Simulation Of Physical Field In Hot Air Drying Room Based On COMSOL And Design About Dynamic Drying Device

Grass material of hot air drying is a complicated heat transfer and mass transfer process.The required drying environment and conditions are often provided by professional drying systems.And as an important part of the drying system,the internal structure of the drying room and the design of the supporting devices can not only improve the uniform distribution of the physical field in the drying space,optimize the drying quality of grass materials,but also effectively improve the drying efficiency.In order to improve the uniformity of the physical field in the hot air drying room,the structure optimization of the drying room and the design of supporting devices are often carried out based on the uniformity of the distribution of wind velocity and temperature in the drying room.In this thesis,for the TGS-2 solar-heat pump combined drying system,the distribution characteristics of the physical field in the drying room are analyzed under the conditions of no-load and loaded alfalfa.Using the COMSOL Multiphysics simulation platform,the numerical simulation of the wind velocity field and temperature field in the drying room was completed.After the drying test,the method of numerical simulation and parameter setting was determined,and the structure of the drying room was optimized.A dynamic drying device was designed to improve the drying quality and efficiency of grass materials,and the rationality of its structure was verified by test.The main research content is as follows:(1)In the TGS-2 solar heat pump combined drying system,the no-load and load tests of the drying room were carried out,the uneven coefficients of the wind velocity field and temperature field in the drying room were obtained,and the influence of the placement position of grass materials on the drying rate was analyzed.(2)The simulation model is established according to the test parameters,and COMSOL numerical simulation analysis is carried out.Comparing the simulation results with the test results,it is found that the installation position of the existing air inlet and outlet in the drying room is the main reason for the uneven distribution of flow field in the drying room.(3)Based on the test and simulation results,the structure of the drying frame in the drying room is optimized,and the dynamic drying device is designed and developed.The movement of four conveyor belts driven by a single motor according to the adjustable conveying angle is realized,which greatly improves the contact area between grass materials and hot air during drying,and achieves the effect of improving the drying uniformity.(4)The results show that the dynamic drying method can improve the drying uniformity of grass materials.At the same time,it is found that when the rotating frame of the dynamic drying device is inclined on the same side,the dynamic drying effect of grass materials is the best.