Various ways to take into account density change in solid–liquid phase change models: Formulation and consequences

Dallaire, Jonathan; Gosselin, Louis

doi:10.1016/j.ijheatmasstransfer.2016.07.045

Cited by 26 publications

(26 citation statements)

References 24 publications

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“…Through mass conservation, an extra term that depends on the shape of the container and the rate of density changes, will be shown to appear on the thermal balance at the interface. To the authors knowledge, this term has been overlooked or neglected by other authors [18,19,20,22,23]. We will show that depending on the mechanical properties of the container, this term represents a small perturbation, or it may have a significant contribution to the thermal energy absorbed by the PCM.…”

Section: Introductionmentioning

confidence: 77%

“…Then, the effects of density changes in the solid, caused by the pressure increment within the PCM can be neglected. In this work, the assumption of incompressible phases [22,23] will be relaxed by coupling the mass conservation of the liquid–solid system with the thermal balance at the interface. First, the melted mass of solid ΔMs over a small time interval Δt, can be obtained by realizing that ΔMs is transformed into liquid.…”

Section: Resultsmentioning

confidence: 99%

“…The numerical and semi-analytical solutions will be validated through the isochoric limit, by probing the phase transition from the isobaric (constant pressure) to the isochoric regimes. The thermo-mechanical models proposed by other authors [18,19,20,22,23] are well behaved close to the isobaric regime; however, it will be shown that these models are unable to reproduce the isochoric limit. Finally, the contributions from density changes to the thermal energy absorbed, will be determined by comparing the proposed solutions with the predictions from other authors.…”

Section: Introductionmentioning

confidence: 85%

“…The thermo-mechanical model presented in this paper has been elaborated through the key idea of total and local mass conservation in a spherically confined PCM. Our proposal leads to an estimation of the sensible heat, latent heat, and total heat absorbed by the PCM that presents significant differences when compared to the predictions of other authors [18,19,20,22,23]. Through mass conservation, an extra term that depends on the shape of the container and the rate of density changes, will be shown to appear on the thermal balance at the interface.…”

Section: Introductionmentioning

confidence: 91%

“…These proposals constitute a first approach for explaining the behavior of PCMs when encapsulated by different materials. Other authors [22,23], study the one-dimensional liquid–solid phase transition, by coupling the PCM to a linear spring and assuming incompressible phases. This assumption neglects the effects of density variations on the behavior of the phase transition.…”

Section: Introductionmentioning

confidence: 99%

See 4 more Smart Citations

Effects of Pressure-Induced Density Changes in the Thermal Energy Absorbed by a Micro-Encapsulated Phase-Change Material

Hernández-Cooper

2019

Molecules

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Density changes produced by pressure increments during melting of a spherically confined phase-change material have an impact on the thermal energy absorbed by the heat storage unit. Several authors have assumed incompressible phases to estimate the volume change of the phase-change material and the thermal balance at the liquid–solid interface. This assumption simplifies the problem but neglects the contribution of density changes to the thermal energy absorbed. In this work, a thermal balance at the interface that depends on the rate of change of the densities and on the shape of the container is found by imposing total mass conservation. The rigidity of the container is tuned through the coupling constant of an array of springs surrounding the phase-change material. This way, the behavior of the system can be probed from the isobaric to the isochoric regimes. The sensible and latent heat absorbed during the melting process are obtained by solving the proposed model through numerical and semi-analytical methods. Comparing the predictions obtained through our model, it is found that even for moderate pressures, the absorbed thermal energy predicted by other authors can be significantly overestimated.

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