration of the thermal convective coefficient of the nanofluid compared to the base fluid. The governing partial differential equations are reduced into a set of nonlinear ordinary differential equations using appropriate similarity transformations and then solved numerically using the fourth-order Runge–Kutta and Newton–Raphson methods along with the shooting technique. The effects of six non-dimensional parameters, namely, the Prandtl number of the base fluid Prbf, Lewis number Le, Brownian motion parameter Nb, thermophoresis parameter Nt, variable thermal conductivity parameter Nc and the variable viscosity parameter Nv, on the velocity, temperature, and concentration profiles as well as the reduced Nusselt number and the enhancement ratio are investigated. Finally, case studies for Al2O3 and Cu nanoparticles dispersed in water are performed. It is found that increases in the ambient values of the nanoparticles volume fraction cause decreases in both the dimensionless shear stress f″(0) and the reduced Nusselt number Nur. Furthermore, an augmentation of the ambient value of the volume fraction of nanoparticles results in an increase the heat transfer enhancement ratio hnf/hbf. Therefore, using nanoparticles produces heat transfer enhancement from the sheet.

PDMS nanocomposites for heat transfer enhancement in microfluidic platforms

Lab on a Chip ◽  
2014 ◽  
Vol 14 (17) ◽  
pp. 3419-3426 ◽  
Author(s):  
Pyshar Yi ◽  
Robiatun A. Awang ◽  
Wayne S. T. Rowe ◽  
Kourosh Kalantar-zadeh ◽  
Khashayar Khoshmanesh
Keyword(s):  
Heat Transfer ◽  
Thermal Conductivity ◽  
Heat Transfer Enhancement ◽  
Transfer Enhancement ◽  
Microfluidic Platforms

This work introduces a method to enhance the thermal conductivity of PDMS microfluidic platforms through the use of PDMS/Al2O3 nanocomposites.

Systems Actuated by Shape Memory Alloys: Identification and Modeling

2021 ◽  
Vol 1 (2) ◽  
pp. 12-20
Author(s):  
Najmeh Keshtkar ◽  
Johannes Mersch ◽  
Konrad Katzer ◽  
Felix Lohse ◽  
Lars Natkowski ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Mathematical Model ◽  
Constitutive Model ◽  
Shape Memory Alloys ◽  
Numerical Simulations ◽  
Shape Memory ◽  
Transfer Equation ◽  
Mechanical Parameters ◽  
Heat Transfer Equation ◽  
The Mathematical Model

This paper presents the identification of thermal and mechanical parameters of shape memory alloys by using the heat transfer equation and a constitutive model. The identified parameters are then used to describe the mathematical model of a fiber-elastomer composite embedded with shape memory alloys. To verify the validity of the obtained equations, numerical simulations of the SMA temperature and composite bending are carried out and compared with the experimental results.

scholarly journals Laplace transform series expansion method for solving the local fractional heat-transfer equation defined on Cantor sets

2016 ◽  
Vol 20 (suppl. 3) ◽  
pp. 777-780
Author(s):  
Huan Sun ◽  
Xing-Hua Liu
Keyword(s):  
Heat Transfer ◽  
Laplace Transform ◽  
Series Expansion ◽  
Transfer Equation ◽  
Expansion Method ◽  
Cantor Sets ◽  
Heat Transfer Equation ◽  
Local Fractional Calculus ◽  
The Laplace Transform ◽  
Series Expansion Method

In this paper, we use the Laplace transform series expansion method to find the analytical solution for the local fractional heat-transfer equation defined on Cantor sets via local fractional calculus.

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