大型搅拌槽叶轮形状对矿浆浓度分布影响的研究

发布时间：2018-06-07 11:00

本文选题：矿浆搅拌 + 三维模拟　；参考：《沈阳工业大学》2017年硕士论文

【摘要】：矿浆搅拌槽是浮选生产工艺中不可缺少的重要设备之一,搅拌槽的性能好坏决定了浮选的效率和矿石的产能。随着工业加工能力的提高,搅拌设备的大型化成为一种必然趋势,并且在冶金、化工行业广泛应用。对于大型机械搅拌混合设备来说,机械能通过搅拌槽搅拌叶轮的旋转转化为流体的动能,从而完成槽体内流体的流动,完成物质交换和热交换的过程。搅拌槽内流体流动形式与搅拌叶轮形状和槽体内部结构密切相关,大型搅拌槽的搅拌的叶轮直径,扭矩和弯矩都很大,并且还会受到搅拌介质、搅拌叶轮形式、施工质量和搅拌效果影响,因此对搅拌槽内流体流动的规律的深入了解和对搅拌桨叶轮的形状设计是搅拌设备优化设计的基础。随着计算机技术的发展,计算流体力学(CFD)已成为研究搅拌设备内部流场和研究多相流领域的重要方法。本文基于两相流欧拉原理对大型矿浆搅拌槽内部流场分布进行了三维模拟,深入研究了单层三种不同叶轮形式的搅拌叶轮和单双层同种叶轮形式的搅拌叶轮对大型矿浆搅拌槽矿浆体积分数分布的影响。数值分析结果表明,大型矿浆搅拌槽在搅拌过程中会在搅拌叶轮中心形成一个负压区,在负压区的四周会产生不同旋转方向的涡流。矿浆流速的最大值出现在搅拌叶轮的外径最大处且标准三叶推进式叶轮在外径最大处流速最小,紊流效应也最小;在同种转速和相同矿浆体积分数的条件下,同样是单层的标准六叶直叶片式叶轮和双层六斜叶开启涡轮式叶轮在搅拌过程中都会在槽底有矿浆颗粒沉降的现象出现,矿浆体积分数分布不均,而标准三叶推进式叶轮和双层标准六叶直叶片式叶轮矿浆体积分数混合均匀,搅拌混合效果最好。
[Abstract]:Slurry mixing tank is one of the indispensable equipment in flotation process. The performance of mixing tank determines the efficiency of flotation and the productivity of ore. With the improvement of industrial processing capacity, the large-scale agitation equipment has become an inevitable trend, and widely used in metallurgy and chemical industry. For large mechanical mixing equipment, the mechanical energy can be transformed into the kinetic energy of the fluid by rotating the impeller in the stirring tank, thus completing the flow of the fluid in the tank and the process of material exchange and heat exchange. The flow form of fluid in the stirred tank is closely related to the shape of the impeller and the internal structure of the tank. The impeller diameter, torque and bending moment of the large stirred tank are very large, and it will also be subjected to the stirring medium and impeller form. Because of the influence of construction quality and agitation effect, it is the foundation of optimization design of mixing equipment to deeply understand the fluid flow law in the mixing tank and to design the shape of the impeller. With the development of computer technology, computational fluid dynamics (CFD) has become an important method to study the flow field in mixing equipment and the field of multiphase flow. In this paper, based on the Euler principle of two-phase flow, the flow field distribution in a large slurry mixing tank is simulated. The effects of three single-layer impellers with different impellers and the same impellers with single and double-layer impellers on the volume fraction distribution of large slurry mixing tanks were studied. The numerical results show that a negative pressure zone will be formed in the center of the impeller in the mixing process of the large slurry mixing tank and a swirl with different rotation directions will be produced around the negative pressure zone. The maximum velocity of slurry appears at the maximum external diameter of the impeller, and the standard three-leaf impeller has the smallest velocity and the least turbulent effect at the maximum diameter, and under the same speed and the same volume fraction of slurry, the maximum velocity of the impeller is the same as that of the impeller. The same single-layer standard six-leaf straight vane impeller and double-declined-blade turbo impeller will all have slurry particle settlement at the bottom of the trough during stirring process, and the volume fraction of slurry will be distributed unevenly. However, the volume fraction of standard three-leaf impeller and double standard six-leaf straight blade impeller is uniform, and the mixing effect is the best.
【学位授予单位】：沈阳工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TD45

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