Structural Design And Theoretical Study Of Sawdust Drum Dryer

In order to improve the current situation of the scarcity of timber resources in our country,we develop the wood chip processing technology in which the thinning wood is processed into culture materials for fungus.For this purpose,we design a sawdust drum dryer,which is specially used for the evaporation of wood chips processed by thinning wood.It has the characteristics of high efficiency,small footprint and easy to use.After analyzing the structure and principle of the existing conventional drum dryer at home and abroad,combining with the demand for wood chip processed from thinning wood,we finally decide to use electric heating as the drying heat source and airflow feeding,then plan the layout of the whole wood chip dryer.We make the kinematics analysis of the drum and its materials by using the method of theoretical analysis,so we obtain the range of the rotational speed required for the normal operation of the drum by calculation.We design the structure of the whole machine and each functional component,and according to the results of the motion analysis,combining with the analysis of the resistance of the drum,obtain the resistance torque of the drum dryer,and then we select the motor and the speed reducer and distribute the transmission ratio.By using finite element analysis software,we make the finite element analysis(static analysis and modal analysis)of the drum and roller support,and get the stress,strain,maximum deformation and other parameter maps,so we verify the strength and stiffness meet the design requirements.Through the experiment,we derive the equation of the water diffusion coefficient of slender wood chips,and obtain the quadratic regression equation of the water diffusion coefficient of slender wood chips under different water temperatures.We get the conclusion that heat loss of the drum dryer is mainly owing to the convective heat transfer between the outer wall of the drum and the external environment.Using the fluid mechanics analysis module in the finite element software,we make the hydrodynamic analysis of the inside of the drum under two states,and get the fluid velocity trace diagram,pressure distribution cloud map and temperature distribution map,then analysis and judge the calculation results to verify the designed copy plate and fin heating tube are rational in fluid dynamics.