机械通风降温效果的数值评估

NUMERICAL EVALUATION ON THE COOLING EFFECT IN MECHANICAL AERATION FOR GRAIN STORAGE

地槽通风是机械通风的常用形式,是保证粮食安全储存和保持粮食品质的重要措施。常规的试验研究测量方法难以全面和准确评估设计的有效性和合理性。本研究利用计算机流动模拟的方法(CFD)对常用的U形地槽通风方案进行了数值研究,获得了风道中流速和压力分布的关键性数据,发现了与实际现象相符合的通风死角区域,同时又发现了常规测量手段中难以探测到的风道之间存在的通风薄弱区域,在理论上分析了存在通风死角和风道压力损失的原因。计算流体力学研究方法的运用可成为机械通风优化设计研究的有效工具,为今后机械通风应用技术的发展提供针对性和实用性的依据。

Duct ventilation is a widely--applied method in mechanical aeration, It is an importent measure to secure the grain quality safety in gran storage. Conventional test methods are difficult to comprehensively and accurately evaluate the effectiveness and rationality of the duct designs. In this study, computational fluid dynamics（CFD） is applied to simulate the U--shaped duct aeration. Important data such as flow velocity and pressure distribution are acquired ; the dead areas are detected, which accords with actual measurements well. Less--effective area between ducts is a new finding, which is hard to be detected through test methods. The causes of aeration dead--area in the grain bulk and pressure loss along the ducts are analyzed theoretically. The application of CFD technology will be an efficient tool to develop mechanical aeration technology in grain storage. This methodology provides targeting and practical references to the optimization design in this field.