拟塑性非牛顿纳米薄液膜流动传热传质过程研究

Nanofluid and nanotechnology is a hot topic in today’s world of scientific research subject. Based on the view of non-Newtonian fluid dynamics, nonlinear differential equation and heat mass transfer, the flow heat and mass transfer characteristics of pseudo-plastic non-Newtonian thin nanoliquid film are considered in this project. Three types of mechanism of thin liquid film will be established, i.e. thin liquid film over a stretching surface, thin liquid film over a inclined heated plate and free falling liquid film over a vertical wall. The non-Fourier heat transfer (i.e. Pop’s heat transfer and Zheng and Zhang’s heat transfer), non-Fick mass transfer (i.e. Philip’s N-diffusion and Pascal’s hybrid diffusion), and three kinds of nanofluid model (i.e. the traditional modified coefficient model and Buongiorno’s model) are taken into account. The theory of similarity transformation and nonlinear differential equation are applied to solve the related nonlinear problem in this project. And the numerical simulation and experimental research methods are used to verify the validity of the theoretical results. The flow heat and mass transfer characteristics of pseudo-plastic non-Newtonian thin nanoliquid film will be analyzed and discussed in detail. The study of this project will be reveal some essences of the nonlinear behavior and provide a new idea or method for basic research and engineering practice.

纳米流体与纳米科技是当今世界科学研究的热点课题。本项目基于非牛顿流体动力学、非线性微分方程和传热传质学的观点，建立延伸表面薄液膜、沿坡面加热薄液膜以及垂直自由降膜的数理模型，开展拟塑性非牛顿纳米薄液膜流动传热传质特性的研究。传热过程重点考虑非Fourier传热，即Ioan Pop提出的速度幂律传热模型与郑连存、张欣欣提出的温度幂律传热模型；传质过程重点考虑非Fick扩散过程，即Philip提出的N-幂律扩散模型与Pascal提出的浓度与浓度梯度混合模型；纳米流体重点考虑传统的系数修正模型与Buongiorno提出的污染物模型。充分运用近代数学中相似变换方法与非线性微分方程理论进行求解，同时结合数值模拟与实验手段进行印证。分析并探讨拟塑性非牛顿纳米薄液膜流动传热传质过程的机理，深刻理解输运的本质，揭示其内在规律，以期为相关科学研究和工程应用提供依据、思路和方法。

项目走多学科交叉的技术路线，基于近代数学中相似变换理论与微分方程求解方法，结合非牛顿流体力学、非线性微分方程、传热传质学、热能工程以及纳米材料科学等的观点，研究了拟塑性非牛顿薄液膜的流动传热传质特性。传热过程考虑了三种不同的形式(传质过程与传热过程类似)：一是经典的牛顿流体下傅里叶导热过程，二是针对幂律非牛顿流体Ioan Pop提出的速度梯度幂律形式，三是针对幂律非牛顿流体郑连存教授与张欣欣教授提出的温度梯度幂律形式。纳米流体考虑了传统的系数修正模型与Buongiorno提出的污染物模型(两相流模型)。充分运用近代数学中相似变换方法与非线性微分方程理论进行求解，结合连续有限元Freefem++等进行数值离散、计算与模拟，分析重要的一些物理参数对流动传热传质过程的影响。在相关交叉学科主流的SCI/EI期刊如International Journal of Heat and Mass Transfer、Engineering Applications of Computational Fluid Mechanics等发表学术论文5篇(项目负责人第一作者或通讯作者，第一标注)。