Numerical Model of Time-Dependent Gas Flows Through Bed of Granular Phase Change Material

2019 ◽  
Vol 17 (06) ◽  
pp. 1950010 ◽  
Author(s):  
Nickolay A. Lutsenko ◽  
Sergey S. Fetsov

A novel mathematical model and original numerical method for investigating time-dependent gas flows through a bed of granular phase change material (PCM) are proposed and described in detail. Such material is modeled as a porous medium, and continua mechanics method are used for constructing the mathematical model. The numerical method is based on a combination of explicit and implicit finite-difference schemes. Comparison of calculation results with known experimental data demonstrates a very good coincidence. The results of the study can be applied in modeling the thermal energy storage with granular PCM in advanced adiabatic compressed air energy storage and other heat storage devices.

1982 ◽  
Vol 104 (1) ◽  
pp. 19-23 ◽  
Author(s):  
F. E. Moore ◽  
Y. Bayazitoglu

Melting of a phase change material within a spherical enclosure is considered. The phase change material is initially at its saturation temperature. Suddenly the enclosure temperature is increased to a fixed value. The density of the solid is assumed to exceed the density of the liquid, the implication being that the solid continually drops toward the bottom of the shell as melting progresses. This motion of the solid generates a flow field within the liquid. A mathematical model is developed and confirmed by experimental evidence. The interface positions and the temperature profiles for various Stefan and Fourier numbers are determined, and the energy storage characteristics are studied. It is found that the convective effects can be neglected only at small Stefan numbers.


2012 ◽  
Vol 455-456 ◽  
pp. 374-381
Author(s):  
Xiao Qin Sun ◽  
Quan Zhang ◽  
Ying Jun Liu ◽  
Hong Xing Yang ◽  
Lin Feng Zhang ◽  
...  

Energy storage technology is becoming more important nowadays due to use of renewable energy resources. The heat transfer performance of a PCM (phase change material) which is the carrier of energy is the main factor that affects its utilization. This paper presents the thermal characteristics of the PCM-20. An energy storage module is designed based on the numerical calculation results from the MATLAB. Numerical simulation about this module is carried out by CFD software. The simulation results have been compared with the results of numerical calculation and the error between them has been analyzed and discussed.


2018 ◽  
Vol 49 (6) ◽  
pp. 509-528 ◽  
Author(s):  
Orawan Aumporn ◽  
Belkacem Zeghmati ◽  
Xavier Chesneau ◽  
Serm Janjai

Author(s):  
Tonny Tabassum Mainul Hasan ◽  
Latifa Begum

This study reports on the unsteady two-dimensional numerical investigations of melting of a paraffin wax (phase change material, PCM) which melts over a temperature range of 8.7oC. The PCM is placed inside a circular concentric horizontal-finned annulus for the storage of thermal energy. The inner tube is fitted with three radially diverging longitudinal fins strategically placed near the bottom part of the annulus to accelerate the melting process there. The developed CFD code used in Tabassum et al., 2018 is extended to incorporate the presence of fins. The numerical results show that the average Nusselt number over the inner tube surface, the total melt fraction, the total stored energy all increased at every time instant in the finned annulus compared to the annulus without fins. This is due to the fact that in the finned annulus, the fins at the lower part of the annulus promotes buoyancy-driven convection as opposed to the slow conduction melting that prevails at the bottom part of the plain annulus. Fins with two different heights have been considered. It is found that by extending the height of the fin to 50% of the annular gap about 33.05% more energy could be stored compared to the bare annulus at the melting time of 82.37 min for the identical operating conditions. The effects of fins with different heights on the temperature and streamfunction distributions are found to be different. The present study can provide some useful guidelines for achieving a better thermal energy storage system.


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