Authors

Abstract

To address the uneven drying issue caused by temperature gradients during the cross-flow drying of paddy, this study designs a grain-turning device that periodically rotates clockwise, based on the cross-flow ventilation drying process of paddy. The device is intended to promote sufficient mixing of paddy grains in the drying section, thereby enhancing the drying uniformity and processing quality of paddy.Based on the thermo-hydro-mechanical (THM) coupling theory, computational fluid dynamics (CFD), and discrete element method (DEM) for particles, two mathematical analytical models of the cross-flow drying section (with and without the grain-turning device) were established. Using the EDEM-Fluent software coupling method, numerical simulations were conducted to investigate the variation patterns of temperature and moisture content of paddy grains in the two drying sections.The results indicate that the drying section equipped with the grain-turning device can effectively resolve the uneven distribution of moisture content and temperature in the grain layer caused by the air supply direction, verifying the feasibility of the device. To further verify its performance, a comparative experiment was carried out under the same parameters (drying duration: 100 min): before the improvement, the average moisture content of paddy in each layer was 15.24%, with a standard deviation of 1.26 and a variance of 1.59; after the improvement, the average moisture content decreased to 14.61%, with a standard deviation of 0.192 and a variance of 0.037. One-way analysis of variance (ANOVA) shows that the inter-group F-statistic reaches 41.536, which is much higher than the critical value (4.41) corresponding to the significance level of 0.05, with p < 0.001.In conclusion, the drying uniformity of paddy with the grain-turning device is significantly superior to that of conventional drying, providing a practical technical reference for the optimization of paddy drying production processes.

Abstract in Chinese

针对稻谷横流干燥过程中因温度梯度引发的干燥不均匀问题，本文基于稻谷横流通风干燥工艺，设计一种可周期性顺时针运动的谷物翻粮装置，以促进干燥段内稻谷颗粒充分混合，进而提升稻谷干燥均匀性与加工品质。基于热流固耦合理论（THM）、计算流体动力学（CFD）与颗粒离散元法（DEM），建立了包含有无翻粮装置的两种横流干燥段数学解析模型，采用EDEM-Fluent软件耦合方法，对两种干燥段内稻谷颗粒的温度及含水率变化规律进行数值模拟。结果表明：配备翻粮装置的干燥段可有效解决因送风风向导致的粮层含水率与温度分布不均问题，验证了该装置的可行性。为进一步验证效能，在相同参数下（干燥时长 100 min）开展对比试验：改进前各层稻谷含水率均值 15.24%、标准差 1.26、方差 1.59；改进后均值降至 14.61%、标准差 0.192、方差 0.037。单因素方差分析显示，组间 F 统计量达 41.536，远高于显著性水平 0.05 对应的临界值（4.41），且 p<0.001。综上，配备翻粮装置的稻谷干燥均匀性显著优于常规干燥，为稻谷干燥生产工艺的优化提供了切实可行的技术参考。