Numerical investigations of using carbon foam/PCM/Nano carbon tubes composites in thermal management of electronic equipment W.G. Alshaer a , S.A. Nada a,⇑ , M.A. Rady b , Cedric Le Bot c , Elena Palomo Del Barrio c a Mechanical Engineering Department, Benha Faculty of Engineering, Benha University, Benha, P.O. 13512, Egypt b Mechanical Engineering Department, Faculty of Engineering at Helwan University, Helwan, P.O. 11421, Egypt c Université de Bordeaux, Laboratoire TREFLE, Esplanade des Arts et Métiers, 33405 Talence, France article info Article history: Received 22 August 2014 Accepted 20 October 2014 Keywords: Thermal management Electronic equipment PCM Nano carbon tubes abstract A numerical investigation of predicting thermal characteristics of electronic equipment using carbon foam matrix saturated with phase change material (PCM) and Nano carbon tubes as thermal manage- ment modules is presented. To study the effect of insertion of RT65 and Nano carbon tubes in carbon foam matrices of different porosities, three different modules; namely Pure CF-20, CF20 + RT65, and CF-20 + RT65/Nano carbon modules are numerically tested at different values of carbon foam porosities. Mathematical model is obtained using volume averaging technique based on single-domain energy equa- tion and a control volume based numerical scheme. Interfacial effects influencing heat transfer process at enclosure wall, module surface and different interfacial surfaces within the composite have been addressed. Governing equations have been solved using a CFD code (Thétis, http://thetis.enscbp.fr). Mathematical model is validated by comparing its prediction with previous experimental measurements for pure CF-20 foam and CF-20 + RT65 composite modules. The model is used to predict thermal charac- teristics of CF-20 + RT65/Nano carbon tubes composite as a thermal management modules. Results reveal that insertion of RT65/MWCNTs in CF-20 leads to a 11.5% reduction in the module surface temperature for carbon foam porosities less than 75%. The reduction decrease to 7.8% for a porosity of 88%. Numerical results of transient and steady state temperature histories at different depths within the module are com- pared with previous experimental data and fair agreement is obtained. Ó 2014 Elsevier Ltd. All rights reserved. 1. Introduction Porous media has been widely used for thermal management (TM) of many engineering applications especially electronic equip- ment [1,2]. Main advantage of a porous system in such applications is its high surface area-to-volume ratio which leads to enhanced heat transport and miniaturization of thermal systems. Foam materials is a highly permeable porous medium characterized by the presence of two or more phases. One of these phases is solid phase and the other can be fluid or just void spaces. In open cell metal or carbon foams, void spaces are connected to each other leading to high permeability. Effective thermal conductivity, inter- facial surface area, and permeability are the properties that control performance of thermal management modules and heat sink. Open cell metal foams have favorites values of these properties which make them highly recommended as a heat sink for thermal man- agement of electronic devices. On the other hand phase change materials (PCMs) are widely recommended for thermal management of electronic devices sub- jected to high heat densities and cyclic temperature variations. Absorbing and storing thermal energy using PCMs are typically used to reduce temperature variations of components that are subjected to periodically varying boundary conditions. Thermal diffusivity of phase change materials is an important property con- trolling heat transfer characteristics of PCMs. Since it determines the ability of PCM material to conduct thermal energy relative to its ability to store energy. Low thermal conductivity of PCM has been a major concern in view of the widely adopted and stringent requirement to store/ release (charge/discharge) thermal energy over a desired time per- iod. Consequently, enhancement of thermal conductivity of PCMs has been a major focus of thermal energy storage researches. Combining PCMs of low thermal conductivity with highly conductive materials is a logical solution to come up with new material processing with enhanced effective thermal conductivity. Placement of metal fillers, foams, wools into the PCM has been investigated and practiced in the last two decades. http://dx.doi.org/10.1016/j.enconman.2014.10.045 0196-8904/Ó 2014 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. Tel.: +20 1066611381. E-mail address: samehnadar@yahoo.com (S.A. Nada). Energy Conversion and Management 89 (2015) 873–884 Contents lists available at ScienceDirect Energy Conversion and Management journal homepage: www.elsevier.com/locate/enconman