壁面加热对微圆柱漩涡脱落的影响  

Impact of heating wall on vortex shedding of micro-cylinders

作　　者：管宁[1] 刘志刚[1] 张承武[1] 姜桂林[1] 丁宁[1] 

机构地区：[1]山东省科学院能源研究所,山东济南250014

出　　处：《山东科学》2015年第2期31-38,共8页Shandong Science

基　　金：国家自然科学基金(51306107);山东省科技发展计划项目(2014GGX104008)

摘　　要：建立二维数学模型,对比研究了低雷诺数下(0~100)壁面加热对直径分别为2 cm、20μm及2μm的微圆柱漩涡脱落的影响规律。深入探讨了直径、壁面与流体温差对圆柱绕流中漩涡生长和脱落规律、尾流区速度、温度场及涡街参数分布等的影响规律及其原因,并基于计算结果拟合出了低雷诺数下斯特劳哈尔数(Sr)与雷诺数(Re)的定量关系式。研究发现当圆柱直径降至2μm时,与常规尺度圆柱相比微圆柱尾流区涡街的出现明显提前;而壁面加热减小了三者的差距,使三种不同直径圆柱背风区涡街出现的最低Re均降至40以下。微圆柱涡街的漩涡列距和间距之比h/l的值随着温差的增加而逐渐增大;相同温差下不同直径圆柱尾流区涡街h/l均随Re增加而减小,在相同Re下h/l值随圆柱直径的减小而明显增大。存在壁面加热时微圆柱绕流的Sr要高于无加热工况,两者之差最高可达20%左右。We established a two-dimensional numerical model and comparatively investigated the impact of heating wall on vortex shedding of micro-cylinders with different diameters of 2 cm, 20 μm and 2 μm for low Reynolds number （0 - 100）. We further addressed the cause and influence of diameter, wall and fluid temperature difference on vortex growth and shedding law, velocity at wake region, temperature field and distribution of vortex street parameters. We also fitted the quantitative relationship between Strouhal number and low Reynolds number. We found that vortices street of a micro- cylinder at wake region appeared much earlier than that of a convention-sized cylinder when its diameter reduced to 2 t^m. However, heating wall reduced the discrepancies among the cylinders with three different diameters and made the appearance of the lowest Re all less than 40 for the vortex street at leeward region. The ratio of row distance h to line distance ! of vortex street increased with the increase of temperature difference between the wall and the fluid, but the ratio of vortex street at wake region of different diameter cylinders decreased with the increase of Re for identical temperature difference. The ratio significantly increased with the decrease of the diameter of micro-cylinders for identical Re. Sr of a micro-cylinder with heating wall was greater than that without heating wall, the biggest discrepancy of 20% available.

关 键 词：微圆柱 漩涡脱落 壁面加热 数值模拟 

分 类 号：TK124[动力工程及工程热物理—工程热物理]