| 摘要: |
| 本文在微通道中4种常规肋片基础上，通过在肋片上复合凹穴结构，提出4种对应的凹穴复合肋片。通过数值模拟方法，研究了常规肋片和对应凹穴复合肋片对微通道流动和换热特性的影响，并分析了凹穴对流动和换热性能的影响机制，最后采用性能评价准则PEC对比其综合性能。结果表明：凹穴结构复合于肋片后，减小了肋片最大宽度，有利于减小肋片下游分离区，且凹穴处流体在主流带动下会形成回流区，进而减少了肋片与主流间的摩擦总阻力，相比于常规肋片可显著降低流动压降，其中Re=800时压降最大可减少52.03%。但凹穴结构也会降低肋片对主流的扰动作用，削弱了肋片附近流体和主流间对流和掺混，造成微通道强化换热效果恶化。凹穴结构对流动和换热特性的影响与肋片形状有关。以PEC为基准评价综合性能时，凹穴结构削弱换热的缺陷造成综合性能下降。 |
| 关键词: 微通道换热器 热流密度 表面传热系数 肋片 凹穴 |
| DOI： |
| Received:April 15, 2023Revised:May 31, 2023 |
| 基金项目:国家自然科学基金(52206127)资助项目 |
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| Investigation of Flow and Heat Transfer Characteristics for Fins Compound with Cavities in Microchannels |
|
Huang Binghuan1, Mi Chuang1, Li Kui2,3, Gong Liang1
|
| (1.College of New Energy, China University of Petroleum (East China);2.School of Computer Science, Northwestern Polytechnical University;3.Xi'an Institute of Microelectronics Technology) |
| Abstract: |
| In this study, based on fins of four conventional shapes that are applied in microchannels, four novel fins are proposed using compound fins with cavities. Numerical simulations were conducted to investigate the flow and heat transfer characteristics of microchannels with conventional fins and those integrating fins with cavities. The mechanism by which the cavities influence the flow and heat transfer performance was analyzed, and performance evaluation criteria (PEC) was adopted as a criterion to compare the overall performance. The results showed that as the fin was compounded with cavities, the width of the fin decreased; thus, the separation zone downstream of the fin was reduced. In addition, the main flow induced a cyclic flow in the cavities. The velocity gradient at the liquid-liquid interface between the main flow and the cyclic flow was lower than that at the liquid-solid interface between the main flow and the fin surface, resulting in lower flow friction. Therefore, the pressure drop of the flow associated with fins with cavities was lower than that for conventional fins. However, the cavities reduced the disturbance of the main flow, leading to a deteriorated heat transfer enhancement performance. The influence of the cavities on the flow and heat transfer depended on the fin shape. Compared with conventional fins, the overall performance of fins compounded with cavities was reduced owing to heat-transfer deterioration. |
| Key words: microchannel heat exchanger heat flux surface coefficient of heat transfer fin cavity |
