| Wheat-corn two crops a year is the main planting patterns in Huanghuai region in China. Blockage, exposed seeds, sowing depth inconsistencies and other issues are major problems which affect the quality of sowing seriously exist in two-crops-a-year areas in North China. The active anti-blocking mechanism has great consumption and soil disturbance, while the passivity anti-blocking mechanism shows poor efficiency and adaptability. A new idea of pushing and separating straw was proposed based on the research of principle between wheat straw and anti-blocking mechanism. An innovative design was developed that was a driven rotary drum and passive residue separating device anti-blocking mechanism to prevent clogging with low consumption, high efficient and high adaptability. The main conclusions and results from the study are as follows:(1) On the basis of principle between wheat straw and anti-blocking mechanism, a new idea of pushing and separating straw was proposed. Cutting straw was replaced by pushing them to reduce power consumption while preventing clogging. An innovative design was developed that was a driven rotary drum and passive residue separating device anti-blocking mechanism. The drum pushed straw continuously and removed them out of seed bed when the planter sowing. The residue separating device prevented straw dropping on the seed bed to guarantee planting quality.(2)The interaction between wheat straw and anti-blocking mechanism and the separation characteristics of them were researched based on boundary layer theory and circulation flow around. The following conclusions can be drawn that streamline body has small shape resistance, and separation point was latter, the program was determined that ground wheel drove rotary drum to push the straw and separating device separated the straw threw by the drum. Preliminary results showed that the driven rotary drum and passive residue separating device anti-blocking mechanism can remove straw and create clean seed bed efficiently.(3)Models were established which have different parameters of ratio, number of bars and diameter by SolidWorks configuration features. The kinematics simulation in Adams showed that ratio, number of bars and diameter are directly proportional to the effect extent of poking straw. The results of further analysis indicated that the optimum parameters of the drum will be:transmission ratio of1.24, maximum diameter of150mm and number of bars of5for the rotary drum. Field trial results were found to be in an agreement with the simulation results and that no-till planter with rotary drums can accord the relevant standards about sowing.(4) The functions of separating device were separating the straw threw by the rotary drum in front of it, avoiding the straw falling into the seed bed, and leading straw placing on adjacent planter rows. Fluent simulation showed that convex shape was the most suitable appearance of separating device than others. Some parameters affected the separating results, such as opening angle, inlet velocity, and radius of curvature. Research on x-velocity component and distribution of wall shear stress were conducted when separating device was working with different parameters. The results showed that the optimum parameters of the separating device will be:opening angle of35°and curvature radius of750mm. (5) Field tests were conducted in Henan province, Hebei province and Shandong province for the planter with driven rotary drum and passive residue separating device anti-blocking mechanism. Field experiments demonstrated that the anti-blocking mechanism had good pass ability and high efficiency. The rate of soil disturbance and the rate of cleaning on seed bed were17.8%and81.1%respectively. The rate of exposed seed, the percent of pass in seed depth, fertilization depth and the spacing between seed and fertilization were1.1%,95%,91.7%,93.3%respectively. Various performance indicators had met the state standards and agronomic requirements. |
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