【作者】 邹永生；

【导师】 丁泽良；

【作者基本信息】 湖南工业大学 ， 机械设计及理论， 2009， 硕士

【摘要】 水煤浆喷嘴不耐磨、使用寿命短一直是水煤浆应用技术中有待解决的关键性难题之一。本文融合梯度功能材料的设计理论、有限元分析、喷嘴技术于一体,对梯度功能陶瓷水煤浆喷嘴的设计、制备、性能检测以及磨损特性进行了系统地研究。在分析均质陶瓷水煤浆喷嘴工作特性和损坏机制的基础上,提出了梯度功能陶瓷水煤浆喷嘴的设计思路和设计方法。根据梯度功能陶瓷水煤浆喷嘴的物理模型,选择Al2O3/(W,Ti)C材料体系作为喷嘴的制作材料,通过材料物性参数的计算和组分分布模型,确定了梯度功能陶瓷水煤浆喷嘴的初步模型。采用有限元方法,深入分析了梯度功能陶瓷水煤浆喷嘴制备过程中形成的残余应力与梯度层的厚度、层数及烧结温度之间的关系,并确定了两种梯度功能陶瓷水煤浆喷嘴的理论模型。采用热压烧结法成功制备了Al2O3/(W,Ti)C材料系两种梯度功能陶瓷水煤浆喷嘴,即单向梯度功能陶瓷水煤浆喷嘴(型号DXPZ)和双向梯度功能陶瓷水煤浆喷嘴(型号SXPZ);为对比研究,同时制备了均质陶瓷水煤浆喷嘴(型号JZPZ),并对三种喷嘴材料性能进行了测试。结果表明,梯度功能陶瓷水煤浆喷嘴烧结良好,致密化程度较高;其力学性能明显优于均质功能陶瓷水煤浆喷嘴,且与梯度层数有密切关系。对三种陶瓷水煤浆喷嘴进行了现场磨损试验,对比研究了喷嘴的重量损失、孔径变化以及磨损后的宏观形貌、微观形貌。根据喷嘴磨损后的孔径及冲蚀磨损量的变化,初步估算三种喷嘴的使用寿命为: JZPZ喷嘴>2100h,DXPZ喷嘴>3500h,SXPZ喷嘴>4100h。在相同的试验条件下,双向梯度陶瓷喷嘴SXPZ的抗热冲蚀性能较好,单向梯度陶瓷喷嘴DXPZ次之,均质陶瓷喷嘴JZPZ较差。研究结果表明,本文提出的梯度功能陶瓷水煤浆喷嘴的设计思路正确,应用效果好。更多还原

【Abstract】 Poor resistance to wear, short working life of coal water slurry(CWS) nozzles are critical problems with the using of coal water slurry to be solved. According to the design theory of functionally graded materials, FEM analysis, nozzle technology, functionally graded ceramic CWS nozzles were designed and prepared, its properties were tested and its wear and failure characteristics were investigated.The design philosophy and methods of functionally graded ceramic CWS nozzles were advanced after their working and failure characteristics were analyzed. Based on the physical models of functionally graded ceramic CWS nozzles, the materials of Al2O3/(W,Ti)C were selected to make the nozzles. The initial geometric models were fixed according to the computation to the physical parameters and components distribution of the materials. The FEM was adopted to analyze the relationships between the residual stresses of the nozzles and the thickness, strata number, sintering temperature of the gradient layers in the preparing process of the nozzles. Two theoretical models of functionally graded ceramic CWS nozzles were achieved.Two kinds of functionally graded ceramic CWS nozzles were prepared with the hot pressing method. They are directional functionally graded ceramic CWS nozzle(DXPZ), and bidirectional functionally graded ceramic CWS nozzle(SXPZ) respectively. To compare with them, homogeneous ceramic CWS nozzles(JZPZ) were prepared at the same time. The material properties of the three kinds of nozzles were tested. The tested results showed that functionally graded ceramic CWS nozzles were sintered well and very compact. Their mechanical properties were better than that of homogeneous ceramic CWS nozzles and related with the strata number of the gradient layers.Practice wear tests were performed with the three kinds of nozzles. The weight loss, the aperture changes, the worn macro and micro appearances of the nozzles were investigated and compared. According to aperture changes of the nozzles, the forecasted working life of the three kinds of nozzles was more than 2100h of JZPZ, 3500h of DXPZ, 4100h of SXPZ respectively.Under the same experimental condition, the thermal erosion resistance of the bidirectional functionally graded ceramic CWS nozzles(SXPZ) was better than that of the directive ones which was better than that of the homogeneous ones.The research results showed that the design ideas of functionally graded ceramic CWS nozzles were corrective and could be used in working practices.更多还原