摘要
采用数值模拟的方法,研究与等直径段有不同夹角的水滴型凹穴微通道的流动与传热特性,并通过强化传热因子(h)和熵产增大数(N_(s,a))对其综合性能进行了评价。结果表明:带有凹穴的微通道的进出口压降沿着流动方向呈锯齿形下降,与矩形微通道相比,水滴型凹穴的存在对压降的影响较小。小Re时,水滴型凹穴微通道的传热效果增加较少甚至小于矩形直通道,而当Re>300时,随着水滴型凹穴出口切线与等直径段夹角的减小,微通道热沉的传热性能逐渐增大。熵产分析表明,由传热引起的不可逆损失随着雷诺数的增大而增大,而由流动摩擦引起的不可逆损失随之减小,而且传热熵产在总熵产中占主要部分。水滴型凹穴微通道的不可逆损失均小于矩形直通道,而且与等直径段夹角越小的凹穴微通道其不可逆损失越小。
A numerical investigation is performed to study the flow and heat transfer characteristics in a microchannel with droplet reentrant cavities, which have different angles with equal diameter section. The thermal enhancement factor （r/） and augmentation entropy generation number （Ns,a） are used to evaluate the comprehensive performance of the microchannel. The numerical results indicate that the pressure drop of microchannel with droplet reentrant cavities reduced zigzag along the flow direction. Compared with the rectangular microchannel, the droplet reentrant cavities have less effect on the pressure drop. When Re is small, the effect of droplet reentrant cavities on heat transfer increases little and even less than rectangular. However, when Re〉300, as the angle between export tangent of reentrant cavity and equal diameter section decreases, the heat transfer performance gradually increases. The analysis of entropy generation show that the irreversible loss caused by heat transfer increases with the Reynolds number, but the irreversible loss caused by flow friction decreases, and heat transfer entropy generation is the major component of the total entropy generation. The irreversible loss of microchannel with droplet reentrant cavities is smaller than the rectangular channel and the smaller of angle with equal diameter section, the less of the irreversible loss,
作者
贾玉婷
夏国栋
马丹丹
李艺凡
宗露香
JIAYuting XIA Guodong MA Dandan LI Yifan ZONG Luxiang(College of Environmental and Energy Engineering, Beijing University of Technology, Beijing 100124)
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2017年第4期141-148,共8页
Journal of Mechanical Engineering
基金
国家自然科学基金(51576005)
河北省自然科学基金-青年基金(E2016502048)资助项目
关键词
微通道
水滴型凹穴
传热
数值模拟
熵产分析
microchannel： droplet reentrant cavities： heat transfer
numerical simulation： entropy generation analysis
