振动风选式稻谷清选机清粮装置流场分析与结构优化

Flow Field Analysis and Structural Optimization of Vibrating Air-selected Rice Grain Cleaning Device

摘要:

针对现有风选谷物清选机加工稻谷时,因稻谷表面毛刺相互粘附,使杂质被粘附在稻谷之间无法脱离,导致清选质量变差的问题,建立清粮剪切流场与稻谷粘附模型,确定稻谷在清粮流场中的粘附扰动规律。基于流场-稻谷耦合关系,确定稻谷粘附扰动与稻杂分层的临界速度范围,并结合连续方程优化清粮装置结构参数,得到参数优化范围为:清粮室高度760 ~ 840 mm、清粮室长度1 960 ~ 2 040 mm、清粮室后挡板长度540 ~ 620 mm。采用流固耦合仿真方法,进行三因素五水平二次正交旋转组合试验,确定最优结构参数组合。试验结果表明,当清粮室高度为800 mm、清粮室长度为2 000 mm、清粮室后挡板长度为580 mm时,含杂率为0.853%,损失率为1.11%,满足清选农艺要求。验证试验表明,在最优参数组合下,含杂率、损失率分别为0.88%、1.14%,与优化结果相对误差控制在3%以内,表明优化结果具有可靠性。该研究可为风选式稻谷清选装置的结构优化提供理论依据与技术参考。

Abstract:

Aiming at the problem that when the existing grain sorting machine processes rice, the impurities are mixed between the rice to form stubborn impurities due to the mutual adhesion caused by the burrs on the surface of the rice, which leads to the deterioration of the sorting quality, the model of the shear flow field and the adhesion of the rice was established to determine the adhesion disturbance law of the rice in the flow field of sorting environment. The model can accurately characterize the adhesion interaction between rough rice and impurities under shear airflow conditions. Based on the flow field-rice coupling relationship, the critical velocity range of rice adhesion disturbance and rice impurities stratification was determined. Combined with the continuous equation, the structural parameters of the grain sorting device were optimized, and the optimization range was obtained: height of the grain cleaning chamber was 760 ~ 840 mm, length of the grain cleaning chamber was 1 960 ~ 2 040 mm, and length of the rear baffle of the grain cleaning chamber was 540 ~ 620 mm. The parametric optimization tests were carried out by fluid-solid coupling simulation with a quadratic orthogonal rotary combination design. The optimal combination of structural parameters was determined by three-factor and five-level orthogonal test. The results showed that when the height of the grain cleaning room was 800 mm, the length of the grain cleaning room was 2 000 mm, and the length of the rear baffle of the grain cleaning room was 580 mm, the impurity rate was 0.853%, and the loss rate was 1.11%, which met the agronomic requirements of the sorting. The validation test showed that under the optimal parameter combination, the impurity rate and loss rate was 0.88% and 1.14%, respectively, and the relative error with the optimization result was within 3%, indicating the reliability and accuracy of the optimized results. The research result can provide theoretical basis and technical reference for the structural optimization of rice sorting device.