Modeling of nonisothermal heat and moisture transfer in capillary-porous media in periodic microwave heating

2007 ◽  
Vol 80 (1) ◽  
pp. 1-10 ◽  
Author(s):  
N. N. Grinchik ◽  
P. V. Akulich ◽  
A. L. Adamovich ◽  
P. S. Kuts ◽  
S. P. Kundas
Author(s):  
O. P. Dvoryaninova ◽  
A. V. Sokolov

The effectiveness of drying is largely determined by the ability to quickly manage this process and maintain the regime parameters at a given level. At the heart of any control system is a mathematical description of the process. The paper discusses the process of drying secondary products of fish cutting, as an object of possible modeling and mathematical description of complex physical phenomena of heat and mass transfer. To simulate the processes of heat and moisture transfer, a method based on the generally accepted equations of heat and moisture transfer A.V. Lykova is used. For the convenience of modeling and repeated computer experiments, the computer program "Program for modeling the drying of fish products with additional microwave heating" in the language of Object Pascal in the integrated programming environment Borland Delphi 7 was developed. The program is designed to simulate the drying process of fish products by solving the problem of heat - and moisture transfer on a cubic grid, taking into account the combined heating technology (convective and microwave heating). The program can be used to optimize the drying modes and parameters of the microwave source. In the text of the program, the thermophysical parameters can be given to solve the problem of heat and moisture transfer, the geometric parameters and structure of the fish parts, the parameters of the microwave source. In the process of computer experiment on drying products from fish, the program regularly displays on the computer screen the graphs and cartograms of the spatial distribution of humidity and temperature. The main technical characteristics of the program: the number of grid nodes for solving the problem of heat and moisture transfer: 50 x 50 x 40; the approximate time of one computer experiment is about 5 minutes.


2021 ◽  
Vol 264 ◽  
pp. 01038
Author(s):  
Normakhmad Ravshanov ◽  
Istam Shadmanov ◽  
Kurash Kubyashev ◽  
Sanjar Khikmatullaev

A mathematical model, numerical algorithm, solution, and results of the computational experiment on a computer are developed to predict the process of heat and moisture transfer in porous media, taking into account such factors as the internal heat and moisture release of a porous natural product on the example of raw cotton and its products of hulling, seeds of various crops. It also considers the effect of temperature and moisture content changes in the environment on the storage and drying of porous materials. In this study, the developed mathematical support of the object under research makes it possible to predict the change in temperature and moisture content at arbitrary points of the porous body and serves to prevent the loss of quality and spontaneous combustion of materials under solar radiation and to analyze and make managerial decisions. Based on the method of coordinate-wise splitting, a numerical algorithm for calculating three-dimensional heat and moisture transfer problems in areas of the parallelepiped type is presented. An implicit second-order difference scheme for calculating the required functions is presented. Based on the numerical calculations performed, it was established that moisture and heat transfer and their exchange with the environment occurs in the upper layers of the cotton pile; in the inner layers, there is an increase in temperature and moisture due to the respiration of raw cotton and its seeds, which depends on the degree of moisture of the raw cotton and their products of hulling.


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