基于丙三醇的纳米流体多相流动与传热特性及微观结构调控机理

Base solvents of traditional nanofluids are not able to be used under extreme climatic conditions or special equipment requirements due to their relatively narrow liquid ranges. Therefore, there is an urgent need to develop alternatives. In this project, we plan to use glycerol, which is recognized as a by-product of biodiesel, as a base solvent of nanofluid and study its multiphase flow and heat transfer characteristics. From the viewpoint of high viscosity of glycerol, interaction between glycerol molecules and nanoparticles, microscopic molecular structure of glycerol and nanofiller will be studied by chemical methodologies with the aim to reduce the viscosity of glycerol nanofluids on the premise of keeping the wide liquid range. Research contents of this project can be briefly divided as follows: (1) nanofluids preparation based on hydrogen bond recombination and its thermophysical properties study; (2) thermal properties and microstructure control mechanism study of graphene catalyzed and enhanced glycerol ketal/aldehyde nanofluid; (3) heat transfer characteristics and drag reduction mechanism study towards glycerol nanofluid multiphase flow in microchannels. The aim of this project is listed as follows: (1) preparation of glycerol based nanofluids which possessing wide liquid range, low viscosity, high thermal conductivity and stable characteristics; (2) unveil the regulation between thermal physical property and interaction existed between base fluid and nanoparticle in molecular level; (3) reveal the microchannel flow and heat transfer property of glycerol based nanofluid under a complicated working condition.

传统纳米流体基液受限于较窄的液程而无法适用于极端的气候条件或特殊设备下的热管理需求，因此迫切需要开发新的替代物。本项目拟采用生物柴油工业生产过程中的副产物丙三醇为纳米流体基液，针对丙三醇高粘度、高阻力的缺点，拟通过丙三醇分子微观结构调控，在纳米流体宽液程的前提下，减小丙三醇纳米流体粘度。主要研究内容包括：(1)基于丙三醇氢键键能重组的纳米流体制备及其热物性变化规律研究；(2)石墨烯催化丙三醇缩酮/醛纳米流体热性能及微观结构调控机制研究；(3)微小通道内改性丙三醇纳米流体多相流动传热特性及减阻机理研究。拟实现的研究目标包括：(1)制备以丙三醇为起始物的宽液程、低粘度、高导热系数和强稳定性的纳米流体；(2)从分子角度揭示丙三醇分子与纳米材料之间的化学作用力对纳米流体热物性的影响规律；(3)揭示复杂工况条件基于丙三醇的纳米流体于微小通道中的流动传热规律。

传统换热工质受限于导热系数较低，无法满足高性能换热需求。纳米流体是指以一定的方式和比例在液体中添加金属或金属氧化物的纳米颗粒后形成的一种均匀稳定且导热系数高的新型换热工质。基液作为承载纳米颗粒的溶液，决定了纳米流体的基本性质。传统纳米流体基液受限于较窄的液程而无法适用于极端的气候条件或特殊设备下的热管理需求，因此迫切需要开发新的替代物。本项目拟采用生物柴油工业生产过程中的副产物丙三醇为纳米流体基液，针对丙三醇高粘度、高阻力的缺点，拟通过丙三醇分子微观结构调控，在纳米流体宽液程的前提下，减小丙三醇纳米流体粘度。主要研究内容包括：(1)基于丙三醇氢键键能重组的纳米流体制备及其热物性变化规律研究；(2)石墨烯催化丙三醇缩酮/醛纳米流体热性能及微观结构调控机制研究；(3)微小通道内改性丙三醇纳米流体多相流动传热特性及减阻机理研究。得到如下重要结果（1）明晰了丙三醇和其他氢键受体的配比以及工艺条件对其热物性参数的影响规律及内在机理；（2）得到了氢键受体及醛酮结构对纳米流体稳定性及热物性的影响规律，以及纳米粒子表面结构和形貌对纳米流体稳定性及热物性的影响规律。（3）对丙三醇低温共熔溶剂纳米流体在微通道内部的热质传递和流动阻力的进行量纲分析，构建无量纲传热关联式和摩擦因子无量纲模型；（4）建立具有不同结构和尺寸的微通道流动传热数值模型，研究微通道尺寸结构对丙三醇基纳米流体流动传热特性的影响规律，并通过对微通道尺寸结构进行优化分析传热流动规律。基于本项目，以第一/通讯并标注本项目发表高水平学术论文28篇，其中SCI期刊论文22篇，中文EI论文6篇；授权发明专利7件。