粘弹性流体基纳米流体导热系数和粘度的研究.pdf

国内图书分类号:TK39 学校代码:10213 国际图书分类号:621 密级:公开工学硕士学位论文粘弹性流体基纳米流体导热系数与粘度研究硕士研究生:周文武导师:李凤臣教授申请学位:工学硕士学科:动力工程及工程热物理所在单位:能源科学与工程学院答辩日期:2012年7月1 授予学位单位:哈尔滨工业大学 Classified Index: TK39 : 621 Dissertation for the Master Degree in Engineering On thermal conductivity and viscosity of viscoelastic-fluid-based nanofluids Candidate: Zhou Wenwu Supervisor: Prof. Li Fengchen Academic Degree Applied for: Master of Engineering Speciality: Power Engineering and Thermal Physics Affiliation: School of Energy Science And Engineering Date of Defence: July 1, 2012 Degree-Conferring-Institution:Harbin Institute of Technology 哈尔滨工业大学工学硕士学位论文-I- 摘要为了获得一种既具有纳米流体的高导热系数又具有粘弹性流体的湍流减阻性能的流体,本文首先以十六烷基三******化铵/水杨酸钠(CTAC/NaSal,其中NaSal提供抗衡离子)水溶液为基液、纳米Cu粒子和多壁碳纳米管(Ts)为纳米粒子配置了稳定的粘弹性流体基Cu/T纳米流体, 并对他们的分散性及悬浮稳定性进行了研究。其次,通过一系列的实验研究了粘弹性流体基纳米流体的导热系数和粘度与粒子体积分数、温度和基液浓度等因素的关系。导热系数实验测量结果表明: 与基液相比,粘弹性流体基纳米流体的导热系数有明显升高,且随着粒子体积分数与温度的升高而升高。然后,通过分析流变学研究结果发现粘弹性流体基纳米流体表现出明显的剪切稀变特性,且其剪切粘度随着粒子体积分数的增加而增加,随着溶液温度的增加而减少。最后,本文创新地运用微元分割法,分别提出了球形粒子与碳纳米管对应的纳米流体导热系数模型,并将纳米流体导热系数实验值与模型预测值进行对比,T纳米流体导热系数随温度/粒子体积分数变化的实验值吻合很好,最大误差为 %,同时利用建立的纳米流体导热系数模型简单地研究了纳米流体导热系数与各物性参数的关系,为进一步的理论研究提供基础。关键词:粘弹性流体基纳米流体;导热系数模型;粘度;多壁碳纳米管;铜纳米粒子哈尔滨工业大学工学硕士学位论文-II- Abstract For the sake of getting a novel heat transfer fluid with high heat transfer properties as well as turbulent drag reducing abilities, we have firstly prepared viscoelastic-fluid-based nanofluids (VFBN) using aqueous solution of cetyltrimethyl ammonium chloride/sodium salicylate (CTAC/NaSal, NaSal is as counterion.) as viscoelastic base fluid and carbon nanotubes (CNTs) as nanoparticles. Secondly, the thermal conductivity and shear viscosity of the prepared VFBN with variation of particle volume fraction, temperature and concentration of base fluid were exper