伴随相变的不互溶二元液体混合物的传热 (二)流动传热实验研究

CONVECTIVE HEAT TRANSFER OF IMMISCIBLE TWO LIQUIDS MIXTURE WITH CHANGE OF PHASE PART Ⅱ EXPERIMENTAL STUDAY ON CONVECTIVE HEAT TRANSFER

本文以环已烷为分散相、水为连续相进行了不互溶二元液体混合物的流动传热实验:分析了传热机理;关联了实验数据。对于伴随相变化的不互溶二元液体混合物的流动传热过程。从传热机理上可将其分为四个不同的传热区域。即:液—液、汽—液—液、无相变汽—液和汽—液沸腾四个区域。在汽—液—液区域内,分散相液滴的相变化仅仅起到对连续相加剧湍动的作用,而相变化本身对多相流与壁面的传热无影响.在对单一液滴在另一与之不互溶的连续相中的流体力学及相变过程研究的基础上,本文着重对汽—液—液和无相变汽—液区域内的传热系数进行了无因次数群关联.经验关联式的计算值能够与实验值较好地吻合。

Experiments were made on the heat transfer of immiscible two-liquidmixture with eyclohexane as the dispersed phase and water as the continuous phase. For the convective heat transfer of immiscible two-liquid mixture with change of phase there are four different heat transfer regimes; liquid-liquid, vapour-liquid-liquid, vapour-liquid without phase change and boiling vapour-liquid regimes. The phase change of the dispersed drops itself did not exert any enhancement to heat transfer other than the enhancement to turbulent intensity of the immiscible liquids mixture. Based on the analysis of the hydrodynamic characteristics and phase change process of a single liquid drop vaporizing while rising in a column of another immiscible liquida correlation of heat transfer coefficienta for the regimes of vapour-liquid-liquid andvapour-liquid-liquid without phase change is proposed. The calculated results of heat transfer coefficients from the correlation agree well with the experimental data.