Vacuum Freeze Carnation Color Retention Soften Heat And Mass Transfer Research

How to control biological material in low temperature and low pressure conditions is the most important study on vacuum freeze drying step.It is very important to study on process for the retention of biological materials and nutrients what people need,such as the appearance of purpose.The vacuum freezing process is a phenomenon that occurs in the material,that the water in the plant is cooled condensed and lowered.This method of freezing is different from the previous freezing method of rack coil.And how to control temperature,material size and space pressure will affect effect of products.In this paper,carnation flowers are used as experimental material.And the heat and mass transfer of liquid substances in flowers during vacuum freezing are studied by experiments and numerical simulation.What the color preserving agent and softening agent for fresh carnation flowers is calcium chloride,citric acid and glycerin.The experiment to nine groups of different flowers consists of pre processed,analytical drying operation.We need to distinguish the color retention effect of softening process,and record the corresponding data comparison of different components of solvent on carnations by the assessing colorimetric and color analysis of flowers color quality,color retention.At last,we obtain the optimal softening ratio.The process about carnation leaves of heat transfer is simulated by the energy exchange process.And we can verify the optimal distribution of carnation flowers in the vacuum freezing process by analysis of simulation results,and we can also select another group as comparison.We can get the conclusion of the best group that uniform heat transfer and the faster than another.The process of mass transfer in flower is simulated by Boltzmann method.It can simulate velocity of fluid transmission,and get the law of mass transfer.Porosity was used as a standard to describe the change of velocity and at last,it can describe the internal velocity to analyze the migration process of water in the freeze-drying process.The paper uses the method of experiment and numerical simulation to study carnation softening and color retention of heat and mass transfer.The content verifies the color paper softening formula.We introduce the concept of porosity to test that it is suitable for flowers leaf mass transfer process,and meanwhile using it to describe the process of change rate of porosity.