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.

摘要

通过实验测量水和甘油的二元混合物的饱和和过冷池沸腾的传热系数 (HTC)。研究了具有水质量分数的混合物的饱和沸腾${\omega }_{\mathrm{w}}$从$100\mathrm{\%}$到$60\mathrm{\%}$在水平平坦的镀镍表面上，热通量为 50 至$650\mathrm{k}\mathrm{W}{\mathrm{米}}^{-\mathrm{2个}}$在大气压下。过冷沸腾是在过冷度从 0 到$30\mathrm{钾}$在大约 250、450 和$650\mathrm{k}\mathrm{W}{\mathrm{米}}^{-\mathrm{2个}}$. 结果发现，即使对于甘油含量非常低的混合物，混合物效应对饱和沸腾 HTC 也有显着影响，因为观察到 HTC 的显着下降是由于高含量混合物的组成发生细微变化。${\omega }_{\mathrm{w}}$. 测量的 HTC 成功地与 Yagov (1999) 和 Inoue and Monde (2009) 相关性的组合相关联，平均相对误差为$12\mathrm{\%}$. 还提出了一个简单的经验 HTC 相关性。对于过冷沸腾，所有研究的热通量都达到了发展的过冷沸腾状态。对于这种情况，能够预测饱和沸腾 HTC 的相关性被用于预测所有研究浓度、热通量和过冷度的过冷沸腾 HTC。对于含水量较高的混合物，过冷度和液体成分对总 HTC 的影响同样重要。随着混合物中甘油浓度的增加，总 HTC 随着过冷度的增加而降低变得更加显着。