液体真空蒸发冻结过程的动力学研究

简要介绍了液体物料真空蒸发冻结过程中出现的暴沸、过冷、冻结等实验现象.针对溶液由液相表面蒸发为汽相、由冻干室向冷阱室流动迁移、在冷凝器上凝结的全过程,从质量与能量守恒原理、热力学原理和气体动力学原理出发,建立了完整的数学模型,并以纯水为例进行了模拟计算.同时利用专门组建的实验装置,对纯水的真空蒸发冻结过程开展了实验观测研究,得到整个过程的质量、温度、压力-时间曲线.通过对比理论模拟计算和实验测试的结果,说明了所建立的动力学模型的正确性.

Thermal Dynamical Study of Vacuum Freezing of Liquids

We addressed the complete thermal dynamic processes,such as the boiling,supper-cooling and freezing of liquid materials,in vacuum freezing.The processes,including the vaporization of the solution,its transport from the freeze-drying chamber to the condensation chamber,and its coagulation on the condenser,were modeled,based on the energy and mass conservation principle,as well as the thermodynamic and gas dynamic theories.The newly-developed physical model was tested witha simulation of pure water.In a dedicated setup,the realistic time evolutions of the mass,temperature and pressure were evaluated.The experimental data agree very well with the calculated results.