Theoretical and numerical analysis on phase change materials (PCM): A case study of the solidification process of erythritol in spheres

Ehms, José Henrique Nazzi; Oliveski, Rejane De Césaro; Rocha, Luíz Alberto Oliveira; Biserni, Cesare

doi:10.1016/j.ijheatmasstransfer.2017.11.124

Cited by 56 publications

(11 citation statements)

References 32 publications

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“…In such domains, convection heat transfer affects the shape of the solid along the process. The main characteristic detected in the solidification process is the formation of a solid layer, whose thickness increases gradually from the heat transfer surface [49,54]. The solidification rate is reduced throughout the process, with its effect observed through the smaller variation of the liquid fraction in the final stages.…”

Section: Solidification Processmentioning

confidence: 99%

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Fixed Grid Numerical Models for Solidification and Melting of Phase Change Materials (PCMs)

et al. 2019

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Phase change materials (PCMs) are classified according to their phase change process, temperature, and composition. The utilization of PCMs lies mainly in the field of solar energy and building applications as well as in industrial processes. The main advantage of such materials is the use of latent heat, which allows the storage of a large amount of thermal energy with small temperature variation, improving the energy efficiency of the system. The study of PCMs using computational fluid dynamics (CFD) is widespread and has been documented in several papers, following the tendency that CFD nowadays tends to become increasingly widespread. Numerical studies of solidification and melting processes use a combination of formulations to describe the physical phenomena related to such processes, these being mainly the latent heat and the velocity transition between the liquid and the solid phases. The methods used to describe the latent heat are divided into three main groups: source term methods (E-STM), enthalpy methods (E-EM), and temperature-transforming models (E-TTM). The description of the velocity transition is, in turn, divided into three main groups: switch-off methods (SOM), source term methods (STM), and variable viscosity methods (VVM). Since a full numerical model uses a combination of at least one of the methods for each phenomenon, several combinations are possible. The main objective of the present paper was to review the numerical approaches used to describe solidification and melting processes in fixed grid models. In the first part of the present review, we focus on the PCM classification and applications, as well as analyze the main features of solidification and melting processes in different container shapes and boundary conditions. Regarding numerical models adopted in phase-change processes, the review is focused on the fixed grid methods used to describe both latent heat and velocity transition between the phases. Additionally, we discuss the most common simplifications and boundary conditions used when studying solidification and melting processes, as well as the impact of such simplifications on computational cost. Afterwards, we compare the combinations of formulations used in numerical studies of solidification and melting processes, concluding that “enthalpy–porosity” is the most widespread numerical model used in PCM studies. Moreover, several combinations of formulations are barely explored. Regarding the simulation performance, we also show a new basic method that can be employed to evaluate the computing performance in transient numerical simulations.

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Section: Solidification Processmentioning

confidence: 99%

“…The temperature interval in continuous properties phase change is commonly approximated to an equivalent T m to simplify and include parameters in the analysis, as well as apply boundary conditions, perform calculations, and obtain results. The most common and simplest approximation used in works [48,49] is given by:…”

Section: Solidification Processmentioning

confidence: 99%

Fixed Grid Numerical Models for Solidification and Melting of Phase Change Materials (PCMs)

et al. 2019

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“…The mathematical model used for solving the problem consists of the conservation of mass, momentum and energy equations, according to the treatment illustrated in Ref. [21]. It is assumed as unsteady, laminar and incompressible flow.…”

Section: Mathematical and Numerical Modelmentioning

confidence: 99%

“…In this type of thermal storage unit, spheres filled with PCM are deposited inside a tank in which the fluid bathes the spheres, establishing various heat transfer processes that occur simultaneously [8]. The topic of PCM melting have been widely treated in literature both experimentally [9][10][11][12][13] and numerically [14][15][16][17][18][19][20][21].…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation on phase change materials (PCM): The melting process of erythritol in spheres under different thermal conditions

Raymundo

Oliveski

Rocha

et al. 2018

International Journal of Mechanical Sciences

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“…[18‐20]. Other constructal designs for the heat transfer with phase change material (PCM) could be seen in Nazzi Ehms et al 21 …”

Section: Introductionmentioning

confidence: 99%

Constructal design of multiscale elliptic tubes in crossflow

Mustafa

Elqadir

2020

Heat Trans

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The optimal configuration of two-scale elliptic tubes in crossflow is found on the basis of the constructal design. The larger tubes are installed inside a domain of fixed length and height. In the same domain, smaller tubes are inserted between the larger tubes in the entrance region at the mid leading edge to leading edge distance of the larger tubes. The spacing between the larger tubes, the semiminor axis of the larger tubes, the major axis of the smaller tubes, and the semiminor axis of the smaller tubes are varied inside the domain freely to find the optimal configuration. There are two optimal configurations: one without the smaller tubes and the other with the presence of the smaller tubes. Both the larger and the smaller tubes are heated at a constant surface temperature. The flow is induced by a fixed pressure difference. The equations for steady, laminar, twodimensional, and incompressible flow are solved by finite volume method. In the absence of the smaller tubes, the range of Bejan number (dimensionless pressure drop) is Be 10 < < 10 3 5 , and in the presence of the smaller tubes, Bejan number is Be = 10 5 . The range of the dimensionless larger tubes semiminor axis is 0.1 ≤ B ≤ 0.4. Air is used to cool the row of the tubes with Prandtl number equal to 0.7. The results show that for different semiminor axes of the larger tubes, the heat transfer rate is enhanced when the smaller tubes are placed between the larger tubes. K E Y W O R D SBejan number, constructal design, crossflow, elliptic tubes

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Theoretical and numerical analysis on phase change materials (PCM): A case study of the solidification process of erythritol in spheres

Cited by 56 publications

References 32 publications

Fixed Grid Numerical Models for Solidification and Melting of Phase Change Materials (PCMs)

Fixed Grid Numerical Models for Solidification and Melting of Phase Change Materials (PCMs)

Numerical investigation on phase change materials (PCM): The melting process of erythritol in spheres under different thermal conditions

Constructal design of multiscale elliptic tubes in crossflow

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