The Design And Study On A Five-layer Banding Net Flowing Drying System For Onion

Aiming at the current market requirements for dring fruits and vegetables,and the status of the multilayer mesh equipment for drying fruits and vegetables in china, a five-layer meshes and cross-flow drying system especially for onion was designed, which enabled the mesh self-cleaning and controlling the temperature and time by segmentation and partition. This design was based on the onion drying characteristics, and combined with the dry theories. The hot air vertically through the material layers of onion to achieve a continuous dring process to dry it through the running convey or belt,and there was a fluctuating temperature field in the onion forward direction where the hot air heat and material could transfer the heat-exchange,by which the drying and productivity efficiency for onion were improved, so as to providean effective support for the development of fruits and vegetables drying industry. The main work is as follows:1. Starting from the principle of belt drier, determine the structure of the belt drying machine, drying machine box structure design, transmission network, transmission system, air supply system, etc;2. According to the drying characteristic curve, and dry onion theory, determine the process parameters of drying machine, including evaporation; The first and second two drying stage of thermal load calculation; The dry air consumption, fan selection, heat exchanger design, the determination of conveyor mesh belt, etc;3. Based on the structure of the mesh belt dryer and dry heat transfer, set up five layer mesh belt type through drying mathematical model of drying machine;4. Using the software Gambit to construct the model of drying oven, and carries on the grid, defined boundary conditions at the same time, and then the grid file to import the Fluent software, choose the appropriate turbulence model, and define the porous medium model, numerical calculation for drying chamber internal flow field;5. Using the Fluent software numerical calculation, the result of the analysis of the mesh belt dryer drying oven inside the distribution of flow field, for later drying system provided a reference for performance improvement.