【作者】 陈光伟；

【导师】 花军；

【作者基本信息】 东北林业大学 ， 机械设计及理论， 2012， 博士

【摘要】 纤维板生产中,纤维原料的制备主要采用热磨法。热磨法是对纤维原料进行短时高温蒸煮后,利用磨片对原料的研磨作用促使纤维细胞迅速发生解离、转变为单体纤维的生产方法。揭示热磨法磨片纤维分离机理可以深入地开展纤维板生产工艺理论研究,建立完善的纤维分离理论；在技术层面上优化磨片的齿形结构,提高磨片的性能及其纤维制备质量和效率,有助于纤维板生产中的节能降耗。因此,热磨法磨片纤维分离机理的模型分析与实验研究具有重要的理论意义和实际应用价值。本文根据植物纤维原料的种类和结构特性,纤维板生产工艺与设备构成,结合磨片的结构特征,分析说明了齿形结构参数对磨片纤维分离机理的影响；根据纤维原料的渐进式破碎和解离过程,分析了磨片破碎区、粗磨区和精磨区的作用机理,以及纤维原料在各区域的受力方式、强度及频率,推演了纤维原料逐步分离为纤维的进程,从宏观力学角度对磨片的纤维分离机理进行了分析研究。本文应用流体力学理论,对磨片的纤维分离机理进行了模型分析。根据流体运动学理论,将纤维视为粘性流体物质,参考纤维分离过程的工况参数,提出了纤维流体密度、粘性的计算方法。建立了关于磨片间隙、磨齿倾角和齿槽宽度等磨片齿形结构参数的纤维运动模型,获得了表达纤维剪切流动基本规律和流场形式的数学描述；分析了边界层和磨齿粗糙表面对纤维运动速度的影响,磨片间隙和磨齿倾角对纤维运动规律的影响,以及齿槽宽度对纤维流量的影响,初步揭示了上述参数在磨片纤维分离机理中的作用机制。本文根据纤维制备的生产工艺与设备状况,对影响纤维分离质量和能耗的外部因素进行了分析。根据流体动力学理论,建立了关于磨片齿形结构参数和纤维运动参数的热磨机功率消耗的数学模型,提出了纤维分离过程中热磨机能量消耗、以及纤维流动过程中能量损失的理论模型,分析了磨片齿形结构参数对纤维分离能耗的影响。基于磨片结构的设计参数与纤维制备的能耗控制参数,提出了衡量磨片纤维分离性能的评价参数,建立了磨片齿形结构参数、磨片性能以及纤维分离质量与能耗之间的联系。本文通过纤维板生产实际的实验研究,分析了排料阀开度OV、出料螺旋转速SR、料位高度CH等热磨机工作参数对纤维质量QF、比能耗SEC和纤维产量TF的影响,在大样本条件下多元回归了三个影响因子对三个目标函数的统计关系式。根据三种纤维样本的形态尺寸测量数据,与对应的三种实验磨片齿形结构特征的对比统计,实验验证了磨片齿形结构差异对纤维形态尺寸的影响,以及磨片性能参数与纤维形态质量之间的关联性。热磨法磨片纤维分离机理的模型分析与实验研究,深入剖析了磨片在纤维分离中的作用,利用模型分析方法明确了磨片齿形结构参数的作用机制,为磨片齿形结构的优化设计提供了理论基础和技术支持,提高了我国热磨法纤维分离理论的研究水平：为优化纤维制备工艺、创新设计纤维分离设备,为进一步提高纤维板制品质量,实现生产中的节能降耗提供了可靠保障。更多还原

【Abstract】 In fiberboard production, the preparation of fibers is mainly by thermomechanical refining method. This method uses the refining plate to exert refining effect to the raw materials after a short time high-temperature steaming, which contributes to the disintegration of fiber cells of raw materials, then the raw materials change into monomer fibers. Reveal the fiber separation mechanism can deeply carry out the study on the theory of fiberboard production technology, establish a prefect fiber separation theory; optimize the plate tooth structure in technology level, improve the performance of the refining plate and the quality and efficiency of fiber separation and help the energy-saving during fiberboard production. Therefore, the model analysis and experimental study on fiber separation mechanism has an important theory significance and application value.According to the fiber type and the structure characteristic of raw materials, as well as the fiberboard production technology and equipments, and combining with the characters of plate tooth structure, this paper analyzed the refining plate tooth structure influence to the mechanism of fiber separated. According to the progressive broken and dissociation process of the raw materials during fiber separation, this paper analyzed the mechanism of crush zone, coarse zone and finishing zone, as well as the forced form, strength and frequency in different zones, developed the process that the raw materials from wood chips gradually separated into fibers, analytical studied the mechanism of refining plate separated fiber in macroscopic mechanics.Using the hydrodynamics theory, this paper made a model analysis on the mechanism of refining plate separated fiber. According to the fluid kinematics theory, fibers were treated as viscous fluid, referencing to the refining technological parameters, calculation methods of density and viscosity of fiber fluid were put forward; Established a movement model including the gap, the bar angle and the width of groove, etc, and the mathematical expression of the basic rule of fiber shear flow and flow forms were obtained. Analyzed the boundary layer and the rough surface of bar influence to the velocity of fiber, the gap and the bar angle influence to the rule of fiber flow as well as the width of groove influence to the fiber flow, revealed the mechanism of these parameters in the process of refining plate separating fiber preliminarily.Combining with the fiberboard production technology and equipments, the external factors is analyzed that have influence on the quality of the fiber separated and the energy consumption in this paper. According to the fluid dynamics theory, established a mathematical model of refiner power consumption about the structure parameter of plate tooth and the motion parameter of fiber, put forward a theory model about energy consumption of the refiner and power loss of the fiber flow in the process of fiber separated, analyzed the function of refining plate tooth structure influence to the energy consumption. Based on the design parameter of plate tooth structure and the control parameter in fiber preparation, this paper put forward the evaluation parameters measuring the performance of refining plate and concurrently established the contact among the parameter of plate tooth structure, the performance of refining plate and the fiber separation quality and energy consumption.Through the experimental study on the fiberboard production, this paper analyzed the influence the opening ratios of the discharge valve (OV), the feeding screw revolution speed (SR) and the accumulated chip height (CH) to the qualified fibers(QF) and the specific energy consumption (SEC) and the total amount of fibers (TF), used multiple regression analysis method, the statistic regression equations between the predictor variables and the response variables were obtained in large sample condition. According to the measurement data of fiber size in the three samples compared with the corresponding tooth structure characters of three experimental refining plate, this paper analyzed the difference in tooth structure of refining plate influence to the dimension of fiber and the relationship between the performance of refining plate and fiber quality.The model analysis and the experimental study on mechanism of fiber separation deeply analyzed the function of refining plate during fiber separation, making clear of the working mechanism of the tooth structure parameter of refining plate by model analysis method, it provide the theoretical basis and technical support for the optimization design the tooth structure of refining plate and improved the study level of domestic thermomechanical fiber separation theory, and it provided a reliable guarantee for the optimize of fiber preparation technology and the innovation design of fiber separation equipment, and for the further improve of fiberboard quality and the energy-saving in production.更多还原