Saturated and subcooled pool boiling heat transfer in mixtures of water and glycerin

ABSTRACT

Heat transfer coefficient (HTC) was experimentally measured for saturated and subcooled pool boiling of binary mixtures of water and glycerin. Saturated boiling was studied for mixtures with water mass fractions ${\omega }_{\mathrm{w}}$ from $100\mathrm{\%}$ to $60\mathrm{\%}$ on horizontal flat nickel-plated surfaces at heat fluxes from 50 to $650\mathrm{k}\mathrm{W}{\mathrm{m}}^{-2}$ at atmospheric pressure. Subcooled boiling was investigated in the range of subcooling from 0 to $30\mathrm{K}$ at heat fluxes of approximately 250, 450 and $650\mathrm{k}\mathrm{W}{\mathrm{m}}^{-2}$. It was found that mixture effects have a significant impact on saturated boiling HTC even for mixtures with very low content of glycerin as significant drops of HTC were observed for subtle changes in composition for mixtures of high ${\omega }_{\mathrm{w}}$. Measured HTC was successfully correlated with the combination of Yagov (1999) and Inoue and Monde (2009) correlations with a mean relative error of $12\mathrm{\%}$. A simple empirical HTC correlation is also proposed. For subcooled boiling, developed subcooled boiling regime was reached for all investigated heat fluxes. For this regime, correlations, which were able to predict HTC for saturated boiling, were employed to predict subcooled boiling HTCs for all investigated concentrations, heat fluxes and subcoolings. Effect of subcooling and effect of liquid composition on total HTC were of the same importance for mixtures with higher water content. With the increase in concentration of glycerin in the mixture, decrease in total HTC with increasing subcooling became more significant.

KEYWORDS:

• Pool boiling
• saturated boiling
• subcooled boiling
• heat transfer coefficient
• water–glycerin mixture
• nickel-plated surface

Acknowledgments

This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic under OP RDE grant number CZ.02.1.01/0.0/0.0/16_019/0000753 “Research centre for low-carbon energy technologies,” by the Grant Agency of the Czech Technical University in Prague, grant number SGS20/119/OHK2/2T/12 “Transport Phenomena in Multiphase Systems” and by the Slovenian Research Agency, program number P2-0223, project number J2-2486 “Enhanced boiling heat transfer utilising hierarchical functionalized surfaces (eHEATs).”

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No potential conflict of interest was reported by the author(s).

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

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Funding

This work was supported by the Ministry of Education, Youth and Sports of the Czech Republic [CZ.02.1.01/0.0/0.0/16_019/0000753]; Slovenian Research Agency [P2-0223 (J2-2486)]; Czech Technical University in Prague [SGS20/119/OHK2/2T/12].