Numerical Survey of the Melting Driven Natural Convection Using Generation Heat Source: Application to the Passive Cooling of Electronics Using Nano-Enhanced Phase Change Material

2019 ◽  
Vol 12 (2) ◽  
Author(s):  
Hamza Faraji ◽  
Mustapha Faraji ◽  
Mustapha El Alami
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Source ◽  
Phase Change ◽  
Phase Change Material ◽  
Metallic Nanoparticles ◽  
Simple Algorithm ◽  
Bottom Side ◽  
Volume Method ◽  
Change Material

Abstract The present paper reports numerical results of the melting driven natural convection in an inclined rectangular enclosure filled with nano-enhanced phase change material (NePCM). The enclosure is heated from the bottom side by a flush-mounted heat source (microprocessor) that generates heat at a constant and uniform volumetric rate and mounted on a substrate (motherboard). All the walls are considered adiabatic. The purpose of the investigation is analyzing the effect of nanoparticles insertion by quantifying their contribution to the overall heat transfer. Combined effects of the PCM type, the inclination angle and the nanoparticles fraction on the structure of the fluid flow and heat transfer are investigated. A 2D mathematical model based on the conservation equations of mass, momentum, and energy was developed. The governing equations were integrated and discretized using the finite volume method. The SIMPLE algorithm was adopted for velocity–pressure coupling. The obtained results show that the nanoparticles insertion has an important quantitative effect on the overall heat transfer. The insertion of metallic nanoparticles with different concentrations affects the thermal behavior of the heat sink. They contribute to an efficient cooling of the heat source. The effect of nanoparticles insertion is also shown at the temperature distribution along the substrate.

Effect of phase change material wall on natural convection heat transfer inside an air filled enclosure

2017 ◽  
Vol 126 ◽  
pp. 305-314 ◽  
Author(s):  
Abdelouhab Labihi ◽  
Faiçal Aitlahbib ◽  
Hassan Chehouani ◽  
Brahim Benhamou ◽  
Mohammed Ouikhalfan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Convection Heat Transfer ◽  
Natural Convection Heat Transfer ◽  
Convection Heat ◽  
Change Material

Natural Convective Heat Transfer Characteristics of the Bundle Heat Exchanger in the Latent Heat Microcapsulated Phase Change Material Slurry

2016 ◽  
Vol 852 ◽  
pp. 969-976
Author(s):  
Jian Zhang ◽  
Liang Wang ◽  
Yu Jie Xu ◽  
Yi Fei Wang ◽  
Zheng Yang ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Phase Change ◽  
Convective Heat Transfer ◽  
Phase Change Material ◽  
Convective Heat ◽  
Latent Functionally Thermal Fluid ◽  
Potential Applications ◽  
Change Material

As a novel latent functionally thermal fluid, microcapsulated phase change material slurry (MPCMS) has many potential applications in the fields of energy storage, air-conditioning, refrigeration and heat exchanger, etc. In order to investigate the heat storage and heat transfer performance of MPCMS, natural convection in a rectangular enclosure heated by bundle heat exchanger has been studied numerically in this paper. The effects of mass concentration (Cm) of MPCMS, the vertical spaces of bundle heat exchanger on the natural convective heat transfer are investigated. The results indicate that, MPCMS with Cm=30% shows the best natural convectionperformance, and a lower position of bundle heat exchanger can strengthen the natural convection.

Natural Convection With Micro-Encapsulated Phase Change Material

2012 ◽  
Vol 134 (8) ◽  
Author(s):  
R. Sabbah ◽  
J. Seyed-Yagoobi ◽  
S. Al-Hallaj
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Operating Conditions ◽  
Heat Transfer Characteristics ◽  
Transfer Characteristics ◽  
Vertical Walls ◽  
Encapsulated Phase Change Material ◽  
Change Material

This study numerically explores the effect of presence of micro-encapsulated phase change material (MEPCM) on the heat transfer characteristics of a fluid in a rectangular cavity driven by natural convection. The natural convection is generated by the temperature difference between two vertical walls at constant temperatures. The phase change material (PCM) melts in the vicinity of the hot wall and solidifies near the cold wall. Unlike the pure fluids, the heat transfer characteristics of MEPCM slurry cannot be simply presented in terms of corresponding dimensionless controlling parameters such as Rayleigh number. In the presence of phase change particles, the controlling parameters’ values change significantly due to the local phase change. The numerical results show significant increase in the heat transfer coefficient (up to 80%) at the considered operating conditions. This increase is a result of the MEPCM latent heat and the increased volumetric thermal expansion coefficient due to MEPCM volume change during melting.

scholarly journals Thermal management of photovoltaic panel with nano-enhanced phase change material at different inclinations

2021 ◽  
Author(s):  
UNNIKRISHNAN KARTHAMADATHIL SASIDHARAN ◽  
ROHINIKUMAR BANDARU
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Phase Change ◽  
Phase Change Material ◽  
Thermal Management ◽  
Thermal Energy ◽  
Liquid Fraction ◽  
Maximum Enhancement ◽  
Conduction Heat Transfer ◽  
Change Material

Abstract Photovoltaic (PV) panel, coupled with phase change material (PCM), has attracted broad attention for the panel's thermal management. Despite the higher energy storage capability of PCMs, the main disadvantage is their low thermal conductivity which is compensated to an extent with the nano-enhanced PCMs (NEPCMs). In this study, numerical simulations are carried out to compare the natural convection phenomena and thermal response of PV-NEPCM with simple PV-PCM for various tilt angles. CuO nanoparticles with a 4% volume concentration are selected for NEPCM. The thermal performance of PV-NEPCM at inclinations of 0°, 15°, 30°, and 45\(^\circ\) are compared with a simple PV-PCM system. The average temperature of PV, liquid fraction and thermal energy stored in PCM, the PV efficiency are compared for PV-PCM and PV-NEPCM systems. Results show that the loading of nanoparticles increases the conduction heat transfer inside PCM. It has also been shown that at lower inclinations, the use of NEPCM is more effective due to the dominance of conduction heat transfer. At higher tilt angles, natural convection plays a significant role in the heat transfer mechanism inside PCM. By using NEPCM, the maximum decrease in PV temperature of 1.11\(℃\) and maximum improvement in the liquid fraction (7.6%) are achieved when \({\theta }=0^\circ\) compared to simple PCM. Enhancement of thermal energy stored in PCM increases slightly upon adding nanoparticles, and the highest improvement is obtained for \({\theta }=0^\circ .\) Maximum enhancement of PV efficiency is found to be 1.6% for \({\theta }=0^\circ\) inclination on adding nanoparticles at a fraction of 4 vol.%. Keywords: PV, nano-enhanced PCM, nanoparticles, natural convection, liquid fraction.

scholarly journals Study of Thermal Behavior of a Horizontal Two Fins Annular Tube Heat Exchanger with Melting Phase Change Material: Fins Orientation Effects

2021 ◽  
Vol 45 (2) ◽  
pp. 141-151
Author(s):  
Nesrine Boulaktout ◽  
El Hacene Mezaache ◽  
Abdelghani Laouer
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Heat Exchanger ◽  
Phase Change ◽  
Phase Change Material ◽  
Melting Process ◽  
Initial Time ◽  
Tube Heat Exchanger ◽  
Change Material ◽  
Annular Tube

This paper investigates the effect of fins orientations of a horizontal two fins annular tube heat exchanger on enhancing the heat transfer during the melting process of n-eicosane, as phase change material (PCM) used in thermal storage systems. Based on the enthalpy-porosity method, two-dimensional model is performed and solved by Ansys Fluent. The impact of the fins orientation on melting rate, thermal conduction and natural convection, as the angle of the system varied from 0º (vertical fins) to 90º (horizontal fins) are discussed. Numerical predictions are validated by comparison with experimental data and numerical results reported in the literature. Good agreements are achieved. The results show that at initial time of the melting process, the conduction heat transfer is dominant. During the melting process, the heat transfer in the horizontal fins is more effective while the upper half of PCM melts and less effective as the lower half of PCM melts because fin arrangement resists natural convection occurs. However, the effectiveness of heat transfer and convection in the vertical fins is almost constant during the entire melting process. From comparison, better heat transfer performance is achieved with vertical fins system; complete melting was reduced 250% compared to horizontal fins case.

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