芝麻和花生植物油料的渗透与流变特性测试及数值模拟.pdf

摘 要 当前植物油制取的主要方法为压榨法，但是有关榨油机的理论和实验研究 鲜有文献报道，研究成果较少，致使榨油机的发展相当缓慢。油料压榨理论的 研究具有重大的意义和应用价值。本文在现有油料压榨理论和试验研究结果的 基础上做了如下工作： （1）研究芝麻与花生的渗透物理特性。完成芝麻与花生渗透率试验，根据 流固耦合理论，建立可变形芝麻和花生饼的一维渗流微分方程并求解一维定常 耦合渗流问题的解析解。根据渗透率试验数据，采用Hopfield 神经网络优化算 法对芝麻和花生渗透率模型参数进行识别。研究表明：饼中孔隙压力与渗透率 均为非线性分布；渗透率与有效应力呈指数关系。 （2）研究芝麻与花生的蠕变特性。完成芝麻与花生的蠕变试验，采用模型 理论与经验模型相结合的方法建立了芝麻和花生非线性粘弹塑本构模型，并对 模型参数进行了识别。数值模拟了芝麻、花生、碎花生的蠕变，数值模拟的最 大相对误差分别为 5.7%、1.5%和 4.3%，结果表明，非线性粘弹塑性模型能较好 描述芝麻、花生流变特性。运用蠕变速率曲线确定了芝麻、花生、碎花生的平 衡压榨时间。 （3）研究芝麻与花生在压榨过程中的流固耦合渗流问题。考虑植物油料的 可变形和流变特性，植物油料的压榨过程是一个渗流场和流变场耦合渗流问题。 基于流固耦合渗流理论建立植物油料压榨过程的模拟模型，采用有限差分法和 有限元法交替求解渗流场和流变场。数值模拟了芝麻和花生压榨过程中的位移、 孔隙流体压力分布与消散。 关键词：芝麻，花生，压榨，渗透，流变 II ABSTRACT Mechanical pressing is one of the most popular methods of oil extraction from vegetable oilseeds at present. However, there is an extremely lack of the research of theories and experiments related mechanical pressing. Oil press develops quite slowly due to lack of achievements in theoretical research. The researches of theories of extruded vegetable oilseeds have momentous academic significance and higher applied value. Efforts have been made on the bases of available achievements of pressing theory and experiment research in this paper, which were as follows: (1) The permeated physical characteristics of sesame and peanut were studied. The permeation experiments of sesame and peanut were carried out. One-dimensional partial differential equation for fluids in porous media of oilseed cake was developed on the basis of theory of liquid-solid interaction, and analytic solution to problem of liquid-solid interaction of one-dimensional stead flow in porous media was proposed. The parameter inverse