高宽比对竖壁冷却离散加热的二维空腔内自然对流的影响

The Effect of Aspect Ratio on Natural Convection in a Cavity with Discrete Heaters and a Vertical Heat Sink

采用SIMPLE算法数值分析了高宽比对一侧竖壁等温冷却、另一侧竖壁均匀分布5个离散热源的空腔内高Pr数流体自然对流流动和传热的影响。发现H/W=12.22时出现的多个二次流强化了传热,其整体传热效果最好;H/W减小时由于二次流的减弱和消失,传热急剧下降,并在H/W=7.35时达最小值;H/W继续减小时,由于对流的展开和加剧使传热得到某种程度的增强,在H/W=3.67时达到稳定,在这之后H/W的减小对传热不再产生显著的影响。另外,根据数值计算的结果还整理出了包含高宽比影响的综合关系式。

SIMPLE method is used to study the influence of aspect ratio on the natural convection in an enclosure with five discrete heat sources on a vertical wall and an isothermal heat sink on another vertical wall. The range of aspect ratio is from 3. 0 to 12. 22. At high aspect ratio, multiple secondary flow cells can be found,which enhance heat transfer strongly and cause the highest heat transfer coefficient based on cooling area Nuc. With the decrease of aspect ratio,secondary flow cells become weaker gradually and finally reach the lowest Nuc at H/W = 7. 35. If H/W continues to decrease,natural convection is gradually developed,and heat transfer is improved. At H/W = 3. 67,Nuc becomes stable. Then the decrease of aspect ratio will not affect heat transfer. Besides, A heat transfer correlation including the influence of aspect ratio is .also provided.