Design And Research Of Continuous Infrared Hot Air Combined Dryer

Alfalfa is an excellent forage with rich nutritional value.In order to further study the drying situation of Alfalfa in Inner Mongolia Autonomous Region,the method of infrared and hot air combined drying was adopted in this paper.Infrared drying technology is a relatively new drying method at present.After drying,it has less impact on the quality of agricultural materials,higher drying efficiency and energy saving characteristics.In recent years,it has been widely used in the field of drying.At present,most of the infrared drying equipment adopt fixed structure,in the drying process,the material can not be turned over,resulting in uneven drying of agricultural materials.Therefore,in order to dry alfalfa quickly,it is necessary to design an infrared hot air dryer to dry alfalfa.The design principle of the dryer is that the four conveyor belts in the drying box form a rectangle by high and low superposition,and the conveyor belt forms a reciprocating circulation structure,so that alfalfa can move back and forth in the drying box;the infrared heating pipe is arranged above the conveyor belt to heat the alfalfa;two centrifugal fans are installed above the drying box,and the wind speed can be adjusted manually;the temperature is controlled the system consists of a single chip microcomputer and a temperature sensor to ensure the drying temperature in the drying oven.The mechanical structure design and physical production of the infrared belt dryer were completed.The drying rate and energy consumption of alfalfa were studied through experiments.The flow field and temperature field in the infrared hot air drying box were simulated and analyzed by CFD software,and the reasonable placement of the drying heating pipe was obtained.The simulation results were verified by experiments,and the following results were obtained:(1)The design of infrared hot air dryer was completed,and the infrared drying technology was applied to alfalfa drying.(2)Through single factor test and orthogonal test,the best fast drying combination is A3C2B2,that is,the temperature is 95?,the wind speed is 2.5m/s,the radiation distance is 150mm,and the best drying energy saving scheme is C3B2A2,that is,the wind speed is 3m/s,the radiation distance is 150mm,and the heating temperature is 95?.(3)CFD software is used to simulate the flow field and temperature field of the dryer,to explore the different arrangement of infrared heating tube and the coupling of wind speed,and to get the distribution of temperature field and flow field.