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Clarification of formative mechanism of uneven grain moisture in silo and the moisture distribution monitoring

筒仓粮食水分不均匀形成机理的阐明及水分分布监测

基本信息

批准号：
09660272
负责人：
KATO Koro
金额：
$ 2.18万
依托单位：
KYOTO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 2000
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09660272/
关键词：
moisture distribution grain layer dew condensation water movement TDR silo monitoring spectral image 水分移動マイクロ波 TDT 電磁波

项目摘要

The purpose of this study is to investigate the formative mechanism of uneven moisture distribution that cause mold and degradation of grain in storage silo and develop the monitoring system to detect abnormal moisture distribution. Unevenness of grain moisture forms during storage, even if a silo was charged with uniform moisture grain. We assumed the temperature difference between silo wall and grain causes the moisture movement. Firstly, we measured the temperature and humidity of the upper airspace and outside wall of a grain silo. Using the measured values and model experiment, we simulated the moisture movement in the grain silo. We reached the conclusion that main cause for the uneven moisture distribution is the dew condensation and the water droplet from wall or ceiling into the grain Iayer rather than the direct water movement between grain layers. Secondly, to monitor the irregularity of grain moisture distribution, inserting long metal bar etc.into the thick grain layer, time-domain spectroscopy TDR and TDT were experimented. As the reflected wave is generated in the boundary where the moisture differs, from the reflected wave form abnormality of the moisture distribution was detected. From the propagation delay time, the average moisture was detected at least to grain layer of about 2m. Thirdly, with non-contact measurement using horn antennas, same experiments of time-domain spectroscopy TDR and TDT were experimented. The average moisture was detected at least to grain layer of about 1m by TDT and anomalous reflection based on the moisture irregularity was detected to the depth of about 20cm from surface layer by TDR.Fourthly, on moisture distribution of surface grain layer, experiments which obtain the spectral image using the multiple wavelengths near 970nm of the water absorption band was carried out. As the result of the visualization processing, the moisture distribution image of the grain layer surface was obtained.

本研究的目的是探讨储粮仓内水分分布不均匀导致粮食霉变和变质的形成机理，并开发出检测水分分布异常的监测系统。谷物水分的不均匀是在储存过程中形成的，即使筒仓中装的是均匀水分的谷物。我们假设仓壁和粮层之间的温差是水分运动的原因。首先，测量了粮食筒仓上部空间和外墙的温度和湿度。利用实测值和模型试验，对粮仓内水分运动进行了模拟。得出水分分布不均匀的主要原因是露水凝结和水滴从墙面或天花板进入谷粒层，而不是谷粒层间的直接水分运动。其次，为了监测粮食水分分布的不规则性，在厚粮层中插入长金属棒等，进行了TDR和TDT的实验研究。由于反射波是在水分不同的边界上产生的，所以从反射波的形式可以检测到水分分布的异常。从传播延迟时间来看，平均含水率至少可以检测到2m左右的粒子层。第三，利用喇叭天线进行非接触测量，进行了TDR和TDT的相同实验。TDT至少探测到1m左右的颗粒层的平均水分，TDR探测到距地表约20 cm深度的基于水分不规则性的异常反射。4.关于表层的水分分布，进行了970 nm附近多个波长的光谱图像实验。作为可视化处理的结果，得到了颗粒层表面的水分分布图像。