Study Of Heat And Mass Transfer Mechanism Based On Microwave Drying Biological Materials

For a long time, the study of heat and mass transfer mechanism has always a key of develop based on microwave drying biological material Microwave drying is a kind of typical dielectric drying method, in alternating electromagnetic field, the polarization of water molecules high-speed friction material movement and generating heat. In the material, the temperature and moisture of gradient from inside to outside is formed. Because of many factors affect microwave drying, so the study of these factors on the microwave drying of material drying characteristics influence of microwave drying technology rapid development has a very important significance.At first, the elementary of microwave drying, the concept and characteristics of microwave, the principle of microwave drying and the theory of heat and mass transfer used in microwave drying is been introduced. And around the internal energy of microwave, microwave drying of material properties is simulated and analyzed.Secondly, using Lamber's theory, the calculation formula of per unit volume of microwave absorbed is founded on during drying cylinder material.using MATLAB software, the influence of the microwave power input, material size, dielectric constant of material absorbed microwaves can is analyzed systematically, concluded that increase microwave power, reduce material thickness, improve dielectric loss factor to material absorbed microwaves could.Finally, Using the theory J-Fourier heat transfer and FICK diffusion microwave drying cylinder material of heat and mass transfer equation is established, and by using the finite element method of differential equation is discretized. Analysis on the same radius, same thickness of each node temperature and humidity, it is concluded that the change law of nodes, far from materials center temperature rises more slower, dry base wet content smaller, Also on the comparison and analysis of the different power, frequency, materials, wind speed, air relative wet content on average temperature and average dry moisture content changes over time, for microwave drying reasonably select these factors are provided.