黏弹性流体基纳米流体流变学特性

黏弹性流体基纳米流体（viscoelastic fluid based nanofluid，VFBN）是一种具有湍流减阻和对流换热相对强化特性的新型换热工质，其湍流减阻机理与流变学特性关系密切。通过对以2.5×10^-3、5×10^-3、1×10^-2三种质量分数的十六烷基三甲基氯化铵/水杨酸钠水溶液为基液，粒子体积分数为0.1%、0.25%、0.5%、1.0%的铜纳米流体的剪切黏度、零剪切黏度以及松弛时间的测量，实验结果表明VFBN有明显的剪切稀变特性，同时纳米粒子的添加增大了基液的零剪切黏度，并导致基液黏弹性增强。以Giesekus本构模型为理论基础，利用实验参数得到了描述VFBN剪切黏度的实验关联式。

Rheological properties of vicoelastic fluid based nanofluid

Viscoelastic fluid based nanofluid (VFBN) takes the advantages of turbulent drag reduction and convective heat transfer enhancement. Rheological properties of viscoelastic fluid are related with the mechanism of turbulent drag reduction. In order to get the rheology properties of VFBN, the VFBN with aqueous solution of cetyltrimethylammonium chloride/sodium salicylate as viscoelastic base fluid and copper nanoparticles as suspended nanoparticles was prepared. The mass fraction of viscoelastic fluids are 2.5×10^-3, 5×10^-3and 1×10^-2, and the corresponding volume fraction of copper (spherical) nanoparticles are 0.1%, 0.25%, 0.5% and 1.0%, respectively. Experimental results indicate that VFBN shows obvious shear-thinning characteristics, the suspended nanoparticles can increase the zero-shear viscosity and enhance the viscoelasticity of base fluid. Based on the Giesekus constitutive equation, fitted correlations for the measured shear viscosity of VFBN have been obtained by modifying some experimental parameters.