【作者】 薛微微；

【导师】 王德庆；

【作者基本信息】 大连交通大学 ， 材料学， 2006， 硕士

【摘要】 本文分别以室温时静态和动态条件下的泡沫铝发泡过程为对象进行水模拟实验研究。在水模拟实验过程中，通过改变影响发泡过程中气泡特性的参数，如入射气体的流量、压强、出气孔直径、数量、液体的深度、粘度、密度、气液间表面张力、发泡室体积、搅拌轴在发泡室长度方向上的位置以及搅拌速度等，获得气泡直径随参数改变的变化规律，从而建立静态和动态发泡条件下气泡直径的预测模型。 在静态实验模拟部分，根据水模拟实验过程中观察到的现象，入射压缩空气进入液体后形成气泡脱离出气孔向液面运动的过程分为连续运动和非连续运动两部分。以入射空气在聚乙烯醇水溶液中的变化运动过程为基础建立静态模型。而动态模型则是在静态模型的基础上考虑影响铝泡沫形成过程的动态因素对气泡形成的影响。 根据静态和动态气泡直径预测模型计算得到的结果可准确地用于预测不同发泡条件下闭孔泡沫铝胞直径。根据水模拟实验结果，气泡直径随着入射气体的流量、压强、出气孔直径、液体深度以及发泡室体积的增大而增大，随着液体粘度、出气孔数量、搅拌速度以及液体密度等参数的增大而减小，表面张力对直径的影响甚小。 利用铝熔体空气发泡实验对水模拟实验获得的预测模型进行验证，结果证明模型预测值和实验值符合得较好。更多还原

【Abstract】 Room temperature three-dimensional static and dynamic simulations of bubble formation process were conducted in a polyvinyl alcohol solution in order to predict foam size of a closed cell aluminum foam produced by air-foaming aluminum melt. During the simulations, variables which affect liquid flow nature and bubble characteristics were investigated by the numbers.According to the formation and flow of bubbles in the quiescent PVA solution, the static model is established based on the continuous and noncontinuous flow processes of a single bubble flow from the orifice to the top surface of the solution. Moreover, the dynamic model is founded by simply applying the effects of dynamic factors on static model and includes all the geometric, physical and hydro mechanical factors of processing the aluminum foam.The calculated results obtained with the static and dynamic models are capable of accurate predicting the bubble size under varied conditions of processing the closed cell aluminum foam. According to the result of the static and dynamic simulation experiments, the bubble diameter is increased with the air flow rate and air pressure, orifice diameter, liquid depth and volume of the foaming-chamber, and decreased with liquid viscosity and density, number of orifices, shaft speed. Moreover, surface tension has little effect on the bubble diameter.The resulting numerical model of predicting foam size of the closed cell aluminum foam was verified by comparison to the results from practical foaming process at different production conditions, and the predicted foam size is in good agreement with the experimentally determined ones.更多还原