摘要
将模拟流场所用的Lattice Boltzmann方法(简称LBM)和模拟枝晶生长的相场模型进行耦合,模拟Al-Cu合金等温凝固过程中多晶粒在纯扩散和存在对流情况下枝晶的生长状况.模拟结果显示:在枝晶的生长初期,无论是纯扩散还是存在对流,各晶粒间间距较大,无相互影响,独立生长;纯扩散条件下枝晶呈现明显的对称性,强迫层流作用下,由于对流的存在,上游侧枝晶比下游侧枝晶发达;随着枝晶慢慢长大,各晶粒相互影响,产生竞争生长,导致枝晶生长产生不对称性;流速的大小会影响枝晶的生长形貌,流速越大,枝晶生长越快,非对称性越严重,下游越易产生涡流.
By coupling Lattice Boltzmann method for flow field simulation （LBM for short） with a phasefield model for dendrite growth simulation, the multiple grains growth was simulated for Al-Cu alloy during isothermal solidification in the case of pure diffusion and convection. The simulation result showed that, whether in the case of the former or the latter, there would be no influence of grains on each other, because the spacing between two grains was bigger without mutual influence, and they would grow independently. Dendrite shape was symmetric in the ease of pure diffusion. However, due to the existence of convection, the dendrite was bigger on the upstream side than that on the downstream side. Along with gradual dendrite growth, there would be influence among the grains and competitive growth took place, resulting in asymmetry of dendritic growth; The magnitude of flow velocity would affect the morphology of dendrite growth, the greater the flow rate, the faster the dendrite growth, and the more serious the asymmetry, so that in the downstream it would be easier to produce eddy current.
出处
《兰州理工大学学报》
CAS
北大核心
2014年第3期10-15,共6页
Journal of Lanzhou University of Technology
基金
国家自然科学基金(51161011
11364024)
甘肃省自然科学基金(1108ZSB096)
甘肃省科技支撑计划(120GKCA065)
关键词
LBM-PF
二元合金
等温凝固
多晶粒
强迫层流
竞争生长
LBM-PF
binary alloys
isothermal solidification
multiple grains
forced laminar flow
competitive growth
