1、 天津工业大学工程硕士学位论文论文题目：规模化线发射静电纺丝过程中流体均匀分配系统的研究 工程领域： 纺织工程 学习方式： 全日制攻读 在职攻读 作者姓名： 学校导师： 企业导师： 完成日期： 学位论文的主要创新点一、基于流体动力学和粘弹性力学，首次从纺丝流体均匀分配的角度来改善静电纺丝技术。并且率先提出将非织造熔喷技术中的熔体分配系统运用到静电纺丝溶液的均匀分配上，将熔喷技术和静电纺丝技术有机地结合在一起。为实现静电纺丝技术的工业化开拓了新思路，为实现纳米纤维材料的规模化和产业化生产奠定了理论和实践基础。二、对非织造熔喷技术中的衣架模型进行了研究，建立三维立体衣架模型，采用有限元的方法模拟了
2、静电纺丝液在三维衣架模型内的流动情况，针对纺丝液的特性对衣架模型的几何参数做了调整，使得衣架模型能够对纺丝液起到均匀分配的作用。三、在熔喷衣架模型的基础之上，建立了衣架式多针静电纺丝头，模拟了静电纺丝溶液在其内部的流动情况，并对纺丝液在其内部的压力分布做了系统的、定量性的研究。同时分析了非牛顿指数、粘度、密度和流速等因素对纺丝液流动均匀性的影响，最终得出最佳参数组合。四、根据纺丝液在衣架式多针静电纺丝头中的流动规律，拟合出纺丝液流动的压力分布曲线方程，建立曲面衣架式多针静电纺丝头，并通过结合静电场的场强分布规律来验证方程和曲面衣架式多针静电纺丝头的合理性。摘 要近年来，随着制备纳米纤维的方法得
3、到了大量的研究与开发，纳米纤维材料在诸多领域中被广泛使用。而静电纺丝技术是制备纳米纤维的最有效的方法之一，其具有简单有效、原料适应性广和尺寸可控等优点。目前，在某些领域已经实现了纳米纤维的工业化生产和应用。在探索静电纺丝技术工业化的道路上，人们做了许多的努力，主要集中在改进纺丝头形式上、接收装置上和聚合物可纺性等方面，很少有人从输送纺丝液的角度上改进静电纺丝技术。而纺丝液的供给系统存在供液不连续、安全隐患等问题，亟待我们去解决。市场上能既能够达到工业化生产，又与静电纺丝技术具有相似性的技术是非织造熔喷技术。熔喷设备里最重要的模头部分可以在熔喷过程中连续均匀地喂液，不仅提高了生产效率，还保证了产
4、品的质量和生产的安全性。因此，我们借鉴熔喷设备里的模头技术，将其应用到静电纺丝液的供给和分配上来，提高静电纺丝技术中纺丝液的分配均匀性，为静电纺丝技术的工业化生产奠定基础。因为衣架模型是熔喷技术中使用最广的模头，因此被我们应用于静电纺丝过程中纺丝液均匀分配的研究当中。首先，采用 COMSOL 有限元软件对静电纺丝溶液在基础衣架模型中的流动情况做了系统性研究。为了提高衣架模型对纺丝液分配的均匀性，对构建衣架模型的几何参数做了进一步优化，几何参数包括歧管半径、歧管角度和成型面高度，结合实际情况，如均匀性影响、纺丝效率和能源利用率，选出最适宜的几何参数。其次，根据熔喷原理和静电纺丝技术原理的不同，为
5、基础衣架模型添加纺丝针，设计出衣架式多针静电纺丝头，并研究纺丝液在其内部的流动情况，对衣架式多针静电纺丝头的入口部分、歧管部分、成型面部分和纺丝针部分的纺丝液压力分布情况给出一系列定量分析。再次，在上述研究的基础之上，采用已建立好的衣架式多针静电纺丝头进行模拟分析，对其模拟过程中的非牛顿指数、粘度、密度和流速等主要参数进行研究。在控制统一变量的情况下，设计单因子变量实验，考察各个参数分别对纺丝液的流动均匀性的影响。结合单因子实验设计正交实验，综合考虑模拟过程中主要参数对纺丝液流动均匀性的影响，最终得出较为全面的解决方案。最后，对新建立的衣架式静电纺丝头进行改善，根据纺丝液压力流动规律拟合出曲线
6、方程，建立曲面衣架式静电纺丝头。此外，结合多针头静电纺丝技术的场强分布规律，研究曲面衣架式静电纺丝头在高压静电场中的场强分布情况，并与衣架式静电纺丝头的场强分布情况进行对比，验证曲面衣架式静电纺丝头进行的合理性。关键词：衣架模型；静电纺；流体分配；流动均匀性；压力分布AbstractWith the preparation methods of nanofiber being researched and developed rapidly in recent years, nanofiber materials are widely used in many fields. Electros
7、pinning technology is one of the most effective methods for the preparation of nanofiber, which has the advantages for simple equipment, wide adaptability of raw materials and size control. At present, nanofibers by the electrospinning technology have achieved industrial production and application o
8、f in some fields. People have made lots of efforts to industrialize the electrospinning technology, such as improving the spinning head form, the receiving device and the polymer spinning and so on. However, few people try to improve the electrospinning technology in conveying solution angle, whats
9、more, it is urgent to solve the problem that the solution supply system exists the un-continuous liquid flowing, safe risk and other issues defects.The meltblown nonwoven technology is the most similar which can achieve the industrial production with the electrospinning technique. The most necessary
10、 die head part of meltblown equipment can feed liquid continuously and uniformly in the meltblown process, which not only improves the production efficiency, but also ensure the safety of the production quality. So we can learn from meltblown equipment of die technology, apply it to the supply and d
11、istribution of electrospinning spinning solution, and improve the uniformity of distribution of electrostatic spinning technology in spinning solution, laying the foundation for the industrialized production of the electrospinning technique. Due to coat-hanger die model is being widely applied in th
12、e meltblown technology, which was used in the electrospinning process of solution distribution uniformly in this study.Firstly, the COMSOL finite element software technique was adopted to simulate the electrospun solution flowing in the basic coat-hanger model. In order to enhance the solution distr
13、ibution uniformity of the model, the geometric parameters of the coat-hanger model were optimized, including the manifold radius, manifolds angle and molding surface height, and considering the actual situation with the uniformity, spinning efficiency and energy utilization rate, to select the optim
14、al parameters.Secondly, according to different principles of meltblown and electrospinning technologies, coat-hanger multineedles electrospinning head was designed by adding spinning needles for the basic coat-hanger, and studied solution flowing internally. Then, a series of quantitative analysis w
15、as done about solution pressure distribution on the inlet, manifold, forming surface and spinning needle part of the designed spinning.Third, the main factors including the non- Newtonian index, viscosity, density and velocity were studied on the basis of the simulation results of the above establis
16、hed multineedle coat-hanger electrospinning head. Under the control variables condition, the single factor experimental was designed and researched influence of the parameters for the solution flowing uniformity .On the basis of the single factor experiment, the orthogonal experiment came out to con
17、sider effects of the main parameters in the simulation process thoroughly, and ultimate design was achieved after analyzing the results.Finally, the electrospinning head of the newly established coat-hanger model was been improved, and then obtained the fitting curve equation according to regulariti
18、es of the pressure of solution flowing, building the electrospinning head of curved surface coat- hanger type. In addition, the combining with the rules of multi-needle electrospinning technology field distribution, the electric field intensity distribution in high voltage on the surface of the curv
19、ed surface coat-hanger spinning head was studied comparing with coat-hanger spinning head, to prove the rationality of the curved surface coat- hanger spinning head model.Keywords: coat-hanger model; electrospinning; fluid distribution; flowing uniformity; pressure distributionI目 录第一章 绪论 .11.1 研究背景
20、.11.2 静电纺丝技术简介 .21.2.1 静电纺丝技术原理 .21.2.2 静电纺丝技术的研究现状 .31.2.3 静电纺丝技术的改进 .41.2.4 工业化静电纺丝技术的研究 .61.3 非织造熔喷工艺 .81.3.1 熔喷技术的原理 .81.3.2 熔喷技术与静电纺技术的对比 .81.4 研究目的、内容、方案 .91.4.1 研究目的 .91.4.2 研究内容 .91.4.3 研究方案 .9第二章 流体均匀分配研究的相关理论 .112.1 流体动力学 .112.1.1 流体力学概述 .112.1.2 流体力学的研究方法 .122.1.3 流体的分类 .132.2 流体的粘弹性 .152
21、.2.1 剪切粘度 .162.2.2 表面张力 .162.2.3 松弛时间 .162.3 衣架模型 .172.3.1 基本的衣架模型 .172.3.2 研究衣架模型方法 .172.4 建模方程 .192.4.1 连续方程 .192.4.2 运动方程 .192.4.3 能量方程 .202.4.4 状态方程 .20第三章 基于衣架模型的静电纺流场模拟 .213.1 COMSOL 简介 .21II3.2 COMSOL 操作流程 .223.2.1 建立模拟项目 .223.2.2 建立衣架模型 .233.2.3 材料属性的设置 .233.2.4 设定求解域与边界条件 .233.2.5 划分网格 .233
22、.2.6 求解 .243.2.7 后处理 .243.3 纺丝溶液的参数 .253.3.1 配置溶液 .253.3.2 测试 .264.3 衣架模型的几何模型 .273.4 衣架模型的有限元分析 .283.4.1 非牛顿指数 .283.4.2 歧管角度 .293.4.3 成型面高度 .303.5 衣架式多针静电纺丝模头 .313.6 模拟结果分析 .323.6.1 入口区压力分析 .343.6.2 歧管到成型面区压力分析 .343.6.3 纺丝针区压力 .373.7 本章小结 .38第四章 静电纺丝溶液均匀分配的正交实验 .414.1 单因素实验 .414.1.1 非牛顿指数 .424.1.2
23、粘度 .454.1.3 密度 .464.1.4 流速 .474.2 正交实验 .504.2.1 方案设计 .504.2.2 实验结果分析 .524.3 本章小结 .54第五章 衣架式多针静电纺丝头的改善 .555.1 衣架式多针静电纺丝头的验证 .55III5.2 衣架式多针静电纺丝头的改善 .575.2.1 压力层曲线方程的拟合 .575.2.2 曲面衣架式静电纺丝头 .575.3 改善的有效性验证 .595.3.1 边缘效应 .605.3.2 场强模拟建模 .605.3.3 模拟结果分析 .615.4 本章小结 .64第六章 结论与展望 .656.1 结论 .656.2 展望 .65参考文献 .67发表论文和参加科研情况说明 .76致谢 .78IV
