Numerical and experimental study of melting in a spherical shell

Assis, E.; Katsman, L. M.; Ziskind, G.; Letan, R.

doi:10.1016/j.ijheatmasstransfer.2006.10.007

Cited by 417 publications

(148 citation statements)

References 24 publications

(45 reference statements)

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“…Much of the earlier work was performed using the Enthalpy-Porosity method and the VOF method, and have been gradually improved. In order to extend these methods to three phases as in the present study, a combination of melting and free surface tracking is required (Assis et al, 2007;Ganaoui et al, 2002;Jeong et al, 2010;Kamnis & Gu, 2005). For this reason, in the present study numerical model including scalar transport and a source term in the governing equation is considered, and these combined methods are applied to investigate the phenomena during a melting and falls-off process of suspended liquified matter beneath the wire.…”

Section: Wwwintechopencommentioning

confidence: 99%

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

Kim¹,

Hossain²,

Kim³

et al. 2011

Two Phase Flow, Phase Change and Numerical Modeling

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Section: Wwwintechopencommentioning

confidence: 99%

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

Kim¹,

Hossain²,

Kim³

et al. 2011

Two Phase Flow, Phase Change and Numerical Modeling

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“…In contrast to the most applications the solid PCM is not fixed within macro-capsules and settles down during melting, resulting in close contact melting. To take account of the settling Assis et al [6] implemented a low Darcy term value. Therefore, the velocity in the solid PCM is not suppressed completely resulting in a slow settling solid.…”

Section: Introductionmentioning

confidence: 99%

“…Computational fluid dynamics (CFD) simulations allow a more detailed view on the melting within macro-capsules. Therefore, Asako et al [5], Assis et al [6] and Rösler [7] developed different CFD models to study the melting of a PCM with settling in a capsule. In general, modelling the moving inter-facial boundary in melting and solidification has been of greater importance in many industrial and research applications.…”

mentioning

confidence: 99%

Numerical modelling of melting and settling of an encapsulated PCM using variable viscosity

et al. 2016

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demand and decrease pollution. This thermal energy can be stored and delivered back when needed.Latent heat thermal energy storage (LHTES) has become interesting to store thermal energy with a high storage density in a small temperature range. However, the low charging and discharging power of these units is due to the poor thermal conductivity of the phase change material (PCM) [2]. Macro-encapsulation of PCM may enhance the thermal distribution in thermal storage units by increasing the heat transfer area between the heat transfer fluid (HTF) and PCM. Macro-encapsulated PCM are already installed in different applications like ventilated façade [3], thermal storage units [4] etc. But different experimental set-ups are required to investigate and improve the efficiency of a thermal storage system. Therefore numerical modelling and simulation is employed to improve the efficiency and to reduce experimental efforts. Different simplified approaches exist to analyse macro-encapsulated PCM but they are limited to specific applications and are also less accurate in predicting the performance of thermal storage units. Computational fluid dynamics (CFD) simulations allow a more detailed view on the melting within macro-capsules. Therefore, Asako et al. [5], Assis et al. [6] and Rösler [7] developed different CFD models to study the melting of a PCM with settling in a capsule. In general, modelling the moving inter-facial boundary in melting and solidification has been of greater importance in many industrial and research applications. The Eulerian fixed grid approach is most common to model moving boundary interfaces for a solid-liquid phase change. Crank [8] delivered an initial idea of modelling moving boundary problems by considering just the diffusion in a phase change problem. Later different researchers have developed efficient methods of computing phase change problems including the convection in the liquid phase [9][10][11]. Solid-liquid Abstract Thermal energy storage units using macroencapsulated PCM in industrial and residential applications are contemporary due to better efficiency during charging and discharging. This article focuses on numerical modelling of the melting process in a macro-encapsulated PCM. Accounting the non-linear enthalpy-temperature relation and ramping down the velocity in solid phase is therefore fundamental. In the present article the variable viscosity method is implemented to ramp down the solid velocity and allow settling of the solid phase. This complete numerical model of melting and settling of PCM in a capsule is implemented in OpenFOAM. The numerical results for different solid viscosities are validated with experiments and show good agreement. The influence of the solid viscosity value and the pressure-velocity convergence is studied. It is observed that the pressure-velocity convergence only plays a greater role in the case where the computation of the exact solid velocity is required.

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“…Since there is no universal value for A mush in modelling by Enthalpy-Porosity method, different values have been used in different systems [19,26]. As clearly shown in [27], melt fraction and solid shape evolution are highly dependent on A mush , and there exists an optimum value of A mush for each system.…”

Section: Governing Equationsmentioning

confidence: 99%

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

Kim

Hossain

Nakamura

2013

International Journal of Heat and Mass Transfer

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Numerical simulations are performed in order to examine the time-dependent melting, and heavily deforming processes of phase change material (PCM) subjected to local heating. By comparing cases with and without deformation, the impact of the inclusion of a deformation model is firstly addressed to understand what influences the precise melting behavior. Mass, momentum and energy conservation equations are solved in a 2-D system based on a fixed grid by means of a finite volume method. The Volume of Fluid (VOF) method and the Enthalpy-Porosity method are applied to model the deformable liquid-gas interface and the melting processes, respectively. Results successfully show the melting, subsequent deformation and dropping-off behavior of the molten PCM. It is found that the inclusion of the deformation model enhances the melting owing to the increase of the total received heat; namely, widening of the contact area at the melting front and induced flow motion inside molten PCM improve the heat transfer toward the melting front. Parametric studies by varying the applied Stefan number so as to change the surface tension are also made to ensure the above-mentioned enhancement mechanism is universally applicable.

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Numerical and experimental study of melting in a spherical shell

Cited by 417 publications

References 24 publications

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

A Numerical Study on Time-Dependent Melting and Deformation Processes of Phase Change Material (PCM) Induced by Localized Thermal Input

Numerical modelling of melting and settling of an encapsulated PCM using variable viscosity

Numerical study of melting of a phase change material (PCM) enhanced by deformation of a liquid–gas interface

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