Tao Cui

Simulation Analysis on Air Current Field of Positive-pressure for Metering Device of Maize Precision Planter

Abstract. Based on the principle of aerodynamic seed-filling and pressure differential seed-taking, the positive-pressure maize precision metering device was designed and tested. In order to optimize the mechanical structure parameters and the movement of air flow in the positive-pressure maize precision metering device, simulation research was carried out with orthogonal method and FLUENT tools. Three factors; the quantity of holes, the angle of air inlet and the position of air inlet were selected to study their influences on air current and seeding quality. Simulation analysis based on the turbulence model of RNG k-Iµ and the numerical predictions of SIMPLE method was done. In addition, the research results were also validated by the experiment. Its performance such as working air pressure, seed overlap index, missing index and seed allocation eligible rates were investigated under laboratory conditions, Through the comparisons of optimal parameters between the simulation and the experiment, the validity of the simulation results were confirmed. The research revealed that the area of slot hole on the metering device disc and the angle of air inlet on the coat of metering device is the pivotal factor.

Experimental Study on the Impacts of Operating Parameters to the Performance of Air-blowing Seed-metering Device

Performance of the air-blowing seed-metering device is mainly decided by its two operating parameters—forward speed and air pressure. The influences of the two operating parameters on seeding quality were investigated in laboratory, using two factors repeated completely random test design. Graphical processing and two-factor repeated analysis of variance (ANOVA) were done based on the experiment data. It is observed that both the two factors and their interaction affected the QFI (quality of feed index), MULT (multiple index) and MISS (miss index) significantly. Lower forward speeds need lower air pressure to avoid blowing away all the seeds to cause miss-seeding. Higher forward speeds need higher air pressure to blow away the surplus seeds in limited time. The CV (coefficient of variation) values were acceptable for precision seeding in all trails. The appropriate range of air pressure fitted to different forward speed was provided according to the experiment data and analysis.