南通大学学报（自然科学版）2017，Vol.16Issue(4)：22-27,6.
层流下不同扩张比对后向台阶流动和传热特性的影响
The Effects of Expansion Ratios in Laminar on Flow and Heat Transfer Characteristics in Backward-Facing Steps
摘要
Abstract
A three-dimensional steady numerical model was established to study the effects of expansion ratio on flow and heat transfer characteristics over a backward-facing step at low Reynolds number range (50 ≤ Re ≤ 250).Expansion ratio (ER) treated in the present study was 1.5,2.0,and 3.0 under a step aspect ratio of 16.0.The flow and thermal fields of the backward-facing step flow are simulated by use of Fluent.The present numerical results for ER =2.0 are in a good agreement with the previous experimental ones.It is found that the line connecting the reattachment points on the bottom is parabolic.When Reynolds number is constant,the scale of two symmetric vortices on the up wall of the backward-facing step becomes larger with the increase of the expansion ratio.In addition,as the increase of ER,the peak Nu on the center line of bottom is increasing and the position of the reattachment point is closer to the step.Compared with two-dimensional simulation,the peak Nu on the center line of the three-dimensional bottom is lower than that on the two-dimensional bottom at the same expansion ratio.关键词
后向台阶/稳定流动/传热/扩张比Key words
backward-facing step (BFS)/steady flow/heat transfer/expansion ratio分类
能源科技引用本文复制引用
沈洁惠,徐加辉,稲岡恭二,喜冠南..层流下不同扩张比对后向台阶流动和传热特性的影响[J].南通大学学报（自然科学版）,2017,16(4):22-27,6.基金项目
国家自然科学基金项目(51476080) （51476080）
