Dissertation > Agricultural Sciences > Agricultural Engineering > Agricultural machinery and implements > Initial agricultural product processing machinery > Drying machinery and equipment

The Computer Simulation of Roller Drying for Flaky Agriculture Materials

Author YangYan
Tutor GeZhenYang
School Kunming University of Science and Technology
Course Agricultural Mechanization Engineering
Keywords the roller drying heat and mass transfer rose petals flaky materials computer simulation
CLC S226.6
Type Master's thesis
Year 2011
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This paper is part of the category of agricultural products processing plus agricultural machinery equipment. We employed computer simulation to study the agricultural flaky materials roller drying process.As a key link of agricultural production, agricultural products drying is a key step in the agricultural products process, so improving the technological level of agricultural drying is of great significance for reducing material loss.The drying methods of agricultural materials are mainly as follows:atmospheric hot air drying, heat drying, vacuum freeze drying, microwave drying, infrared drying and osmotic drying, in which atmospheric air drying is widely adopted in the actual production for its big production capacity and to operate easily, improving this method gets more attention, exploring the combined fluidized bed and fixed bed reactor under atmospheric pressure rollers in the dryer and the drying process is in order to provide a new method for drying of agricultural materials.Different agricultural materials have different physical and other properties, which have the different drying characteristics, the different drying processes and equipment were required. Although the empirical methods would guide the research of drying process and equipment, but it often had a great of blindness, so the drying characteristics of materials were researched and analyzed, then, to set up a mathematical model, the drying process were simulated and analyszed by it combined with computer technology, the role and effect of the drying various material in drying process were in-depth study by the different drying method were the foundation and basis that were used for to optimize the design about drying process,to make a reasonable control, and to define the most suitable drying mode of operation.The rose petals were selected to represent the the agricultural flaky materials in this paper, its characteristics about drying were analyszed, the special roller drying equipment were designed. It could recovery the water contained some aromatic ingredients.The features of its structure and working processes is that it make the materials to raised with the rotating roller,then the raised materials were felled from the high place, to contact the hot air, which was similar with the flowed material in fuiled bed drying, which promote the drying medium and material to mixi and increase the surface area of material contact with the drying medium, to enhance heat and mass transfer between gas-solid. The main content of paper as follows.Experiment of the material drying, the experiment included three monothetic-ele ment experiments,which were linked with hot air temperature, rotate speed of roller, and quality, and the orthogonal experiment with the three factors and three levels, the results show that:hot air temperature greatly influence on the drying rate, cons idering the three Factors:drying temperature, rotate speed of roller, the material qua lity, the optimal drying conditions were identified, according to the experimental da ta the dynamic model of drying were fitted and calculate the effective diffusion coe fficient of the material.To study and analysis the movement of flaky materials when it was drying in roller dryer. Movement of materials were discuss by dividing into the rise phases and fall phases, and to establish the mathematical model of the movement about material in the roller dryer,to calculation the time about falling, to determine the scope of work speed.To analysis the heat and mass transfer in roller drying process. The drying process will be divided into a finite number of units by time interval combined with the periodic motion, according to mass balance, energy balance equation o,to research and analysis the material moisture and temperature, air humidity and temperature changes in units, to establish the corresponding mathematical model and the heat and mass transfer mathematical model of transient of materials.To simulate drying process of flaky materials in roller dryer. The simulation program is established by using MATLAB software, which were based on the mathematical model.,to carry out the computer simulation., the simulation results about rose petals compare with the experimental results, the results show that the simulation with a certain accuracy is ture.Results of this study show that:the simulation of flaky materials in roller dryin g could predict the change of materials and air in the roller dryer under the differe nt dry conditions, and the transient temperature distribution and water distribution in flaky material. The results can be used to optimize the structural parameters of roll er equipment and the new process parameters of the roller drying. It has great signi ficance for design and selection of process and equipment.

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