采后果实表面对流换热系数测定

Determination of Heat Transfer Coefficients of Postharvest Fruit

以苹果、黄瓜为实验对象,通过对采后果实热空气处理中表面对流换热系数的实验测定,得到换热实验关联式。结果表明:在相同的热空气温度下,果实表面对流换热系数随空气流速的增大而增大;随果实径向尺寸的增大而减小;采后果实作为生物体,由于自身的蒸腾作用,传热过程中出现了流体的相变,进而导致换热效果显著增强。

A test was applied to determine the heat transfer coefficients of apple and cucumber to obtain the experimental correlation of heat transfer.The results showed that the heat transfer coefficients of fruit increased with the increasing of air velocity,decreased with the increasing of radial dimension of fruit under the same condition of the hot air temperature.The heat exchange efficiency between fruits and hot air was enhanced significantly for the biological transpiration.Phase transition occurred in the process of heat transfer.