Li Xiaoqian, Zhao Shilian, Xie Enhua, et al. Analysis of Flow Field in the Mould and Experiment Verification on Semi-continuous Casting Aluminum Alloy under Ultrasonic Treatment. [J]. Special Casting & Nonferrous Alloys 30(2):157-160(2010)
Li Xiaoqian, Zhao Shilian, Xie Enhua, et al. Analysis of Flow Field in the Mould and Experiment Verification on Semi-continuous Casting Aluminum Alloy under Ultrasonic Treatment. [J]. Special Casting & Nonferrous Alloys 30(2):157-160(2010)DOI:
Analysis of Flow Field in the Mould and Experiment Verification on Semi-continuous Casting Aluminum Alloy under Ultrasonic Treatment
摘要
利用CFD商用软件FLUENT建立了7050铝合金超声半连铸圆坯结晶器的有限体积模型
运用动网格模型对超声作用下的结晶器流场进行分析
重点研究了超声声流现象对结晶器流场的影响。结果表明
在由于粘滞衰减产生声压梯度而形成的超声辐射力的作用下
熔体形成大规模的Eckart声流现象。由于声流速度幅值相比结晶器流场速度幅值和规模很小
因此其对结晶器流场无明显影响。在超声半连铸试验中
浇口流场所形成的涡流把超声工具杆端面下空化作用形成的等轴晶和有效形核质点转移到液穴的其他区域
并且把液穴内远离空化区的熔体带入工具杆空化区域形成新的形核质点
如此往复
在整个铸锭截面内都形成了等轴晶组织。声流场对于超声细晶区域的扩大作用很小
因此可以忽略不计。
Abstract
The FEM model of the mould for 7050 aluminum semi-continuous casting round billets was built up by CFD software Fluent
and flow filed of the aluminum alloy melts sonicated in the mould was analyzed
focusing on effects of acoustic streaming on the flow field. The results reveal that large-scale Echart acoustic streaming was formed in the liquid phase zone
driven by the radiation force which was formed as a result of the acoustic pressure gradient resulting from the viscous attenuation. As the amplitude and the scale of the Eckart acoustic streaming were much smaller than those of the flow field in the mould
effects of acoustic streaming on the flow filed can be neglected. The vortices from the flow field in nozzle transfer the effective nuclei and equiaxed grains formed in the cavitation area to the other area of the liquid pool and brings the other melt to the cavitation area in turn
forcing the others to be equiaxed grains and effective nuclei
finally
the structures of the ingot are all equiaxed grains. Effects of acoustic streaming on enlarging the refinement area can be negligible in the semi-continuous casting experiment.
关键词
半连铸结晶器超声波流场辐射力声流细晶区域
Keywords
Semi-continuous CastingMouldUltrasonicFlow FieldRadiation ForceAcoustic StreamingRefinement Area