【作者】 高博；

【导师】 李珊；

【作者基本信息】 昆明理工大学 ， 机械制造及其自动化， 2011， 硕士

【摘要】 近几年,我国年均铸件产量都在3000万吨以上,将铸造旧砂进行回收再生,可以减少环境污染和资源浪费,实现绿色生产。再生后的旧砂具有粒度均匀、表面光滑、耐热度好等优点,可以提高型砂和铸件的质量。目前的旧砂再生设备存在再生率低、砂粒破碎率高、耗能大、再生工艺繁琐、耗时长等缺点。因此需要寻找新的方法、开发新的设备来提高旧砂再生能力,满足旧砂再生的要求。旋流式旧砂再生装置的提出是以热法和气流式再生机理为基础,采用旋动射流的气流为动力源的新型旧砂再生装置。本文通过对不同旧砂再生方法优、缺点的对比指出干法是一种经济、有效的再生方法,而气流再生法又以其工作稳定、可靠,维修方便等优点已成为干法再生中的主流方法。通过对旋动射流相关理论的研究发现旋动射流的气体在强旋度的情况下存在很强的卷吸能力从而产生很强的掺混作用,这样会使砂粒与砂粒间发生相互摩擦,这有利于提高旧砂的再生效果。并根据横吹式旧砂再生机存在的砂粒易破碎、回收率低等现象和旋转的射流打击力随偏转角增大而递减的规律分析以后,提出了采用热法与旋动射流气流撞击法相结合的再生新方法。本文采用气流式旧砂再生机理及低温加热脆化方法针对粘土混合型旧砂的再生提出了旋流式旧砂再生装置的设计方案。在详细分析了旋流发生方式以后,采用管内导流法设计了该装置的旋流发生器。并通过Fluent软件的大量模拟仿真分析,得知圆弧板翼型叶片的导叶会使直流射流的气流产生强旋度的旋动射流。并指出在同一安装轴上,选择适当弧度、安装角、叶片数、弦长,叶片高度的圆弧板翼型叶片的旋流发生器,将产生更强旋度的旋动射流气流,并指出圆弧板翼型的安装角、弧度和叶片数量对气流的影响最强。又根据仿真结果提出入砂漏斗应尽量布置在靠近旋流发生器喷嘴的位置上,这有利于提高砂粒的流动速度和磋磨作用。并对入砂漏斗、入风口进行了详细的分析设计,使入砂量可以调节、入风口入风均匀。并应用Fluent软件提供的离散相模型,对砂粒的流动轨迹、流动速度进行了分析。最后对高速旋流旧砂再生设备的工艺步骤和优点做出了详细的分析。更多还原

【Abstract】 In recent years, Chinese annually casting output is above 30 million tons. Green sand reclamation can reduce environmental pollution and resources waste, and realize green production. Green sand reclamation have epigranular, smooth surface, good refractoriness and so on. That will improve foundry sand and casting quality.At present, green sand equipment exist low regeneration rate, high broken rate, high energy consumption, complex regeneration technology, persistent and so on. So a new method is needed to look for in order to improve green sand reclamation competent and meet the requirements of green sand reclamation. Rotary stream equipment for green sand reclamation base hot method and current reclamation mechanism. The new green sand reclamation equipment apply for rotary stream for power source.In this paper, by comparing advantage and disadvantage of different method of green sand reclamation, dry process is an economic and effective method. Air current regeneration have the advantages of steady, reliable and maintain. So it become the main method. By researching the theory of rotary stream jet, rotary stream jet air with strong rotation have strong entrainment ability and blending effect. The rotary stream jet air with strong rotation make green sand mutual scrub. That is in favor of reclamation effect. Transversal blow reclamation equipment exist the phenomenon of particles easily broken and low productivity. And it is found out that hitting power decrease with decrescence of deflection angle. So the new method of rotary stream green and hot process is proposed.In this paper, rotary stream equipment base current green sand reclamation mechanism and low temperatures heating method for clay combination green sand. After minutely analyzing rotary stream happened method, guide blade rotation method apply to the stream happened equipment in the equipment. And through plenty of simulation result of Fluent, guide blade leaf with rounded airfoil can produce strong rotary stream jet. On the same mounting axel, proper radian, installation angle, the number of leaves, length of chord, and height of leaf all can make strong rotary stream jet, especially radian, installation angle, and the number of leaves can make strong effect for rotation. By the result of simulation, the funnel of green sand should be fix up near the inlet of rotary stream happened equipment. That is in favor of green sand friction effect and raising green sand velocity. And By designing inlet of green sand funnel and intake of air, the quantity of green sand can be adjusted, and homogeneous quantity of air can be obtained. And By using dispersed phase model in Fluent, floating track and flow velocity of green sand is analyzed. Finally, processing step and advantage of the equipment with rotary stream in high speed is analyzed.更多还原