دراسة رياضية وتجريبية لحركة المحصول داخل وحدة دراس محورية التدفق

Abstract

This study addresses the development of a mathematical model for analyzing the performance of a threshing unit with axial flow, focusing on the impact of feeding and the separation process at the threshing zone. The model examines the relationship between the crop's position within the unit, the separation rate, and the loss, taking into account the effects of design parameters (such as cylinder length and characteristics of the threshing drum apertures) and operational conditions (such as feeding rate and rotational speed).

The model was validated through experimental tests conducted on a tangential and axial flow threshing unit at the General Organization for Agricultural Scientific Research in the Syrian Arab Republic, using wheat crops under various feeding rates and moisture levels. The results showed a significant agreement between the model's values and the experimental data, with high correlation coefficients (0.94–0.96). The study revealed that threshing efficiency increased with higher feeding rates and rotational speeds, while efficiency decreased as crop moisture increased by (0.5–1.1)%. The model indicates that the maximum value for the unthreshed grain ratio occurs at (x=0.18 m), while the maximum value for the free grain ratio sf(x)s_f (x)sf​(x) is approximately 25% at (x=0.53 m). The highest separation rate reached 99.416% at a drum peripheral speed of 35 m/s, crop moisture of 25%, and a feeding rate of 3 kg/s.

The model provides an accurate tool for predicting the performance of threshing units, contributing to design optimization and loss reduction, with a relative error of (ep = 0.317%). The results are recommended for improving and designing threshing units based on optimal operational conditions, and future studies should be conducted to extend the model's application to other types of threshing units.