强迫与混合对流条件下水流顺掠冰柱传热特性

Heat transfer characteristics of water flowing along icicle under forced and mixed convection

通过实验研究了对流与混合对流条件下水流顺掠冰柱融化过程的相界面移动规律及传热特性。改变冰柱初始尺寸、初始冰柱温度、水流速度与温度等参数,采用工业摄像机记录了冰柱相界面的移动规律,构建了影像实验数据与冰柱相界面传热系数之间的映射关系。通过对实验结果的分析与讨论,获得结论如下:不同速度条件下的平均相界面位置变化趋势相似,相界面随时间呈单调递减幂函数形式变化;平均对流换热系数随水流速度或水流温度的增加而增大,且平均对流换热系数随时间呈递增趋势变化;在不同水流速度或水流温度条件下,Nu随着Gr/Re2先增大经过最高点后再减小;获得了水流顺掠冰柱融化过程Nu与Gr、Re、Pr及Ste之间的经验关联式。

Experiment is conducted to study The heat characteristics and moving regulation of phase change interface in the progress of water flowing along icicle under forced and mixed convection The mapping relationship between the experimental data and the heat transfer coefficient in phase change interface of icicle is established.With various initial dimensions of icicle,initial temperatures in icicle,velocities and temperatures of water,moving regulation of phase change interface of icicle is recorded using industrial cameras The results show that,The variation trend of each location of phase change interface is similar with different velocities,and the location of phase change interface decreases with time in a form of power function;the average convective heat transfer coefficient increase over time with the increase of velocity and temperature of water,with different velocities and temperatures of water,at first Nu increases steadily with Gr/Re 2 ,however it witnesses a fall trend after reach to the peak point.Empirical correlation of Nu 、Gr 、Re 、Prand Ste is established.