【摘要】 运用自行研制的真空冷冻实验台,对水、糖水溶液和盐水溶液进行真空冻结,实时检测液体沸腾及冻结过程中样品温度随室内压力变化的曲线,分析了冻结过程中温度与压力的关系,并比较了不同样品的降温速率,及同一样品不同部位的降温速率。结果显示:沸腾过程中,纯水沸腾的时间比盐水和糖水的早,但纯水的最大降温速率比盐水、糖水的小;沸腾降温过程中水、盐水和糖水的液面、中部和底部的降温速率相差不大,上部略高,中部次之,底部略低。更多还原

【Abstract】 Using the self-developed vacuum freeze test-bed,water,sugar and salt aqueous solution were vacuum freezed.The relation between temperatures and the pressure was real-time detected in the process of freezing,the cooling rate of different samples and different parts of the same sample were compared.The results showed that:in the boiling process,the boiling time of water was earlier than salt and sugar,but the biggest cooling rate of water was smaller than saline and sugar;in the cooling process,the cooling rate of water,salt and sugar were no remarkable difference.更多还原