Optimization And Numerical Simulation Of Temperature Field Uniformity In Wolfberry Drying Oven

Lycium barbarum vacuum pulse drying has many advantages such as no alkali addition in the drying process,effective removal of bacteria and pesticide residues in the fresh Lycium barbarum,and little environmental pollution.It has become an important process for wolfberry preservation and preservation.The drying process of vacuum pulsation is carried out in a closed drying box with a multilayer Lycium barbarum tray.Therefore,improving the uniformity of temperature distribution in drying box is the key to ensure vacuum pulsation drying of Lycium barbarum.The core component of the drying box is the heat exchanger,and the heat transfer performance of the heat exchanger directly affects drying effect of drying box.Heat exchangers are mainly divided into plate heat exchangers and tube heat exchangers.The two heat exchangers were compared and the heat exchanger with high heat transfer efficiency was selected for analysis.With the help of numerical simulation method,the temperature field in the drying box was studied to provide reasonable theoretical support for the optimization of parameters of the drying box.Combined with the actual working conditions of the drying equipment,the calculation of the wall thickness of the drying box and the selection of heat exchangers were completed.According to the relevant structural parameters of the drying box,a three-dimensional model of the drying box was established,and numerical simulation was carried out by using the computational fluid dynamics software Fluent,The simulation results were compared with the experimental results,verifying the reliability of numerical simulations.And under the condition that other structural parameters of the drying box were kept unchanged,a certain structural parameter was changed independently to analyze the influence of each parameter on the temperature field uniformity of the drying box.Taking the uniformity coefficient of the temperature field of the drying box as the target response value,the simulation test and data collection of four factors including the width of the flow channel of the heat exchange plate,the flow velocity of hot water,the distance of the heat exchange plate and the height of the flow channel of the heat exchange plate were carried out by using the design of experiment.And use the formula to get all the target response values.Then,the response surface method was used to fit the relationship between the input parameters and the output parameters;The significance among the factors affecting the uniformity of temperature field was obtained,and the optimal target response value and the corresponding parameters were obtained.The simulation was carried out again by using this group of parameters,and the results were compared with the original numerical simulation results.It was found that the uniformity of temperature field in the drying box after parameter optimization was significantly improved.