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Previous studies on sugarcane harvester extractors have mainly focused on improving harvest quality and reducing the impurity rate and loss rate, which often ignored the issue of high energy consumption. To reduce the energy consumption of the extractor while maintaining the original impurity rate and loss rate stable, firstly, a blade element analysis method with aerodynamic theory was put forward to analyze the stress of the extractor blade, and the energy consumption equation and influencing factors of extraction were obtained. Subsequently, the computational fluid dynamics model of the exhaust extractor was established. Computational fluid dynamics (CFD) and the SST k-ω model were used to analyze the mechanism of various influencing factors on the energy consumption and internal flow characteristics of the extractor. The changes in various parameters were analyzed and discussed with respect to the resulting variations in internal pressure, velocity, vortex structure, and lift–drag coefficient of the extractor. A test bench of the extractor was built, and orthogonal tests were carried out with energy consumption, impurity rate, and loss rate as test indicators. Considering the results of the simulation and bench test comprehensively, the combination of a rotational speed of 1450 RPM, a blade number of 3, an installation angle of 25°, and a blade chord length of 200 mm was optimal for the extractor. Finally, a comparative test was carried out between the optimized extractor and the original extractor. The results demonstrated that the energy consumption of the optimized extractor was reduced by 15.49%. The impurity rate decreased by 3.51%, and the loss rate decreased by 12.39% compared to the original extractor. The study can provide a theoretical and experimental basis for designing and optimizing extractor performance. [ABSTRACT FROM AUTHOR]

Sugarcane harvester extractors are used to separate impurities during mechanical harvesting and their performance directly determines the impurity content of sugarcane billets. In this study, computational fluid mechanics (CFD) was used to analyse the flow field near the impeller of original design of extractor. The SST k-ω model and realisable k-ε model were used to calculate the turbulence in 2D and 3D flow fields respectively. The simulation results of 2D models showed that sharply shape from the leading to trailing edges of the original blade design could cause more energy losses. An improved blade design with smoother leading edge and trailing edges had improved performance with a maximum lift coefficient increased by 28.7%. 3D simulation results showed that when the fan speed was 1050 rpm, 1350 rpm and 1650 rpm respectively, the total pressure efficiency of the improved extractor was 11.45%, 9.03% and 6.7% higher than the original extractor, respectively. Impurity content experiments showed that when the feed rate was 1 kg s−1, 2 kg s−1 and 3 kg s−1, compared with the original extractor, the impurity content of the improved extractor decreased by 0.46, 0.41 and 0.71 percentage points at most. The results showed that the impurity content and energy consumption of the improved extractor was less than that of the original design of extractor. • Study proposes improvement method of extractor blade using CFD. • Improvements suggested by CFD models verified by experiment. • Blade modified by simple changes improved aerodynamic performance of extractor. • Modified blade enhanced cleaning performance and energy utilisation. [ABSTRACT FROM AUTHOR]