冻干机冷阱传热性能实验研究

Experimental study on the heat transfer performance of freeze-dryer's cold trap

对影响冻干机冷阱传热性能的两个因素 (冷阱盘管壁面温度和结霜厚度 )进行了实验研究。实验研究表明冷阱壁面温度越低则冷阱捕集效率越高 ;随着霜层厚度的不断增加 ,传热性能将不断下降。对影响冷阱传热的另一个因素—真空度 ,进行了理论分析 ,认为随着冷阱真空度的提高 ,换热强度不断降低 。

An experimental study on the performance of freeze-dryer's cold trap has been carried out under different temperature of the cold trap coil and different frost thickness in the paper. Research results reveal that the capture efficiency of cold trap increases with the decrease of the temperature of cold trap coil, and the overall heat transfer coefficient of the cold trap decreases with the increase of frost accumulation on the surface of the cold trap coil. A theoretical analysis on the convection heat transfer in the cold trap shows that the convection heat transfer decreases with the increase of the degree of vacuum, and the convective heat transfer needn't to be considered when the fluid in the cold trap is in the state of free-molecule flow.