Three dimensional models of porosity and airflow resistance in stored grain bulks

储粮散装孔隙度和气流阻力的三维模型

• 批准号: RGPIN-2022-03663
• 负责人: Jian, Fuji
• 金额: $ 2.33万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=746302
• 关键词: Three; dimensional; models; porosity; airflow

The grain aeration and drying process is always at risk of failure because of its weather dependency. The presence of dockage, fines, and foreign materials (DFF) in stored grain exacerbates this issue further because the DFF in stored grain can plug the air space among grain kernels, causing uneven airflow resistance. The nonuniform airflow results in overdried grain at high airflow locations and wet (spoiled) grain at low airflow locations inside the same bin. The two major factors influencing the airflow resistance distribution are the pore structure among grain kernels (size, shape, connectivity, tortuosity of the pores, and orientation of the pore to the airflow direction) and properties of fluids (air velocity and viscosity). The pore structure is directly influenced by grain types (kernel size and shape) of the stored grain and amount and size of DFF. Porosity is strongly related to pore structure and airflow resistance in a bin. No model of airflow resistance considering the distribution of DFF (both in size and percentage) inside grain bulks has yet been developed, leading to a knowledge gap in this area. The long-term goal of my research program is to mathematically model the physical and biological behaviours of stored grain ecosystems. In the next 5 years, I will focus on objectives to fill this gap by developing 3D finite element airflow resistance models inside stored grain bulks and considering the effect of DFF (both size and percentage) on porosity and airflow resistance. To develop and validate these models, I propose to quantify the relationship among porosity, DFF size distribution, airflow direction, airflow velocity, and airflow resistance. The proposed experiments will use novel technique to characterize pore structures and measure air flow resistance distribution. The results from this research will not only contribute to the fundamental knowledge of pore structure and flow through grain bulks, but also provide a rational analysis tool for the design and operation of bulk solid storage systems. The developed airflow resistance distribution models will help design engineers to lay out the aeration system optimally and grain owners to conduct a optimal grain drying and aeration, so quality and quantity losses can be avoid and Canada's international reputation as a reputable, reliable, and consistent producer of high-quality grain can be maintained. Two MSc, 1 PhD, and 3 undergraduate students will be trained through this proposed program. An individualized training plan and approach will be developed. Through this rigorous training under an EDI (equity, diversity, and inclusion) environment, all students will be trained on the advanced management of stored grain and be prepared to become independent for their future careers. They will also advance their technical skills in areas important to grain storage management.

由于对天气的依赖，粮食通风干燥过程总是有失败的危险。储粮中的淤渣、细粒和异物（DFF）的存在进一步加剧了这一问题，因为储粮中的DFF会堵塞谷粒之间的空气空间，导致气流阻力不均匀。气流不均匀导致同一仓内高气流位置的谷物过干，低气流位置的谷物湿（变质）。影响气流阻力分布的两个主要因素是籽粒间的孔隙结构（孔隙的大小、形状、连通性、弯曲度以及孔隙对气流方向的取向）和流体的性质（气流速度和粘度）。储粒的粒型（粒大小和粒形）、DFF的数量和大小直接影响孔隙结构。孔隙率与仓内的孔隙结构和气流阻力密切相关。目前还没有考虑颗粒内部DFF分布（包括尺寸和百分比）的气流阻力模型，导致这一领域的知识空白。我的研究项目的长期目标是用数学方法模拟储藏粮食生态系统的物理和生物行为。在接下来的5年里，我将专注于填补这一空白，通过开发存储谷物块体内部的三维有限元气流阻力模型，并考虑DFF（尺寸和百分比）对孔隙率和气流阻力的影响。为了开发和验证这些模型，我建议量化孔隙度、DFF尺寸分布、气流方向、气流速度和气流阻力之间的关系。所提出的实验将采用新颖的技术来表征孔隙结构和测量气流阻力分布。该研究结果不仅有助于了解颗粒体孔隙结构和流动的基础知识，而且为颗粒体储存系统的设计和运行提供了合理的分析工具。开发的气流阻力分布模型将帮助设计工程师优化通风系统布局，帮助粮主进行最佳的谷物干燥和通风，从而避免质量和数量上的损失，保持加拿大作为信誉良好、可靠的高品质粮食生产国的国际声誉。该项目将培养2名硕士、1名博士和3名本科生。将制定个性化的培训计划和方法。通过EDI（公平、多元化和包容）环境下的严格培训，所有学生都将接受先进的仓储管理培训，并为未来的职业生涯做好独立准备。他们还将提高他们在粮食储存管理重要领域的技术技能。