纳米流体液滴碰撞壁面铺展动力学特性及碳纳米管分布取向机制的研究

项目名称： 纳米流体液滴碰撞壁面铺展动力学特性及碳纳米管分布取向机制的研究

项目编号： No.51506078

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 能源与动力工程

项目作者： 刘海龙

作者单位： 江苏大学

项目金额： 21万元

中文摘要： 纳米流体是一类新型高导热非牛顿流体。纳米流体液滴碰撞固体壁面的铺展特性及液滴内碳纳米管的分布取向，是影响基于液滴沉积实现高效传热传质过程的关键因素。然而由于纳米流体的非牛顿流变特性及液滴内微流动与碳纳米管的耦合作用，目前对纳米流体液滴碰撞固壁铺展的动力学行为及碳纳米管分布取向缺乏足够的认识。本项目拟通过高速摄影的手段，获得纳米流体液滴碰撞壁面的铺展沉积形态及重要动力学特性参数的演变规律。通过液滴光固化技术及电镜扫描观测，结合统计学方法获得碳纳米管在液滴内的分布取向特征。基于短纤维悬浮体系理论建立碳纳米管在流场内取向预测模型及纳米流体流变学本构关系。结合数值模拟,揭示非牛顿流变特性及初始碰撞条件对液滴动力学特性的影响，认识并阐明纳米流体液滴内微流动流场与碳纳米管取向分布的相互作用机制。相关研究成果将为基于纳米流体液滴沉积的增益传热冷却技术及高导热微型电子器件制造提供理论依据和具体指导。

中文关键词： 纳米流体；流变行为；液滴铺展；动力行为；碳纳米管取向

英文摘要： The nanofluid is a class of fluids with high thermal conductivity and non-Newtonian flow behavior. The orientation of CNTs and the spreading characteristics of a nanofluid droplet impinging on the solid surface are key factors to efficient heat and mass transfer in related processes based on the deposition of droplets. However, the dynamic behaviors and characteristics of the nanofluid droplet haven’t been fully understood since the presence of the non-Newtonian fluid behavior and the interaction between the microstructure of CNTs and micro-flow field in the droplet which complicates the spreading process. In this project, we intend to obtain the evolution of droplet morphology and critical parameters of dynamics parameters during the droplet spreading by means of high-speed photography. By utilizing the light-curing technology and SEM scan, we will observe the morphology of CNTs in the droplet and analysis their distribution and orientation by probability statistics method. By analogizing the short fibers in suspension, we plan to derive a model to predict the orientation of CNTs in flow field and a constitutive equation to describe the rheological behavior of the nanofluid. With the numerical simulation, we intend to reveal the effects of non-Newtonian rheological properties and the initial impact conditions on the dynamic characteristics of the spreading. From a comprehensive analysis, we will elucidate the mechanism of coupling effect between the dynamic behaviors of micro-flow field and orientation of CNTs in the droplet. The results of this project will provide theoretical basis and specific guidance on designing enhanced heat transfer and cooling technology, as well as manufacturing micro-devices with high thermal-conductivity, which are based on the deposition of nanofluid droplet.

英文关键词： nanofluid;rheological behavior;droplet spreading;dynamic behavior;CNT orientation