Evaluating the influence of double-channel inclined spreading blades on the effect of fertiliser granule spreading: DEM modelling and simulations

In view of the problems with the widely used single-channel linear fertiliser spreading blade, including obvious operational pulsation, a narrow fertiliser spreading width at low speeds, an irregular overlap of the fertiliser coverage area, and poor fertiliser distribution uniformity at high speeds, a double-channel inclined fertiliser spreading blade structure was designed in this research. Based on the discrete element method (DEM), the mechanism of fertiliser spreading by blades under different blade declination angles, blade inclination angles, disc rotation speeds and machine forward speeds was analysed, and the influences of each factor on the coefficient of variation Cv of fertiliser distribution and the effective width B of fertiliser spreading were analysed and summarised; the best blade fertiliser spreading performance was attained when the blade declination angle and inclination angle were 10° and 14° respectively, the disc rotation speed was 350 rev min⁻¹, and the machine forward speed was 1.3 m s⁻¹. At this moment, the coefficient of variation of the fertiliser distribution Cv was 15.17 %, and the effective width of the fertiliser spreading B was 9 m. In comparison with the initial foliar fertilisation, the Cv was decreased by 35.42 % and the B was increased by 28.57 %. It is shown that the discrete element method can effectively model the process of fertiliser spreading and predict the motion behaviour of fertiliser particles, and it is also shown that the use of this blade in fertiliser spreading machine can effectively improve the quality of fertiliser spreading operation.