Simulation And Optimization Design And Process Research Of Hot-air Microwave Fluidized Drying Equipment

Microwave drying with a fast drying, high efficiency, low energy consumption has technology advantages, but the dried product uniformity is poor, yield is low; Fluidized bed drying has the advantage of uniform drying dynamic; air drying dehydrated fruit and vegetable processing with mature technology is the most widely used, but the efficiency in the late drying is low, the drying time is long, the energy consumption is high, and the product quality and nutrition preservation rate is low. The fast and efficient microwave drying, fluidized drying dynamic uniform drying, hot air drying high-moisture characteristics combined with the advantages of low cost, is a new joint drying technology-hot air fluidized microwave drying technology. In this paper, microwave drying chamber and the feed energy device optimized design and simulation analysis, design and development of the corresponding hot air fluidized microwave drying equipment, microwave and hot air fluidized carrot drying process tests.Optimized design of microwave drying chamber to determine the microwave drying chamber is rectangular cavity, the cavity dimensions of800×690×600mm, the total number of modes to meet the requirements of106, to meet the requirements of more resonant cavity mode. Ansoft HFSS was used for the wave simulation of the type of the drying chamber opening position, different combinations of the arrangement of the feed opening.The simulation results show that the multi-tube arrangement of the feed-in simulation results are six-sided opening and the cloth best microwave field uniformity is better. Electromagnetic simulation using CST software for the simulation of the same material impact study of different sizes, spacing, and placement of materials with different dielectric constants of the microwave field. The simulation shows that the material is smaller, the smaller the interval when placed more uniform distribution of the microwave field, the dielectric properties of materials the distribution of the microwave field is mainly reflected the impact of the electric field in the extreme, the greater the dielectric constant microwave field strength decreases.The basis of the main components of the device design was analysized, Microwave heating means, hot air heating device, the vibration control means of the apparatus and structure is obtained. The device performance microwave field uniformity and equipment for verification and found that the microwave field uniformity can reach89.4%, with good uniformity. Equipment performance verification test results:microwave output power up to6kW, in the (0.6～6kW) range can be adjusted, hot air power in the (0～4kW) range is adjustable, vibration frequency0～50Hz regulation, the whole structure design parameters to select the correct, safe, reliable, stable performance, easy to operate.Carrots were drying on the quality and texture characteristics of single-factor studies, analysis of microwave technology features of hot air fluidized drying carrot, the results:carrot drying air temperature increases, the sensory quality decreased after the first rise, hot air70℃, the sensory quality of the best; with increasing microwave power, the first rise in sensory quality decreased, the microwave power is10W/g, the sensory quality of the best; after switching point increases moisture content, sensory quality first increased and then decreased when the water content was50%conversion point, the best sensory quality; after rehydration with fresh carrots carrot closest parameter conditions:air temperature70℃, the water content was50%conversion point, microwave.power8W/g. By selecting air temperature, moisture content and conversion point microwave power as independent variables, the application of orthogonal test process optimization of microwave hot air fluidized drying carrot, by studying the following conclusion. The impact of descending order are:air temperature>switching point moisture content>microwave power. Hot air temperature is60℃, the conversion point moisture content of50%, microwave power10W/g, the sensory quality obtain optimal value.