Numerical Modelling of Natural Convection Driven Melting for an Inclined/Finned Rectangular Enclosure

2016 ◽  
Author(s):  
Moe Kabbara ◽  
Ali C. Kheirabadi ◽  
Dominic Groulx
Keyword(s):  
Phase Change ◽  
Numerical Study ◽  
Melting Rate ◽  
Experimental Results ◽  
Mushy Region ◽  
Dodecanoic Acid ◽  
Storage Unit ◽  
Inclination Angles ◽  
The One ◽  
The Impact

This paper presents a numerical study aimed at understanding the impact of the mushy zone constant, Amush, on simulated phase change heat transfer with varying geometries (inclination angles, and fin additions). This parameter is found in the Carman-Koseny equation, which is used in the modified heat capacity-porosity formulation for modeling phase change; this approach models fluid flow within the mushy region as flow through a porous medium. The melting of dodecanoic acid inside a rectangular thermal storage unit was simulated in COMSOL Multiphysics 4.4 with Amush being varied for each geometry. The predicted numerical melt front positions were directly compared to published experimental results [18–20]. Results have shown that the influence of Amush on the melting rate of the PCM is reduced with increasing inclination angles of the enclosure; where the melt interface is perpendicular to the direction of gravity. This has been attributed to the reduced velocity magnitudes that appear near the melt interface in such geometries. The addition of the fins showed that near the fin region Amush does not play an important role. However, it was observed that the model over predicts the velocity near the fin in the one fin model, which caused a mismatch between numerical and experimental results.

scholarly journals Numerical Simulation of the Impact of the Heat Source Position on Melting of a Nano-Enhanced Phase Change Material

Nanomaterials ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1425
Author(s):  
Tarek Bouzennada ◽  
Farid Mechighel ◽  
Kaouther Ghachem ◽  
Lioua Kolsi
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Phase Change Material ◽  
Numerical Study ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Commercial Code ◽  
Tube Position ◽  
The Impact ◽  
Change Material

A 2D-symmetric numerical study of a new design of Nano-Enhanced Phase change material (NEPCM)-filled enclosure is presented in this paper. The enclosure is equipped with an inner tube allowing the circulation of the heat transfer fluid (HTF); n-Octadecane is chosen as phase change material (PCM). Comsol-Multiphysics commercial code was used to solve the governing equations. This study has been performed to examine the heat distribution and melting rate under the influence of the inner-tube position and the concentration of the nanoparticles dispersed in the PCM. The inner tube was located at three different vertical positions and the nanoparticle concentration was varied from 0 to 0.06. The results revealed that both heat transfer/melting rates are improved when the inner tube is located at the bottom region of the enclosure and by increasing the concentration of the nanoparticles. The addition of the nanoparticles enhances the heat transfer due to the considerable increase in conductivity. On the other hand, by placing the tube in the bottom area of the enclosure, the liquid PCM gets a wider space, allowing the intensification of the natural convection.

scholarly journals Role of honeycomb structure in improving the melting process of a phase change material inside a latent heat storage unit

2021 ◽  
Vol 19 ◽  
pp. 589-592
Author(s):  
M. Hariss ◽  
◽  
M. El Alami ◽  
A. Gounni
Keyword(s):  
Heat Transfer ◽  
Phase Change ◽  
Numerical Study ◽  
Melting Process ◽  
Honeycomb Structure ◽  
Melting Time ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
The Impact

In this work, a numerical study is performed to analyze the impact of honeycomb structure on heat transfer within the PCM. The modeling is based on a transient calculation making it possible to analyze the phase change of the paraffin using the commercial software "Fluent" based on the enthalpy-porosity model. The results showed that the impregnation of a metal matrix in a rectangular enclosure helps to decrease the melting time and thus improve the heat transfer within the PCM.

scholarly journals Breccia interlayer effects on steam-assisted gravity drainage performance: experimental and numerical study

2021 ◽  
Author(s):  
Qichen Zhang ◽  
Xiaodong Kang ◽  
Huiqing Liu ◽  
Xiaohu Dong ◽  
Jian Wang
Keyword(s):  
Numerical Simulation ◽  
Oil Recovery ◽  
Oil Sands ◽  
Numerical Study ◽  
Middle Part ◽  
Experimental Results ◽  
Production Performance ◽  
Peak Oil ◽  
Steam Chamber ◽  
The Impact

AbstractCurrently, the reservoir heterogeneity is a serious challenge for developing oil sands with SAGD method. Nexen’s Long Lake SAGD project reported that breccia interlayer was widely distributed in lower and middle part of reservoir, impeding the steam chamber expansion and heated oil drainage. In this paper, two physical experiments were conducted to study the impact of breccia interlayer on development of steam chamber and production performance. Then, a laboratory scale numerical simulation model was established and a history match was conducted based on the 3D experimental results. Finally, the sensitivity analysis of thickness and permeability of breccia layer was performed. The influence mechanism of breccia layer on SAGD performance was analyzed by comparing the temperature profile of steam chamber and production dynamics. The experimental results indicate that the existence of breccia interlayer causes a thinner steam chamber profile and longer time to reach the peak oil rate. And, the ultimate oil recovery reduced 15.8% due to much oil stuck in breccia interlayer areas. The numerical simulation results show that a lower permeability in breccia layer area has a serious adverse impact on oil recovery if the thickness of breccia layer is larger, whereas the effect of permeability on SAGD performance is limited when the breccia layer is thinner. Besides, a thicker breccia layer can increase the time required to reach the peak oil rate, but has a little impact on the ultimate oil recovery.

Numerical Study of Phase Change Influence on Wave Impact Loads in LNG Tanks on Floating Structures

2018 ◽  
Author(s):  
Matthieu Ancellin ◽  
Laurent Brosset ◽  
Jean-Michel Ghidaglia
Keyword(s):  
Natural Gas ◽  
Phase Change ◽  
Numerical Study ◽  
Model Tests ◽  
Impact Loads ◽  
Wave Impact ◽  
Floating Structures ◽  
Physical Phenomena ◽  
The Impact ◽  
Phase Phase

Understanding the physics of sloshing wave impacts is necessary for the improvement of sloshing assessment methodology based on sloshing model tests, for LNG membrane tanks on floating structures. The phase change between natural gas and liquefied natural gas is one of the physical phenomena involved during a LNG wave impact but is not taken into account during sloshing model tests. In this paper, some recent numerical and analytical works on the influence of phase change are summarized and discussed. For the impact of an ideally shaped wave, phase change influences two different steps of the impact in different ways: during the gas escape phase, phase change leads to a higher impact velocity; for entrapped gas pockets, phase change causes a reduction of the pressure in the gas pocket. However, this influence is quantitatively small. The generalization to more realistic wave shapes (including e.g. liquid aeration) should be the focus of future works.

scholarly journals Transmission of Impact Vibration on Concrete and Mortar Sheets

2015 ◽  
Vol 2015 ◽  
pp. 1-6 ◽  
Author(s):  
Carlos Morón ◽  
Alfonso García ◽  
Daniel Ferrández ◽  
Víctor Blanco
Keyword(s):  
Building Materials ◽  
Detection System ◽  
Experimental Results ◽  
Acoustic Characteristics ◽  
Vibration Detection ◽  
Alternative System ◽  
Theoretical Predictions ◽  
The One ◽  
The Impact ◽  
Impact Vibration

The present work exposes an alternative system for detecting vibrations generated by impact on concrete and mortar sheets. In order to carry out the tests it is necessary to implement a system of measurement different than the one proposed by the current UNE EN 140-7. This system consists of an amplifier and a striking device that is also able to measure the deformation of the material once the impact has been produced. This system is able to detect variations in transmission of vibration at the same frequency between the various building materials employed, after establishing a relationship between the theoretical predictions and the experimental results. Thus, this system could be used as a vibration detection system and as an alternative method of standardization of materials against their acoustic characteristics.

scholarly journals Impact of Tube Bundle Placement on the Thermal Charging of a Latent Heat Storage Unit

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1289
Author(s):  
Mohammad Ghalambaz ◽  
Amir Hossein Eisapour ◽  
Hayder I. Mohammed ◽  
Mohammad S. Islam ◽  
Obai Younis ◽  
...  
Keyword(s):  
Heat Transfer ◽  
General Circulation ◽  
Liquid Fraction ◽  
Tube Bundle ◽  
Melting Rate ◽  
Heat Transfer Fluid ◽  
Storage Unit ◽  
Latent Heat Storage ◽  
Four Levels ◽  
The Impact

The melting process of a multi-tube’s thermal energy storage system in the existence of free convection effects is a non-linear and important problem. The placement of heated tubes could change the convective thermal circulation. In the present study, the impact of the position of seven heat exchanger tubes was systematically investigated. The energy charging process was numerically studied utilizing liquid fraction and stored energy with exhaustive temperature outlines. The tubes of heat transfer fluid were presumed in the unit with different locations. The unit’s heat transfer behavior was assessed by studying the liquid fraction graphs, streamlines, and isotherm contours. Each of the design factors was divided into four levels. To better investigate the design space for the accounted five variables and four levels, an L16 orthogonal table was considered. Changing the location of tubes could change the melting rate by 28%. The best melting rate was 94% after four hours of charging. It was found that the tubes with close distance could overheat each other and reduce the total heat transfer. The study of isotherms and streamlines showed the general circulation of natural convection flows at the final stage of melting was the most crucial factor in the melting of top regions of the unit and reduces the charging time. Thus, particular attention to the tubes’ placement should be made so that the phase change material could be quickly melted at both ends of a unit.

Numerical study of the melting and resolidification of the substrate during the impact of a ceramic droplet in a plasma spraying process

2019 ◽  
Vol 88 (2) ◽  
pp. 20901 ◽  
Author(s):  
Mouloud Driouche ◽  
Tahar Rezoug ◽  
Mohammed El Ganaoui
Keyword(s):  
Numerical Model ◽  
Phase Change ◽  
Solid Phase ◽  
Numerical Study ◽  
Solid Substrate ◽  
Navier Stokes ◽  
Droplet Spreading ◽  
Substrate Melting ◽  
Volume Method ◽  
The Impact

The substrate melting can significantly improve the properties of plasma spray coatings. Indeed the adhesion of the projected particles to the substrate can be ameliorated by the substrate melting. In this article, a numerical model is developed to study the dynamics of fluids and heat transfer with liquid/solid phase change during impact of a fully melted alumina particle on an aluminum solid substrate, taking into account of the substrate melting. The model is based on solving the Navier-Stokes and energy equations with liquid / solid phase change. These equations are coupled with the fluid of volume method (VOF), to follow the free surface of the particle during its spreading and solidification. The finite volume method is used to discretize the equations in a 2D axisymmetric domain. A comparison with the published experimental results was carried out to validate this numerical model. Simulations were performed for different initial droplet diameters to study its effect on droplet spreading as well as on substrate melting. It has been observed that the substrate melting begins before the droplet spreads completely; the substrate melting reaches its maximum when the droplet is close to its total solidification. Droplet spreading and substrate melting are more important for large sizes droplets.

scholarly journals Thermal Charging Optimization of a Wavy-Shaped Nano-Enhanced Thermal Storage Unit

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1496
Author(s):  
Mohammad Ghalambaz ◽  
S.A.M. Mehryan ◽  
Ahmad Hajjar ◽  
Mohammad Yacoub Al Shdaifat ◽  
Obai Younis ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Phase Change ◽  
Volume Fraction ◽  
Thermal Storage ◽  
Wave Number ◽  
Storage Unit ◽  
Charging Time ◽  
Phase Change Heat Transfer ◽  
The Impact

A wavy shape was used to enhance the thermal heat transfer in a shell-tube latent heat thermal energy storage (LHTES) unit. The thermal storage unit was filled with CuO–coconut oil nano-enhanced phase change material (NePCM). The enthalpy-porosity approach was employed to model the phase change heat transfer in the presence of natural convection effects in the molten NePCM. The finite element method was applied to integrate the governing equations for fluid motion and phase change heat transfer. The impact of wave amplitude and wave number of the heated tube, as well as the volume concertation of nanoparticles on the full-charging time of the LHTES unit, was addressed. The Taguchi optimization method was used to find an optimum design of the LHTES unit. The results showed that an increase in the volume fraction of nanoparticles reduces the charging time. Moreover, the waviness of the tube resists the natural convection flow circulation in the phase change domain and could increase the charging time.

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