蘑菇对流预冷的试验研究

通过试验分析了在低温空气强制对流预冷过程中蘑菇传热、传质受气流速度、温度的影响。结果表明:对流预冷比真空预冷重量损失小、无冻伤。作者还用集总参数法建立了含有气化潜热的能量守恒传热微分方程,其数值解与试验吻合。改变参数可预测不同条件下蘑菇降温过程。

An Investigation on Blast Precooling of Mushrooms

In order to get more profit, it is necessary to reduce weight loss of vegetables and fruits during precooling. In this paper, the heat and mass transfer in mushrooms during blast precooling is studied experimentally. Experimental result shows that the relative humidity of cooling air is the main factor which affects the weight loss, the higher the humidity the lesser the weight loss. The result also shows that the cooling rate of mushrooms is dependent on the velocity of cooling air, the faster the air velocity the quicker the cooling rate. To lower the temperature of mushrooms for 20 C by blast precooling, the weight loss is less than 2%, which is only about half of that caused by vacuum precooling. Using lumped parameters method, a heat transfer differential equation is developped, in which the latent heat of moisture evaporation from mushroom surface is considered. Numerical solution of this equation can be used to predict blast precooling of spherical and lump vegetables and fruits.