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Particle engineering for the formulation of smart functional fluids - Novel synthesis, processing and comparative analysis of magnetic nanoparticles and fluids.

机译：用于智能功能流体配方的粒子工程-磁性纳米粒子和流体的新颖合成，加工和比较分析。

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摘要

The goal of this project is the development of iron nanofluids for magnetic and thermal applications. The specific contribution of this project to the advancement of science is the detailed study of scale-up procedures for the preparation of iron nanofluids using three different methodologies. Emphasis is placed on engineering the particles such that they meet certain morphological characteristics for microfluidic device development. A two-step approach is explored to formulate the nanofluids, starting with nanopowder development followed by the dispersion of synthesized nanopowders in a carrier fluid. The processing of nanopowders is carried out by optimizing the microemulsion, coprecipitation, and polyol synthesis processes. To study the effect of different processing parameters on the structure, phase, particle, and agglomerate sizes of the powders, the precursor concentrations, pH, temperature, processing time, stabilizers, surfactants, and polymers are varied. In-situ growth mechanisms of crystalline iron and iron oxide nanoparticles are discussed. The results show crystalline phases of metallic and oxide phases of iron with varying particle sizes (5-200 nm) and morphologies obtained under a variety of conditions. After nanopowder synthesis, the sonochemical technique is used to disperse powders in a base fluid to develop magnetorheological fluids (nMRF) and thermal fluids. The yield strength, flow, and thermal conductivity characteristics are measured for the developed fluids with varying solids loadings. The results show an enhancement of ∼20% in thermal conductivity for iron nanofluids over base fluids without the application of an external field. The nMRF's show maximum yield strength of ∼4 kPa with the ability to flow through microchannels.
机译：该项目的目标是开发用于磁性和热学应用的铁纳米流体。该项目对科学发展的特殊贡献是使用三种不同方法对制备铁纳米流体的放大程序的详细研究。重点放在对颗粒进行工程设计，以使它们满足微流体设备开发的某些形态特征。探索了一种两步法来配制纳米流体，首先是开发纳米粉，然后是将合成的纳米粉分散在载液中。纳米粉末的加工是通过优化微乳液，共沉淀和多元醇合成工艺来进行的。为了研究不同加工参数对粉末的结构，相，颗粒和附聚物尺寸的影响，改变了前体浓度，pH，温度，加工时间，稳定剂，表面活性剂和聚合物。讨论了结晶铁和氧化铁纳米粒子的原位生长机理。结果显示出具有变化的粒径（5-20​​0 nm）的铁的金属相和氧化物相的结晶相，以及在各种条件下获得的形态。纳米粉末合成后，使用声波化学技术将粉末分散在基础流体中，以开发磁流变流体（nMRF）和热流体。测量了具有变化的固体载荷的已开发流体的屈服强度，流量和导热系数特性。结果表明，在不使用外部电场的情况下，铁纳米流体的导热系数比基础流体提高了约20％。 nMRF的最大屈服强度约为4 kPa，具有流经微通道的能力。

著录项

  • 作者

    Sinha, Kaustav.;

  • 作者单位

    University of Nevada, Reno.;

  • 授予单位 University of Nevada, Reno.;
  • 学科 Engineering Chemical.;Engineering Materials Science.;Engineering Mechanical.
  • 学位 Ph.D.
  • 年度 2008
  • 页码 212 p.
  • 总页数 212
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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