【作者】 古元军；

【导师】 曲迎东；

【作者基本信息】 沈阳工业大学 ， 材料加工工程， 2009， 硕士

【摘要】 雾化喷射成形技术既克服了传统铸造过程中存在的晶粒粗大、偏析严重的缺点,又摒弃了粉末冶金工艺中工序繁多,氧化严重等不足,是一种极具竞争力的快速凝固工艺。金属液滴雾化是决定喷射成形微观质量的关键技术,雾化器就成为喷射成形工艺的核心。为了解决以往自由式雾化器鼓包或者耦合式雾化器反喷的现象,本文在已有雾化器的基础上设计了一种新型自由式雾化器,确定了基于二级双层非限制式结构的新型自由式雾化器的结构,采用FLUENT对雾化器的工作参数进行了模拟,获得了工艺参数对雾化过程的影响规律,同时进行了实验验证。分析喷射成形雾化器及导液管的影响因素及各因素对雾化效果的影响,本文最终设计的新型二级双层非限制式雾化器的结构为环缝式,辅助雾化器和主雾化器的缝隙大小分别为0.3mm和0.5mm,主雾化器的雾化角为35°,辅助雾化器为0°。导液管的伸出距离为4mm,θ角为180°,导液管内径为4mm。对不同雾化压强下的雾化区域流场进行了模拟,并对各组情况下的压强及速度分布进行了比较,通过比较发现,当辅助雾化器的压强较大时能得到较大的负压,负压带主要受辅助雾化器的影响,雾化区域内的压强主要受主雾化器压强的影响。当主、辅雾化器的压强为1.0MPa、0.5MPa时,能得到较大的负压且不会出现鼓包的现象,当主雾化器的压强大于1.5MPa时有可能出现鼓包的现象。在上述数值模拟结果的基础上,对设定的几种不同压强下的雾化效果进行了实验分析。实验与模拟结果基本一致,当主雾化器的压强为1.0MPa,辅助雾化器的压强为0.5MPa时,能得到较好的雾化效果,主雾化器的压强较小时起不到明显的雾化效果,主雾化器的压强较大时(大于1.5MPa)将出现反喷的现象。此外,还分析了单主雾化器工作的情况,得出在相同结构下,普通自由式雾化器所允许的最大压强小于0.7MPa。更多还原

【Abstract】 Atomizing spray forming technology not only overcomes the shortcomings of coarse grain and serious segregation in the traditional casting process but also abandons some shortcoming in powder metallurgy process, such as complicated processes and serious oxidation, so it is very competitive in rapid solidification process. During spray forming, metal droplets atomizing is the key to the quality of micro-technology, so atomizer becomes the core of the spray forming process. In order to Solve the drum packets phenomenon of freestyle atomizer or anti-spray phenomenon of coupled atomizer, this article designed a new type unrestricted atomizer, determined the structure of new freestyle atomizer based on structure of double-decked unrestricted atomizer, combined with the CFD software FLUENT got the influence rule of technological parameter to atomization process and did some experimental verification..By analyzed the factors of atomizer and catheter and the impact of these factors on atomization, the final structure of the atomizer was designed as circle-shaped gap, the gap size of main atomizer and the auxiliary atomizer is 0.3mm and 0.5mm, the atomization angle of main atomizer and the auxiliary is 35°and 0°. The catheter extend distance is 4mm,θis 180°, inner diameter is 4mm.Did some simulation to the atomization region under different pressure, and did some analysis of pressure and velocity distribution, the results show, when the auxiliary atomizer’s pressure become greater can get big negative pressure, negative pressure zone is mainly affected by the impact of auxiliary atomizer and pressure of the atomization region is mainly affected by the main pressure atomizer. When main atomizer’s pressure is 1.0MPa and the auxiliary atomizer’s pressure is 0.5MPa, can get big negative pressure and not appear drum packets phenomenon, when main atomizer’s pressure is higher than 1.5MPa, drum packets phenomenon may appear. On the basis of numerical simulation results, this article did some experimental analysis of several different kinds of pressure. The experimental results are consist with the simulate conclusions, when main atomizer’s pressure is 1.0MPa and the auxiliary atomizer’s pressure is 0.5MPa, can get a good atomization phenomenon, when the main atomizer’s pressure is too low, atomization phenomenon is not good, when the main atomizer’s pressure is higher than 1.5MPa drum packets phenomenon may appear. In addition, experiment was did when only the main atomizer working, result shows, at the same structure, the main atomizer’s pressure is no more than 0.7MPa更多还原