真空冷冻干燥机中冷阱结霜特性的研究

在真空冷冻干燥装置中,冷阱是用来捕集从物料中升华出来的水蒸汽的主要设备.由于冷阱处于低温低压的环境下,物料中升华出来的水蒸气在冷阱冷壁面上从汽态直接凝华成霜而抽除.但是,目前国内外有关低温低压下冷壁面结霜特性的研究很少,这对于研究冷阱的传热传质问题和改进冻干装置带来了难度.本文以冷阱表面的霜和干燥室内的物料为研究对象,引用动压测量技术对物料的升华速率进行了试验研究.同时采用实时摄像法对冷阱表面的结霜过程进行监测,并对霜层内的温度梯度进行分析,进而根据传热问题的傅立叶定律得到霜层的导热系数.

Experimental Study on Performance of Frost on Cold-trap Used by Vacuum Freeze-daying Machine

In vacuum freeze-drying machine,Cold-trap is the main equipment which is used to catch water vapor that is sublimated from freeze materiel.Under low temperature and low-pressure condition,water vapor directly becomes frost on cold-trap.But there is very limited frost characteristic study on cold surface under low temperature and low-pressure condition.At present,it is difficult to research the heat and mass transfer problem on cold-trap and to improve freeze-drying equipments.In this paper,frost on cold-tra...