铜合金熔体泡沫陶瓷离心过滤净化数值模拟与实验研究

发布时间：2018-08-12 16:54

【摘要】：铜合金作为一类重要有色金属材料,在国防和电力等工业中被广泛地应用。随着科学技术和工业生产的不断进步,对铜合金洁净度的要求日益提高。泡沫陶瓷过滤技术被公认为是去除合金熔体中非金属夹杂物的有效方法。为了滤除更加细小的夹杂物而采用小孔径、大厚度的泡沫陶瓷过滤器时,由于过滤阻力增大影响了过滤速度,甚至难以完成过滤过程。合金熔体泡沫陶瓷离心过滤技术是一种新的过滤净化方法,它借助离心力使合金熔体通过孔径更小、厚度更大的泡沫陶瓷过滤器,从而提高过滤效率和过滤速度。本文以铜合金熔体泡沫陶瓷离心过滤工艺为研究对象,采用实验及数值模拟方法进行研究。实验研究了过滤温度、离心转速、泡沫陶瓷孔径和泡沫陶瓷厚度等过滤工艺参数对过滤效果的影响;通过SEM技术获取泡沫陶瓷几何结构参数,采用WeairePhelan泡沫模型构建了接近实际泡沫陶瓷结构的三维模型,利用数值模拟方法研究了铜合金熔体在不同过滤工艺参数条件下,过滤阻力和过滤效率变化规律。通过实验研究和数值模拟,得到如下主要结论:(1)过滤实验和数值模拟结果表明,泡沫陶瓷离心过滤与重力过滤相比,离心过滤借助于离心力,可采用孔径更小、厚度更大的泡沫陶瓷过滤器对合金熔体进行过滤,有利于提高铜合金洁净度和过滤速度,提高铜合金的力学性能。(2)数值模拟结果表明,泡沫陶瓷结构参数是影响过滤效率和过滤阻力的主要因素。各因素对过滤效率的影响强弱顺序是:泡沫陶瓷孔径泡沫陶瓷厚度离心转速过滤温度;影响过滤阻力强弱顺序是:泡沫陶瓷孔径泡沫陶瓷厚度。提高离心转速有利于克服流动阻力,提高过滤温度有利于克服热阻。(3)Weaire-Phelan模型是公认的最具代表性的泡沫几何结构模型之一。构建以Weaire-Phelan模型为基本骨架的泡沫陶瓷三维几何模型,关键是准确获取泡沫陶瓷的结构参数和Plateau边界处理。(4)数值模拟结果和过滤实验规律基本吻合,两者之间出现较小偏差的原因是,在进行数值模拟过程中没有考虑合金熔体、夹杂物和泡沫陶瓷三者之间的界面行为和熔体对已捕捉夹杂物的冲刷作用。数值模拟结果对优化铜合金熔体泡沫陶瓷离心过滤工艺具有一定指导意义。
[Abstract]:As a kind of important nonferrous metals, copper alloy is widely used in national defense and power industry. With the continuous progress of science and technology and industrial production, copper alloy cleanliness is increasingly required. Foam ceramic filtration technology is recognized as an effective method for removing non-metallic inclusions in alloy melts. When the foam ceramic filter with small pore diameter and large thickness is used to filter the smaller inclusions, the filtration speed is affected by the increase of the filtration resistance, and the filtration process is even difficult to complete. The centrifugal filtration technology of alloy melt foam ceramics is a new method of filtration and purification. It makes alloy melt pass through foam ceramic filter with smaller pore diameter and thicker thickness with the aid of centrifugal force, thus increasing the filtration efficiency and filtering speed. In this paper, the centrifugal filtration process of copper alloy melt foam ceramics was studied by means of experiment and numerical simulation. The effects of filtration process parameters such as filtration temperature, centrifugal speed, pore diameter and thickness of foam ceramics on the filtration effect were studied experimentally, and the geometric structure parameters of foam ceramics were obtained by SEM technology. WeairePhelan foam model was used to construct a three-dimensional model of ceramic foam structure. The variation of filtration resistance and filtration efficiency of copper alloy melt under different filtration parameters was studied by numerical simulation. Through experimental research and numerical simulation, the main conclusions are as follows: (1) the results of filtration experiment and numerical simulation show that, compared with gravity filtration, foam ceramic centrifugal filtration can adopt smaller pore size by means of centrifugal force. The foam ceramic filter with thicker thickness can improve the cleanliness and filtration speed of the alloy and improve the mechanical properties of the alloy. (2) the numerical simulation results show that, The structure parameters of foam ceramics are the main factors affecting filtration efficiency and filtration resistance. The influence of various factors on the filtration efficiency is in the order of the thickness of foam ceramic aperture foam ceramic thickness centrifugal speed filtration temperature and the order of influence of filtration resistance is: foam ceramic pore diameter foam ceramic thickness. Increasing the centrifugal speed is beneficial to overcome the flow resistance and increasing the filtration temperature to overcome the thermal resistance. (3) Weaire-Phelan model is recognized as one of the most representative foam geometry model. The key to construct a three-dimensional geometric model of foam ceramics based on Weaire-Phelan model is to accurately obtain the structural parameters of foam ceramics and the Plateau boundary treatment. (4) the results of numerical simulation are in good agreement with the laws of filtration experiments. The reason for the small deviation is that the interface behavior of alloy melt, inclusions and foam ceramics and the scour of the trapped inclusions are not taken into account in the numerical simulation. The numerical simulation results have certain guiding significance for optimizing the centrifugal filtration process of copper alloy melt foam ceramics.
【学位授予单位】：南昌航空大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ028.53

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