【作者】 张文明；

【导师】 刘彬； 李海滨；

【作者基本信息】 燕山大学 ， 仪器科学与技术， 2010， 博士

【摘要】 提高水泥生产过程中的能量回收,降低水泥吨能耗,是国内外水泥工业目前需要解决的核心问题。篦冷机熟料冷却效率对水泥的质量和热量回收再利用有着重要的意义,水泥熟料的冷却控制水平直接决定着热回收效率。建立准确的冷却控制模型是提高冷却控制技术的前提,是实现节能降耗并向绿色水泥发展的关键。本课题以篦冷机热交换系统为研究对象,针对熟料三维重建、三维网格划分和三维气固换热特性等方面问题进行深入研究,建立熟料流动状态下三维网络控制模型。通过实验验证控制模型的正确性。具体工作包括:研究水泥熟料冷却过程中熟料流动与空气流动特性,基于双目立体视觉技术对熟料进行三维重建。提出了基于二进小波变换的子线段匹配方法,采用由粗到细的匹配策略进行点对点匹配。仿真结果证明该方法具有较好的准确性与快速性,重建后的熟料三维形体满足进一步网格划分的需要。提出基于几何特征和物理特征的三维网格划分加密规则,以熟料颗粒、温度、厚度和冷却风量的变化率作为评价尺度设计了熟料自适应网格划分算法,通过对对象的加密区域、区域布点等前期处理,选取最佳节点,从而对熟料三维重建后的三维体进行网格自动生成,并对特征区域进行局部加密。根据气固两相流换热理论和流体动力学原理,基于自适应网格划分模型,对熟料流动冷却状态下换热特性进行研究,分析熟料厚度与颗粒直径波动对换热的影响;根据气固两相流颗粒受力的研究,建立熟料流动状态下颗粒碰撞的动力学模型,并对熟料颗粒运行轨迹进行仿真试验和实验平台试验对比,验证了模型的有效性。研究熟料温度场与冷却风量、熟料运动速度、熟料厚度之间的数学关系,构建包含熟料微元换热信息的网格节点热平衡方程。通过对熟料冷却过程控制机理的研究,建立熟料多阶段冷却温度模型,并深入研究了熟料网格单元的对流换热及辐射换热所产生的温降模型,熟料冷却过程中特征参数之间内在联系,建立熟料冷却的三维网络控制模型,实现对冷却风量和熟料温度、厚度的控制。针对控制模型进行实验分析,实验结果验证了控制模型的有效性。更多还原

【Abstract】 The core issue of the cement industry which is needed to be solved at home and abroad is that improving the energy recovery of the cement production process in order to reduce the ton energy consumption of cement. The cooling efficiency of grate cooler clinker has vital significance for the quality and heat recovery of the cement. The heat recovery efficiency is directly determined by the cooling control technology of grate cooler clinker. The establishment of an accurate cooling control model is the precondition of improving the coolling techonology, and the key of saving energy sources in order to develop of green cement. In this paper the research object is the heat-exchange system of grate cooler. Researching characteristics issue of reconstruction, grid partition, and as solid heat transfer in the three dimension, the three dimensional network control model is established under the flow state of clinker. The accuracy of the control model is verified through the experiments. Specific tasks include:Research on the flow characteristics of the clinker and the air in the cooling process of the grate cooler clinker, the three dimensional reconstruction is done to the clinker based on the technology of binocular vision. Subline matching method based on binary system small wave transform is proposed which use the matching scheme from thick to thin for point matching. Simulation results show that the method has better accuracy and speed, and the three-dimensional shape of the clinker after the reconstruction meet the need for further analysis.The three dimensional mesh generation encryption rule is proposed based on the geometry characteristics and the physical characteristics. The auto-adapted mesh generation algorithm of clinker is designed, the evaluations of which are the clinker particles, temperature, thickness and chang rate of cooling air volume. The best node is selected based on the earlier period processing of encryption, regional points according to the node encryption rule. Then the three dimensional mesh is generated automatically, and carries on the local encryption to the characteristic area.According to heat transfer theory and the hydrodynamics principle, based on the auto-adapted mesh generation model, this paper studies the heat transfer characteristics under the state of cooling and flow, analysises the influence of clinker thickness and the pellet diameter undulation to the heat transfer. According to the research of two phase currents pellets stress, the dynamics model is established in the state of the pellet collision. And comparing the simulation of clinker particle trajectories and the experiment platform to verify the accuracy of the model.The grid node thermal equilibrium equation that encompasses the clinker heat transfer information is established based on the research on the mathematical relation of grate cooler clinker temperature field and the cooling air volume, the clinker velocity of movement, and the clinker thickness. The multi-phases clinker cooling temperature model is obtained through the research of cooling control mechanism. The inner link between the characteristic parameters of the clinker cooling process have been found after the indepth study of the temperature drop model that is caused by the counter-flow heat transfer and the radiation heat transfer of the clinker grid unit. Then the three dimensional network control model of cooling clinker is established. Analysing the experiment of the control model, the results verify the accuracy of the control model.更多还原