Influence of the Mushy Zone Constant on the Numerical Simulation of the Melting and Solidification Process of Phase Change Materials

Hameter, Michael; Walter, Heimo

doi:10.1016/b978-0-444-63428-3.50078-3

Cited by 29 publications

(6 citation statements)

References 7 publications

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“…Fadl and Eames [21] reported that the numerical predictions are less sensitive to the value of C in regions where heat transfer is dominated by conduction. Assessing the degree of sensitivity of the numerical prediction to the value of C for different materials and boundary conditions is an open question, despite its significance has been emphasised in the literature [21,22,30,38].…”

Section: Introductionmentioning

confidence: 99%

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

2019

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The high degree of uncertainty and conflicting literature data on the value of the permeability coefficient (also known as the mushy zone constant), which aims to dampen fluid velocities in the mushy zone and suppress them in solid regions, is a critical drawback when using the fixed-grid enthalpy-porosity technique for modelling non-isothermal phase-change processes. In the present study, the sensitivity of numerical predictions to the value of this coefficient was scrutinised. Using finite-volume based numerical simulations of isothermal and non-isothermal melting and solidification problems, the causes of increased sensitivity were identified. It was found that depending on the mushy-zone thickness and the velocity field, the solid–liquid interface morphology and the rate of phase-change are sensitive to the permeability coefficient. It is demonstrated that numerical predictions of an isothermal phase-change problem are independent of the permeability coefficient for sufficiently fine meshes. It is also shown that sensitivity to the choice of permeability coefficient can be assessed by means of an appropriately defined Péclet number.

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Section: Introductionmentioning

confidence: 99%

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

2019

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“…Hameter [15], Kumar [16], in their studies, have concluded that the variation in the constant C* has a significant influence on the thermohydraulic behaviour of PCM. C* is a morphological constant (or mushy zone constant) that indicates the melting front's structure and pattern.…”

Section: Momentum Equationsmentioning

confidence: 98%

“…Various kinds [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] of latent heat storage devices have been adopted to conserve energy. Multiple parameters influence the design of these latent heat storage devices.…”

Section: Introductionmentioning

confidence: 99%

Correlations for Melting Time and Melt Fraction for Bottom Charged Tube in Tube Phase Change Material Heat Exchanger

Raj

Sreenivas²,

Prasad

2021

Preprint

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Multiple factors govern the Thermo-hydraulic behaviour of Latent heat storage devices. The correlation among these factors varies from case to case. In this work, a concentric tube in tube latent heat storage system is numerically modelled for the bottom charging case. Fixed grid enthalpy porosity approach is adopted to account for phase change. The numerical model’s independence is achieved by testing mesh size, time step, and maximum iterations per time step. The computational approach is validated against the experimental data. Non-dimensional parameters viz Rayleigh Number (3.04x105 to 65.75 x105), Stefan Number (0.2 to 1), Reynolds Number (600 to 3000), and L/D ratio (2 to 15) are varied in the respective ranges mentioned in parenthesis. Stefan number is found to have a major influence on the Melt Fraction and Melting time, compared to Rayleigh Number and Reynolds Number. Correlations are presented for quantifying the melt fraction and dimensionless melting time.

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“…The steeper the shift of the material's velocity to zero when it solidifies, the higher this number. Extremely high values could make the solution oscillate [9][10].…”

Section: 𝑆 =mentioning

confidence: 99%

Parametric Analysis of a Latent Heat Storage System for Predicting the Charging and Discharging Time

Omlang,

Honra

2024

E3S Web Conf.

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Latent Heat Storages (LHS) are essential for harnessing renewable energy by storing surplus energy for later use. This research aims to enhance the predictability of charging and discharging times in LHS systems, a crucial step for effective energy management and optimizing renewable energy utilization. A comprehensive parametric analysis was conducted using computational fluid dynamics (CFD) to develop correlation equations for forecasting these times under diverse geometric and operational settings. Parameters considered includes the heat transfer fluid (HTF) inlet temperature, phase change material (PCM) thickness-to-length ratio, Reynold’s number, and HTF inlet location. The enthalpy-porosity method and Boussinesq model were employed in numerical simulations to account for natural convection during charging. The influence of the mushy-zone constant on the PCM’s temperature profile was investigated and found to be significant. The bottom HTF injection was found to reduce the charging times, while extending discharging durations. The thickness-to-length ratio of the PCM emerged as the most influential factor, with Reynold’s number exerting the least influence in the cycle. Analysis showed that increasing PCM thickness-to-length ratio consistently led to longer charging time. Four correlations were developed with an impressive average multiple R of 0.999463, signifying high predictability for charging and discharging times.

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Influence of the Mushy Zone Constant on the Numerical Simulation of the Melting and Solidification Process of Phase Change Materials

Cited by 29 publications

References 7 publications

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

Sensitivity of Numerical Predictions to the Permeability Coefficient in Simulations of Melting and Solidification Using the Enthalpy-Porosity Method

Correlations for Melting Time and Melt Fraction for Bottom Charged Tube in Tube Phase Change Material Heat Exchanger

Parametric Analysis of a Latent Heat Storage System for Predicting the Charging and Discharging Time

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