Design And Experiment Of The Key Gathering Component Of The Self-propelled Red Jujube Strip Gathering And Picking Device

With the biggest yield and planting area of jujube,Xinjiang is an important jujube production area in China.The good natural condition for jujube planting in southern Xinjiang makes produced jujube there tastes great.Before picking up,red jujube strips needs to be gathered using knapsack fire-fighting fan.However,this method is labor-intensive,dusty and low efficiency.With an aim to solve the problems in red jujube strip gathering,this thesis designed and trial-produced the key gathering component of self-propelled red jujube strip gathering and picking device.This thesis established air-blowing test bench for ground jujube to explore the influence law of main work parameters and key component parameters on strip gathering rate.The optimum parameter combination was found by orthogonal test at appropriate level.By using Fluent,this thesis carried out a fluid simulation on nozzle to find out the best structure of the nozzle.Then basing on the research and results of air-blowing test bench experiment on ground jujube,this thesis trial-produce the key component of this device.The details are as following:(1)This thesis studied on red jujube planting pattern and material characteristics.The study found that the red jujube planting pattern was related to shapes of trees.The trees were mostly stem-and open center-shaped,and the line spacing×row spacing in the jujube gardens were 2m×1m and 4m×1m respectively.Then this study measured the material characteristic parameters of gray jujube,including its triaxial dimensions,weight,volume,density,suspension velocity and rolling friction coefficient.The results were that the hardness of gray jujube was 5.28kg/cm~3～12.82kg/cm~3,rolling friction coefficient0.15～0.25,and suspension velocity 19.25m/s～22.57m/s.(2)This thesis explored the influence law and significance of various factors on the strip gathering rate through a ground jujube air-blowing test bench.Taking the strip gathering rate as the indicator,the test bench carried single-factor tests on the forward speed,the exit wind speed,the nozzle rotation angle and the nozzle height from the ground.The orthogonal test was carried out on the level selected from the single-factor test results to determine the optimal combination of the strip gathering operation parameters.The results of single-factor tests showed that the strip gathering rate was negatively correlated with the forward speed and the nozzle rotation angle,but positively correlated with the exit wind speed,and showed a fluctuating relationship with the height from the nozzle to the ground.L9(3~4)orthogonal test was carried out on the level of factors selected from the single-factor test results.The results showed that the order of the influence of each factor on the strip gathering rate of ground jujube was the exit wind speed>nozzle rotation angle>forward speed>height of nozzle from ground.The optimal combination of operating parameters obtained from the test is the exit wind speed 80m/s,forward speed 1.5km/h,and the nozzle rotation angle 15°,height of nozzle from the ground 15 cm,and the gathering rate of this combination was98.84%.(3)This thesis used the Fluent simulation software to analyze the nozzle flow field and improve the nozzle structure.This thesis built the physical models of the tapered,equal-width and tapered duck tips for fluid simulation,and used the cylindrical type(without the nozzle)for control test.The results showed that the duck-tipped nozzle can effectively increase the airflow velocity,and the tapered duck-tip has the best effect.Orthogonal test was designed for the structure parameters of the tapered duck tips.The test results showed that the optimal scheme of the nozzle structure was:the outlet length 50mm,the outlet width20mm and the nozzle length 100mm.In this combination,the axial airflow velocity at 2m was 44.17m/s,and the airflow width at 2m was 0.90m.(4)Combined with the planting pattern and material characteristics of red jujube,the tes results of ground jujube air-blowing test bench and the selection of improved nozzle structure,this thesis found out the working principle design scheme and the main parameters of the key gathering component of the self-propelled red jujube strip gathering and picking device.Also,theoretical analysis and design were carried out on the jujube blocking mechanism,copying reciprocating mechanism,auxiliary collecting mechanism,fan model and hydraulic system.Its operation mode is single-side gathering device.The overall size of this device was 2m,1.5 and 0.4m,and the fan model was 9-19-4A.The key gathering component of the self-propelled red jujube gathering and picking device were trial-produced and tested.The test results showed that the sample device met the design requirements.