Study On The Mechanism Of Optimizing Heat And Mass Transfer In Drying Process Of Biological Wet Porous Materials

This project has been supported by the National Science Foundation, and placed on "Seed Engineering". Based on the comprehensively description of the biological wet porous material drying study and development, a lot of experimental data obtained and theoretical analysis, engineering practice, this paper has researched the unsteady drying dynamic characteristics, the internal moisture diffusion in the drying process of biological wet porous material. The purpose is to reveal the mechanism of the optimizing heat and mass transfer, develop optimized drying theory, and supply reliable theoretical and technological basis for the design and manufacture of a new type of dryer for industrial use. The main efforts have been concentrated on the following aspects:1. Experimental study: in accordance with the material characteristics, a set of new type of drying experimental facilities has been developed and improved, which consists of a multifunctional fixed bed and a spiral promotion vibrated fluidization bed. By applying different subject intersection, selecting grain, Chinese herb and vegetable seed as typical materials to be dried, this paper has carried out the contrast experiments on the material drying dynamic characteristics and the seed physiology test simultaneously. All these work has supplied the reliable basis of further theoretical study and mathematical model analysis, and the design of a new type of dryer.2. Drying theoretical model: a set of drying theoretical model has been put forward, which consists of the unsteady drying dynamic equation and the internal moisture diffusion model, the drying system performance polynomial model. This set of mathematical model is to describe the drying process characteristics from the heat and mass transfer between the material and the external drying media, internal moisture diffusion, to drying system operation. And the unsteady drying dynamic equation is to analyze the direction of optimizing heat sand mass transfer, and the internal moisture diffusion model is to investigate the mechanism on optimizing of heat and mass transfer, on which to design the rational drying system and organize optimized drying technological process. The polynomial model is to...