CAJ | 학술논문

为了解小麦平床通风干燥特性,该文以某型号箱式通风干燥机为试验设备,开展小麦收获后干燥试验研究,测试分析了干燥床风场分布、干燥床层含水率分布、温度分布及耗能等特性.研究表明,该设备在水平面和垂直面均存在较明显的干燥速度差异;在干燥6 h 结束时整个小麦床层的最大含水率差异超过3%,影响整批物料的干燥效率和干燥成本;干燥5 h 后整批物料含水率达到小麦贮藏要求,每1 kg 物料含水率下降5%的能耗成本为0.09元.根据试验研究结果,提出在入风口增加导风栅格、干燥仓体4个角采用圆弧过渡处理、采用气流换向机构和交替换向通风干燥工艺等改进措施来改善该设备干燥均匀性.研究结果为该类型干燥机的小麦干燥工艺优化及设备改进设计提供了依据.
위료해소맥평상통풍간조특성,해문이모형호상식통풍간조궤위시험설비,개전소맥수획후간조시험연구,측시분석료간조상풍장분포、간조상층함수솔분포、온도분포급모능등특성.연구표명,해설비재수평면화수직면균존재교명현적간조속도차이;재간조6 h 결속시정개소맥상층적최대함수솔차이초과3%,영향정비물료적간조효솔화간조성본;간조5 h 후정비물료함수솔체도소맥저장요구,매1 kg 물료함수솔하강5%적능모성본위0.09원.근거시험연구결과,제출재입풍구증가도풍책격、간조창체4개각채용원호과도처리、채용기류환향궤구화교체환향통풍간조공예등개진조시래개선해설비간조균균성.연구결과위해류형간조궤적소맥간조공예우화급설비개진설계제공료의거.
In recent years, the current sun-drying facilities in Chinese rural area are far from being able to meet the requirements of post-harvest drying of major grain crops because of the rapid development of harvesting mechanization, and grain dryers are widely demanded to reduce post-harvest losses of rural grain crops. As an economical and practical grain dryer, bin-ventilation dryer is considerably fitting for Chinese rural production practice. @@@@In order to understand the wheat ventilation drying characteristics in flat bed,experimental studies of post-harvest wheat drying were performed on SKS-480 type of bin-ventilation dryer, which involved in testing and analysis of the air field distribution upon the no-load aperture plate, the moisture distribution of materials, the temperature distribution of dry bed and the energy dissipation. The wheat dry bed was 15cm in depth, and the total drying time was set as 6 h, with air temperatures 50℃ during the first three hours and air temperature 60℃during the latter three hours. For testing temperature and moisture content of the wheat dry bed, the drying region area on horizontal plane was evenly divided into 25 unit areas, and the 15 cm-deep dry bed on vertical plane was evenly divided into upper, middle and bottom layers, respectively. @@@@It was concluded that there was evident drying speed difference among the horizontal plane and vertical plane of the dry bed, which was caused by the uneven wind field distribution and the dry bed depth. After 6 h of drying, there was very significant difference (p<0.01) among the materials temperatures of upper, middle and bottom layer of wheat bed. And average moisture content of bottom layer was significantly higher than that of upper and middle layers (p<0.01), while there was smaller difference (p>0.01) between the average moisture content of upper and middle layers. And the maximal difference of moisture content among the whole dry bed was more than 3%, which failed to meet the relevant industry standards and the national standards, affecting the drying efficiency and drying cost of the entire batch of materials. After 5 h of drying, average moisture content of the whole dry bed was 11.5% (w.b.) and achieved the requirements of wheat storage. The energy cost for removing 5% moisture content of 1 kg wheat on this dryer was ￥0.09, while that of large-scale wheat dryers was￥0.04. For wheat drying, this dryer had no advantage in terms of operation energy costs against the large-scale one. Consequently, there was a lot of room for the improvement of the drying performance on this kind of dryer. @@@@Based on the experimental results, some improvement measures of drying uniformity of this dryer were put forward, including setting wind-guide grids in the air inlet and rounding four corners of the drying bin to improve the uniformity of air field distribution in the material bed, and adopting airflow-reverse device and alternate-reverse ventilation drying process to reduce the difference of drying rate along the dry-bed depth. The study can provide a reference for the improvement of the similar dryers.