Numerical Simulation And Experimental Study On The Pneumatic Collecting System Of Camellia Oleifera Fruits

Camellia oleifera fruits have high edible and industrial value,camellia oleifera industry belongs to the innovative forestry economy,has a very broad development prospect.At present,the harvest of camellia oleifera fruits mainly depends on manpower.The defect of manpower has seriously restricted the development of camellia oleifera industry.In view of the difficult situation of oil tea industry,the pneumatic collecting system of oil tea fruit was studied and explored.Taking camellia oleifera fruits as the object,this paper combines the gas-solid coupling theory,discrete element method(DEM)and computational fluid dynamics(CFD)coupling numerical simulation method(CFD-DEM)to realize the pneumatic conveying problem of camellia oleifera fruits,and studies the following three aspects in the pneumatic conveying system of camellia oleifera fruits.In simplified description camellia fruit appearance characteristics,on the basis of coupling based on gas-solid two-phase flow theory and the theory of Hertz contact of camellia fruit in axial flow field and particle dynamic characteristics of vortex field and the collision between particles and wall were analyzed,and the clear of the fruit of the stress for pneumatic conveying system,deduce the kinematics equation by the collision of particles and the wall.Through the classification of the traditional pneumatic conveying system,the conveying state and conveying mode of camellia oleifera fruits in the pneumatic conveying system were clarified,and the theoretical research results provided theoretical basis for the numerical simulation of camellia oleifera fruits in the pneumatic conveying system.Based on the CFD-DEM coupling numerical simulation method,the negative pressure pneumatic conveying behavior of camellia olerata was numerically simulated when the vertical pipe tilting Angle and the air conveying velocity of the system were different.By changing the diameter of the conveying pipe,it is shown that with the increase of the conveying pipe diameter,the pressure loss of the system decreases,the turbulence kinetic energy of the system continues to increase,the kinetic energy of the oil tea fruit in each stage of the pipeline remains basically the same,and the mass flow rate of the oil tea fruit in the system increases.According to gas phase flow characteristics and oil tea fruit transport characteristics,it is considered that the system can transport oil tea fruit best when the pipe diameter of the pipeline is 90mm.When pipeline diameter is 90 mm,by changing the intermediate pipe Angle research shows that:with the increase of the intermediate pipe Angle,the system pressure drop increase after the first decreases,and remains the same,after adding system of turbulence kinetic energy decreases first increases,then remain constant,camellia fruit kinetic energy continue to increase in the pipe gas-solid coupled together basic remains the same,and the system transport fruit of the mass flow rate increases after the first decreases,and then remain unchanged.According to the characteristics of gas-phase flow and oil tea fruit transportation,it is considered that the system has the best performance for oil tea fruit transportation when the inclination Angle of the intermediate pipeline is 15°.When pipeline diameter is 90 mm,the middle of the pipe when the Angle is 15°,by changing the system conveying gas velocity studies have suggested that the system pressure loss of the gas phase and the turbulent kinetic energy with the increase of gas velocity and current increase,camellia fruit kinetic energy in the pipeline and gas solid bonding force increased with the increase of the conveying gas velocity,mass flow rate with the increase of the gas velocity decreases after increasing first,finally remained stable.According to the characteristics of gas phase flow and oil tea fruit transportation,it is considered that the performance of oil tea fruit transportation is optimal when the system air supply parameter is 35m/s.Finally,the optimal structural parameters and conveying parameters of the system were obtained:when the conveying pipe diameter was 90mm,the inclination Angle of the intermediate pipe was 15°,and the conveying gas velocity was 35m/s,the system mass flow rate was the best,and the optimal value was 1.09kg/s.According to the numerical simulation study,the pneumatic conveying test bed of camellia oleiensis was built,the signal acquisition system was constructed,and the experimental research on pneumatic conveying of camellia oleiensis was carried out.The results show that there is a 9.7%error between the experimental data and the simulation data,which indicates that the numerical calculation model is in good agreement with the actual test bed,and the numerical calculation model is correct and effective.