工程科学学报，第38卷，第9期：1270-1277,2016年9月 Chinese Journal of Engineering,Vol.38,No.9:1270-1277,September 2016 D0l:10.13374/j.issn2095-9389.2016.09.011:http://journals.ustb.edu.cn 铝合金大铸锭超声半连铸多场耦合的数值模拟与实 验研究 徐 婷12四，张立华2)，李瑞卿2》，唐佳2》，黄诚2) 1)中南大学机电工程学院，长沙4100832)中南大学高性能复杂制造国家重点实验，长沙410083 ☒通信作者，E-mail:xuting_wangyi(@163.com 摘要建立了超声场下直径630m的铝合金大铸锭热顶半连铸过程中多场耦合的数学模型，采用有限体积法及自定义函 数获得超声作用下结晶器内声场、流场和温度场的分布，并进行工业化实验研究.综合工业实验和仿真结果分析超声对热顶 半连铸铝合金大铸锭细晶的机理。模拟结果表明，超声波对宏观物理场的影响非常明显，施加超声后，辐射杆端面下方形成 向上的回流区，强烈的紊流促进铝熔体的传质传热，减小液穴深度，使液穴更加平缓，同时初始凝壳点下移，过渡带变窄，铸锭 中心处过渡带宽度从342mm减小到120mm左右.分析实验结果发现，经超声处理，铸锭组织普遍变得细小、均匀，平均晶粒 尺寸减小103m,最大最小晶粒尺寸差从135um减小到64m,且凝固组织晶界变细. 关键词铝合金：超声波：铸造：耦合；数值模拟 分类号TG249.7 Numerical simulation and experimental study of multi-field coupling for semi-continuous casting of large-scale aluminum ingots with ultrasonic treatment XU Ting,ZHANG Li-hua,LI Rui-qing,TANG Jia,HUANG Cheng 1)School of Mechanical and Electrical Engineering,Central South University,Changsha 410083,China 2)State Key Laboratory of High Performance Complex Manufacturing,Central South University,Changsha 410083,China Corresponding author,E-mail:xuting_wangyi@163.com ABSTRACT A multi-field coupling mathematical model was established to analyze the hot-top semi-continuous casting of a large- scale aluminum alloy of 630 mm in diameter with ultrasonic treatment (UST).The finite volume method combined with the self-com- piled function was used to get the distribution of the acoustic field,flow field and temperature field,and the industrial experimental re- search was also performed.The mechanism of ultrasonic treatment on the grain refinement of the large-scale aluminum alloy produced by hot-top semi-continuous casting was analyzed based on the simulation and experiment results.The simulation results show that ultra- sonic markedly influences the macroscopic physic field.With ultrasonic treatment,an upward recirculation zone forms beneath the end face of the radiation rod,the heat and mass transfer is promoted by the strong turbulence,the sump gets shallower and gentler,the ini- tial solidifying point on the ingot surface in the mold moves down,the transition zone becomes narrower,the width of it in the center drops from 342 mm to nearly 120 mm.The experimental results show that with ultrasonic treatment,the grain size becomes smaller and more homogeneous,the average grain size reduces by 103 pm,the gap between the maximum and minimum grain size decreases from 135 to 64 um,and the grain boundary of the solidification structure becomes thinner. KEY WORDS aluminum alloys;ultrasonic:casting:coupling:numerical simulation 收稿日期：2015-10-05 基金项目：国家重点基础研究发展计划资助项目(2012CB619504):国家自然科学基金资助项目(51475480)工程科学学报，第 38 卷，第 9 期: 1270--1277，2016 年 9 月 Chinese Journal of Engineering，Vol． 38，No． 9: 1270--1277，September 2016 DOI: 10． 13374 /j． issn2095--9389． 2016． 09． 011; http: / /journals． ustb． edu． cn 铝合金大铸锭超声半连铸多场耦合的数值模拟与实 验研究 徐 婷1，2) ，张立华1，2) ，李瑞卿1，2) ，唐 佳1，2) ，黄 诚1，2) 1) 中南大学机电工程学院，长沙 410083 2) 中南大学高性能复杂制造国家重点实验，长沙 410083  通信作者，E-mail: xuting_wangyi@ 163． com 摘 要 建立了超声场下直径 630 mm 的铝合金大铸锭热顶半连铸过程中多场耦合的数学模型，采用有限体积法及自定义函 数获得超声作用下结晶器内声场、流场和温度场的分布，并进行工业化实验研究． 综合工业实验和仿真结果分析超声对热顶 半连铸铝合金大铸锭细晶的机理． 模拟结果表明，超声波对宏观物理场的影响非常明显，施加超声后，辐射杆端面下方形成 向上的回流区，强烈的紊流促进铝熔体的传质传热，减小液穴深度，使液穴更加平缓，同时初始凝壳点下移，过渡带变窄，铸锭 中心处过渡带宽度从 342 mm 减小到 120 mm 左右． 分析实验结果发现，经超声处理，铸锭组织普遍变得细小、均匀，平均晶粒 尺寸减小 103 μm，最大最小晶粒尺寸差从 135 μm 减小到 64 μm，且凝固组织晶界变细． 关键词 铝合金; 超声波; 铸造; 耦合; 数值模拟 分类号 TG249. 7 收稿日期: 2015--10--05 基金项目: 国家重点基础研究发展计划资助项目( 2012CB619504) ; 国家自然科学基金资助项目( 51475480) Numerical simulation and experimental study of multi-field coupling for semi-continuous casting of large-scale aluminum ingots with ultrasonic treatment XU Ting1，2)  ，ZHANG Li-hua1，2) ，LI Ｒui-qing1，2) ，TANG Jia1，2) ，HUANG Cheng1，2) 1) School of Mechanical and Electrical Engineering，Central South University，Changsha 410083，China 2) State Key Laboratory of High Performance Complex Manufacturing，Central South University，Changsha 410083，China  Corresponding author，E-mail: xuting_wangyi@ 163． com ABSTＲACT A multi-field coupling mathematical model was established to analyze the hot-top semi-continuous casting of a large￾scale aluminum alloy of 630 mm in diameter with ultrasonic treatment ( UST) ． The finite volume method combined with the self-com￾piled function was used to get the distribution of the acoustic field，flow field and temperature field，and the industrial experimental re￾search was also performed． The mechanism of ultrasonic treatment on the grain refinement of the large-scale aluminum alloy produced by hot-top semi-continuous casting was analyzed based on the simulation and experiment results． The simulation results show that ultra￾sonic markedly influences the macroscopic physic field． With ultrasonic treatment，an upward recirculation zone forms beneath the end face of the radiation rod，the heat and mass transfer is promoted by the strong turbulence，the sump gets shallower and gentler，the ini￾tial solidifying point on the ingot surface in the mold moves down，the transition zone becomes narrower，the width of it in the center drops from 342 mm to nearly 120 mm． The experimental results show that with ultrasonic treatment，the grain size becomes smaller and more homogeneous，the average grain size reduces by 103 μm，the gap between the maximum and minimum grain size decreases from 135 to 64 μm，and the grain boundary of the solidification structure becomes thinner． KEY WOＲDS aluminum alloys; ultrasonic; casting; coupling; numerical simulation