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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

TEMPERATURE-DEPENDENT DYNAMIC VISCOSITY OF TWO SUGAR ALCOHOLS AND THEIR BINARY EUTECTIC MIXTURE AS HEAT STORAGE MATERIALS

Get access (open in a dialog) DOI: 10.1615/IHTC16.tpm.022421
pages 8637-8644

Résumé

Sugar alcohols and their binary eutectic mixtures have been proposed as promising phase change material candidates as applied to low-to-medium temperature (373.15-523.15 K) latent heat storage. The dynamic viscosity is deemed to be important transport property of the candidate materials, which is directly related to the heat storage/retrieval of latent heat storage systems. In this work, the temperature-dependent dynamic viscosities of two pure sugar alcohols (d-mannitol and d-dulcitol) and their binary eutectic mixture (70 mol% d-mannitol) were measured experimentally over a wide temperature range (393.15-533.15 K). At each temperature point of interest, measurements were undertaken at various shear rates from 0.1 s-1 to 300 s-1. Upon establishing the viscosity-temperature curves, the Arrhenius model was adopted to correlate the dynamic viscosity as a function of temperature by curve fitting. The activation energies Eη of the pure sugar alcohols are determined based on curving fitting. It was found that the pure and mixture sugar alcohols, either in the melt or in the supercooled liquid state, show non-Newtonian behaviors at the full shear rate range. The dynamic viscosities decrease exponentially with increasing the temperature, and the values of d-mannitol and d-dulcitol are 36.0 mPas and 18.5 mPas, respectively at their melting temperatures. D-mannitol present a higher activation energy of 41418.77 J/mol than that of d-dulcitol (38505.54 J/mol).