纳米流体强化对流换热的实验研究  

Experimental Study on Enhanced Convection Heat Transfer of Nanofluid

作　　者：李新芳[1] 朱冬生[2] 

机构地区：[1]中山火炬职业技术学院,中山528436 [2]华南理工大学传热强化与过程节能教育部重点实验室,广州510641

出　　处：《制冷学报》2009年第3期6-10,共5页Journal of Refrigeration

基　　金：教育部新世纪优秀人才支持计划(NCET-04-0826);中国博士后基金(20060400219)资助项目~~

摘　　要：建立了纳米流体对流换热系数的实验测试系统,利用实验系统测量了Cu-H_2O纳米流体的对流换热系数,探讨了纳米颗粒质量分数、Re数和轴向比对Cu-水纳米流体对流换热性能的影响。结果表明:Cu-水纳米流体的对流换热系数随纳米粒子质量分数的增大而增大,但其对流换热系数的增加明显低于导热系数的增加。随着雷诺数的增大,纳米流体的对流换热系数基本呈线性提高。纳米流体在实验管进口段的对流换热系数提高值明显高于流体在充分发展段的提高值。纳米流体的导热系数、粘度和纳米颗粒迁移是影响纳米流体对流换热系数的主要因素。The experimental system was built up to investigate convective heat transfer and flow characteristics of Cu-H2O nanofluid flowing in a tube. The effects of particle concentration, Reynolds number and axial distance on the convective heat transfer of Cu- H2O nanofluid were discussed. The experimental results show that the convection heat transfer of Cu-H2O nanofluid improves approximately with the mass fraction of the copper nanoparticle but its rise is lower than that of thermal conductivity. The convection heat transfer of Cu-H2O nanofluid rises approximately linearly with the Reynolds number. At a given Cu concentration, the heat transfer coefficient decreases with axial distance. The observed enhancement of the convective heat transfer could be attributed to the enhancement of thermal conductivity under static conditions, particle migration and re-arrangement, reduction of the boundary layer thickness, and delay in the boundary layer development.

关 键 词：工程热物理 纳米流体 对流换热 导热系数 颗粒迁移 

分 类 号：TK124[动力工程及工程热物理—工程热物理] TB612[动力工程及工程热物理—热能工程]