The Lattice Boltzmann Investigation for the Melting Process of Phase Change Material in an Inclined Cavity

2017 ◽  
Vol 140 (1) ◽  
Author(s):  
Zhonghao Rao ◽  
Yutao Huo ◽  
Yimin Li

The solid–liquid phase change process is of importance in the usage of phase change material (PCM). In this paper, the phase change lattice Boltzmann (LB) model has been used to investigate the solid–liquid phase change in an inclined cavity. Three heat flux distributions applied to the left wall are investigated: uniform distribution, linear distribution, and parabolic symmetry distribution. The results show that for all the heat flux distributions, the slight clockwise rotation of the cavity can accelerate the melting process. Furthermore, when more heat is transferred to the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution) of left wall, clockwise rotation of cavity leads to larger temperature of PCM.

Author(s):  
Zhonghao Rao ◽  
Yutao Huo ◽  
Yimin Li

The solid-liquid phase transition process is of significant importance the widely usage of phase change material (PCM), including in thermal energy storage and maintaining working temperature. In this paper, a phase change lattice Boltzmann (LB) model has been established to investigate the effects of inclining angle on the melting process in a cavity filled with PCM, considering three kinds of heat flux distribution: uniform distribution, linear distribution and parabolic symmetry distribution. The simulations results show that for all the heat flux distributions, the slight clockwise rotation of cavity is able to accelerate the melting process. Furthermore, when more heat is transported into the cavity through the middle part (parabolic symmetry distribution) or bottom part (linear distribution), the effects of cavity clockwise rotation on temperature field are more than that of anticlockwise rotation.


Author(s):  
Horacio Ramos-Aboites ◽  
Abel Hernandez-Guerrero ◽  
Salvador M. Aceves ◽  
Raul Lesso-Arroyo

This paper presents the results of a -numerical transient model for phase change in a storage cell filled with a phase change material (PCM). Phase change occurs under the presence of natural convection. The PCM is encapsulated in a cylindrical energy storage cell. Two cases of PCM melting are analyzed, (1) the surface temperature of the bottom half of the cylindrical cell is kept at a constant temperature, which is higher than the melting temperature of the PCM, and (2) a fluid flows under the cell with an inlet temperature that is higher than the melting point of the PCM. The results show the evolution of the solid-liquid interface, isotherms and flow lines during the melting process.


2018 ◽  
Vol 7 (4.5) ◽  
pp. 587
Author(s):  
Jay R. Patel ◽  
Manish K. Rathod

Latent heat energy storage using macro encapsulated phase change material is an emerging technique for thermal energy storage applica- tions. The main aim of the present investigation is to investigate the melting process of phase change material filled in different shaped configurations. The selected different cavities are square, circular and triangular. A mathematical model based on convection dominated melting is required to be developed, especially in view of the complex flow geometries encountered in such problems. Thus, an attempt has been made to develop a model using ANSYS Fluent 16.2 to investigate the heat transfer rate and solid-liquid interface visualization of PCM filled in different shapes of cavity. It is found that triangular shaped macro encapsulated PCM melts faster than square and circu- lar shaped encapsulated PCM.   


2018 ◽  
Vol 8 (9) ◽  
pp. 1627 ◽  
Author(s):  
Yong Wang ◽  
Jingmin Dai ◽  
Dongyang An

This paper investigates the melting process of phase change material in a rectangular cavity at different inclination angles. Paraffin is used as a phase change material in this study. One side of the cavity is heated while the other sides are considered to be adiabatic. The investigated angles of inclination include 0° (bottom horizontal heating), 30°, 60°, 90° (vertical heating), 120°, 150° and 180° (top horizontal heating). Shapes of the solid liquid interface and temperature variations during the melting process were discussed for all the inclination angles. The results reveal that the inclination angles have a significant impact on the melting behavior of paraffin. As the angle increases from 0° to 180°, the complete melting time increases non-linearly.


Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3254 ◽  
Author(s):  
Túlio Nascimento Porto ◽  
João M. P. Q. Delgado ◽  
Ana Sofia Guimarães ◽  
Hortência Luma Fernandes Magalhães ◽  
Gicelia Moreira ◽  
...  

The development of thermal energy storage systems is a possible solution in the search for reductions in the difference between the global energy supply and demand. In this context, the ability of some materials, the so-called phase change materials (PCMs), to absorb and release large amounts of energy under specific periods and operating conditions has been verified. The applications of these materials are limited due to their low thermal conductivity, and thus, it is necessary to associate them with high-conductivity materials, such as metals, to make the control of energy absorption and release times possible. Bearing this in mind, this paper presents a numerical analysis of the melting process of a PCM into a triplex tube heat exchanger (TTHX) with finned copper tubes, which allowed for the heat transfer between a heating fluid (water) and the phase change material to power a liquid-desiccant air conditioning system. Through the analysis of the temperature fields, liquid fractions, and velocities, as well as the phase transition, it was possible to describe the material charging process; then, the results were compared with experimental data, which are available in the specialized literature, and presented mean errors of less than 10%. The total required time to completely melt the PCM was about 105.5 min with the water being injected into the TTHX at a flow rate of 8.3 L/min and a temperature of 90 °C. It was observed that the latent energy that accumulated during the melting process was 1330 kJ, while the accumulated sensitive energy was 835 kJ. The average heat flux at the internal surface of the inner tube was about 3 times higher than the average heat flux at the outer surface of the TTHX intermediate tube due to the velocity gradients that developed in the internal part of the heat exchanger, and was about 10 times more intense than those observed in the external region of the equipment.


2018 ◽  
Vol 140 (10) ◽  
Author(s):  
Yutao Huo ◽  
Zhonghao Rao

A new lattice Boltzmann (LB) model to solve the phase change problem, which is based on the enthalpy-transforming model has been developed in this paper. The problems of two-region phase change, natural convection of air, and phase change by convection are solved to verify the present LB model. In two-region phase change, the results of the present LB model agree well with that of analytical solution. The benchmark solutions are applied to evaluate the present LB model in natural convection of air and phase change material (PCM) as well. The results show that the present LB model is able to simulate the temperature distribution and capture the location of solid–liquid interface in the cavity accurately. Moreover, the present LB model is effective in computing owing to the fact that no iterations are necessary during the simulations.


2020 ◽  
Vol 22 (4) ◽  
pp. 1439-1452
Author(s):  
Mohamed L. Benlekkam ◽  
Driss Nehari ◽  
Habib Y. Madani

AbstractThe temperature rise of photovoltaic’s cells deteriorates its conversion efficiency. The use of a phase change material (PCM) layer linked to a curved photovoltaic PV panel so-called PV-mirror to control its temperature elevation has been numerically studied. This numerical study was carried out to explore the effect of inner fins length on the thermal and electrical improvement of curved PV panel. So a numerical model of heat transfer with solid-liquid phase change has been developed to solve the Navier–Stokes and energy equations. The predicted results are validated with an available experimental and numerical data. Results shows that the use of fins improve the thermal load distribution presented on the upper front of PV/PCM system and maintained it under 42°C compared with another without fins and enhance the PV cells efficiency by more than 2%.


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