化工学报

• •    

微通道内纳米流体传热流动特性

刘萍(), 邱雨生, 李世婧, 孙瑞奇, 申晨   

  1. 安徽理工大学机电工程学院,安徽 淮南 232001
  • 收稿日期:2024-05-30 修回日期:2024-08-03 出版日期:2024-09-12
  • 通讯作者: 刘萍
  • 作者简介:刘萍(1978—),女,博士,教授,pingliu@mail.ustc.edu.cn
  • 基金资助:
    安徽省重点研究与开发计划项目(2022a05020030)

Heat transfer and flow characteristics of nanofluids in microchannels

Ping LIU(), Yusheng QIU, Shijing LI, Ruiqi SUN, Chen SHEN   

  1. School of Mechatronics Engineering, Anhui University of Science and Technology, Huainan 232001, Anhui, China
  • Received:2024-05-30 Revised:2024-08-03 Online:2024-09-12
  • Contact: Ping LIU

摘要:

为提高微通道散热器的传热效率,需要对微通道进行结构优化设计。以热阻Rt和泵功Pp为目标函数,在Re=100的条件下,采用多目标遗传算法对文丘里管微通道的结构参数,如通道深度,收缩角度,喉颈宽度和扩散角度进行优化,通过遗传迭代计算得到Pareto优化解集,利用k-means聚类法对优化解集进行比较分析,通过强化传热因子η对各聚类点综合性能进行评价,得到最优的微通道结构。采用数值模拟方法,研究优化后的微通道结构的流动与传热特性。结果表明:当去离子水中加入纳米颗粒后微通道内的压降具有小幅度上升,但其流动阻力在相同Reynolds数的条件下并没有发生较大的变化。在文丘里管微通道喉部位置会产生喉部效应,强化纳米颗粒与微通道中流动工质的融合。熵产分析表明,传热熵随着Reynolds数的增大而减小,摩擦熵随着Reynolds数的增大而增大,不过总熵值中主要是传热熵占据主导地位。纳米流体随着体积分数的增加不可逆损失均小于去离子水。

关键词: 遗传优化, 优化设计, 微通道, 纳米流体, 强化传热, 数值模拟

Abstract:

In order to improve the heat transfer efficiency of microchannel heat sink, it is necessary to optimize the structure of microchannel. Taking thermal resistance Rt and pump power Pp as the objective function, under the condition of Re = 100, the multi-objective genetic algorithm is used to optimize the structural parameters of the Venturi microchannel, such as channel depth, contraction angle, throat width and diffusion angle. The Pareto optimal solution set is obtained by genetic iteration calculation, and the optimal solution set is compared and analyzed by k-means clustering method. The comprehensive performance of each clustering point is evaluated by the enhanced heat transfer factor η, and the optimal microchannel structure is obtained. The flow and heat transfer characteristics of the optimized microchannel structure were studied by numerical simulation. The results show that the pressure drop in the microchannel increases slightly when nanoparticles are added to deionized water, but the flow resistance does not change greatly under the same Reynolds number. The throat effect will be generated at the throat position of the venturi microchannel to strengthen the fusion of nanoparticles and the flowing working fluid in the microchannel. The entropy generation analysis shows that the heat transfer entropy decreases with the increase of Reynolds number, and the friction entropy increases with the increase of Reynolds number, but the total entropy is mainly dominated by heat transfer entropy. With the increase of volume fraction, the irreversible loss of nanofluids is less than that of deionized water.

Key words: genetic algorithm, optimal design, microchannel, nanofluid, heat transfer enhancement, numerical analysis

中图分类号: