Agricultural centrifugal fans play a pivotal role in agricultural machinery, particularly in the context of combine harvesters. The performance of these fans significantly impacts the overall operational efficiency of the machine. Given the absence of robust performance testing and evaluation methodologies for agricultural centrifugal fans, this study assesses fan performance by examining the actual air–flow dynamics in a certain space at its outlet. Subsequently, the effects of various structural parameters on airflow smoothness and attenuation are investigated by computational fluid dynamics simulation analysis. The optimal detection air duct is developed, and the measured fan performance parameters and evaluation indexes are discussed and analysed using bench tests. The obtained results indicate that the arc connection section exhibits reduced interference with the air outlet of the agricultural centrifugal fan. Additionally, the attenuation section, characterised by a diffusion angle of 4°, effectively captures air attenuation properties. Minimal wind speed fluctuation is observed at the measuring point equidistant from the inlet and outlet of the steady flow section. Consequently, optimised structural parameters for the detection air duct and the specified location of the measuring point are determined. Furthermore, the performance parameters of the agricultural centrifugal fan are measured, and dimensional and dimensionless performance evaluation curves are generated based on bench testing. The fan's efficiency increases with higher air volume and flow coefficient but tends to change gradually due to the rate of increase, aligning with the expected performance of the agricultural centrifugal fan. The proposed performance detection device and evaluation method for agricultural cleaning can accurately detect the operational performance of the agricultural centrifugal fan.

中文翻译：

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农用清扫离心风机检测风道性能及评价指标研究

农业离心风机在农业机械中发挥着关键作用，特别是在联合收割机中。这些风扇的性能显着影响机器的整体运行效率。鉴于农用离心风机缺乏可靠的性能测试和评估方法，本研究通过检查其出口处特定空间的实际气流动力学来评估风机性能。随后，通过计算流体动力学仿真分析研究了各种结构参数对气流平滑度和衰减的影响。研制了最佳检测风道，并通过台架试验对实测风机性能参数和评价指标进行了讨论和分析。结果表明，弧形连接段对农用离心风机出风口的干扰较小。此外，衰减部分的扩散角为4°，可有效捕捉空气衰减特性。在距稳流段入口和出口等距的测量点处观察到最小的风速波动。由此确定了检测风道的优化结构参数和测点的具体位置。此外，还测量了农用离心风机的性能参数，并根据台架试验生成了有因次和无因次性能评价曲线。风机的效率随着风量和流量系数的增加而增加，但由于增加的速度而趋于逐渐变化，这与农用离心风机的预期性能一致。所提出的农用清洁性能检测装置及评价方法能够准确检测农用离心风机的运行性能。