Mathematical Modelling and Optimization of the Distribution Uniformity of Twin-Disc Centrifugal Spreader

The objective of this study was to obtain the mathematical models and to optimize the distribution uniformity in the twin-disc granular broadcast spreader. This study aims to optimize the variables considered in the study to minimize the coefficient of variation (CV, %) for three different fertilizers. A domestic twin-disc granular broadcast spreader was used along with three different granular fertilizers, namely urea, compound fertilizer of 15-1515, and compound fertilizer of 2020-0. The variables considered in the study were the height of vanes (H), vane angle (a), fertilizer flow rate (Q), and disc peripheral speed (V). Not only the main effects on the distribution uniformity of each of these variables but also interactions of these variables are the subject matter of this study. Therefore, the models formed in polynomial form, including the interactions of variables, were used to express the performance of distribution uniformity in mathematical form. To achieve the objectives, Response Surface Methodology (RSM) was used. The study builds on RSM, which helped to develop mathematical functions in the form of polynomial models, thus making it possible to find the optimum level of the variables from these models, and finally, to verify the optimums. According to the results of the verification tests, the twin- disc granular broadcast spreader provided "good" range of distribution uniformity, which was 6.775% for urea fertilizer, 8.135% for compound fertilizer of 15-15-15, and 8.11% for compound fertilizer of 20-20- 0, while CV of distribution from the original spreader was 19.29%.