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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

SOLID-LIQUID PHASE CHANGE AND THERMAL CONDUCTIVITY OF ERYTHRITOL AS A HEAT STORAGE MATERIAL: A MOLECULAR DYNAMICS STUDY

Get access (open in a dialog) DOI: 10.1615/IHTC16.nmt.022420
pages 7181-7188

Abstract

Molecular dynamics (MD) simulation is performed to elucidate the microscale mechanisms of solid-liquid phase change and heat conduction of erythritol. Four force fields are tested for the prediction of density of erythritol at various temperature points of interest. As compared to the measured values, the applicability of GROMOS force field is verified and this force field is adopted in the following simulations. The microscale melting process of erythritol is simulated using interface/NPT method. The temperature corresponding to a sudden volume increase of the simulated system is identified as the melting point (about 400 K), which agrees with the measured value of 392±1 K. Due to lowering of the nucleation free energy barrier by introducing a solid-liquid interface, this method is exhibited to have a better performance in simulating the microscale melting process than the direct heating method on solid erythritol. Moreover, non-equilibrium MD simulation is performed to study the microscale heat conduction between erythritol molecules. The thermal conductivity of liquid erythritol, which is predicted to lie between 0.33~0.35 W/mK and consistent with the measured value of 0.33±0.02 W/mK on bulk erythritol, is found to have a negligible dependence on the size of the simulated system because of the random orientation of erythritol molecules in the liquid phase. The heat conduction in solid erythritol is impacted by finite system size owing to the ordered crystalline structure and phonon modes. In contrast to the measured values, the value of thermal conductivity in solids is underestimated to be about 0.62 W/mK as a result of the imperfect lattice model.