Design And Study Of Air Curtain Residual Film Blocking Device For Cotton Picker Of Picking Head

Cotton is an important bulk product second only to grain in China's agricultural planting industry,and Xinjiang cotton mainly uses a sub-membrane drip irrigation planting mode,which makes it easy for cotton to mix into a certain amount of residual film during mechanical harvesting,which seriously affects cotton quality.At present,the method of reducing the residual film content of mechanically harvested seed cotton is mainly to remove it after picking.However,during the seed cotton residual film removal stage,due to the multiple transfers and compaction of the seed cotton,the residual film removal must be opened multiple times,and the power consumption is large.In addition,multiple mechanical processing causes the residual film to become smaller,and it is more difficult to remove it later.For this reason,this paper proposes a method for preventing and controlling the membrane during the cotton harvesting process to reduce the residual film content of the seed cotton from the source.Aiming at the problem of residual film mixed into seed cotton,the way of residual film mixed into seed cotton during cotton mechanical harvesting was studied,and it was found that the negative pressure transportation of cotton caused the residual film fragments floating on the ground surface to leak at the bottom hole of the picking head and suck into the picking head,Mixed into the seed cotton,therefore,an air curtain method of blocking the residual film was proposed.An air curtain type residual film barrier device was designed,and the flow field inside the device was simulated and analyzed.At the same time,the wind speed of the nozzle of the barrier device was tested,the simulation results were verified,and the residual film barrier performance test experiment of the air curtain type residual film barrier device was performed.The main research work is as follows:(1)Through the investigation and experimental tests,the mixing path of the residual film of the mechanized seed cotton was determined,and a solution for blocking the residual film by a jet was proposed.Simulation analysis was performed.It was determined that when the jet opening width is greater than 4 mm and the initial velocity is greater than 5 m / s,the jet can block the longitudinal airflow at the leak hole,making the airflow velocity at the bottom of the picking head lower than the levitation speed of the residual film.(2)The air curtain type residual film barrier device was designed and processed,and the internal flow field of the air curtain type residual film barrier device was numerically analyzed using CFD technology.It was found that when the nozzle opening of the residual film barrier device was 4 mm,nozzle 1 was opened.The average wind speed of the nozzle is 6.1 m / s,the average wind speed of the nozzle 2 opening is 5.7 m / s,the average wind speed of the nozzle 3 opening is 4.3 m / s,and the uniformity of the wind speed of the three nozzle openings is good,which is consistent with the air curtain type Design requirements for membrane barriers.(3)The wind speed at the nozzle opening of the residual film barrier was tested to verify the reliability of the simulation analysis results.At the same time,two performance testing tests of the residual film barrier device were conducted.The first test was performed in the cotton field after the cotton was picked,and the barrier rate reached 85%.The second test was performed in the cotton field without the picked cotton.The results showed that the residual film was blocked.The rate reached over 80%.