The Property And Applied Research Of Microwave Vacuum Drying Process

Microwave vacuum drying is a new drying method, in which the water molecules of materials placed in alternating electric field move more acutely after being polarized, and the friction between water molecules is also more acute. Frictional heat buildup accelerate the evaporation of surface moisture of materials resulting in the generation of temperature gradient and moisture gradient between internal and external of materials, consequently the transfer of moisture from interior to exterior is accelerated, through which we attain the object of drying. But because of the great influence of parameter such as microwave efficiency, degree of vacuum, drying time, material property etc on quality of dying product during drying process, it is greatly important to have a rational apprehend to microwave vacuum drying.This thesis aims to develop microwave vacuum drying technique, to perform heat transfer and mass transfer analysis, and to establish mathematical model of heat transfer and mass transfer. Wherewith longan and carrot as the analysis object, the influence of drying parameter on drying property during drying process is analyzed, and is applied in food drying. This problem derives from Guangdong province agricultural machine institute drying equipment center, and purposes reducing drying time, improving products' drying quality, and raising drying efficiency.In this paper, we first introduce laboratoryscale microwave vacuum drying equipment, whose key features include that the material going to be dried can roll along with turntable in resonant cavity with the result of avoiding the nonhomogeneity of microwave heating, microwave efficiency can be regulated, and we can have real-time observation on materials' drying state.In this article, we study the technological process of microwave vacuum drying. Wherewith longan and carrot as the analysis object, it researches the primary process of microwave vacuum drying, and acquires drying technological curve of above-mentioned materials. In order to study the influence of drying procedure...