| 气固两相湍流场纳米颗粒演变特性综述 |
| |
| 引用本文： | 石瑞芳,林建忠. 气固两相湍流场纳米颗粒演变特性综述[J]. 航空学报, 2021, 42(12): 625825-625825. DOI: 10.7527/S1000-6893.2021.25825 |
| |
| 作者姓名： | 石瑞芳 林建忠 |
| |
| 作者单位： | 浙江大学 航空航天学院 流体工程研究所,杭州 310027 |
| |
| 基金项目： | 国家自然科学基金重大研究计划（91852102） |
| |
| 摘 要： | 含纳米颗粒的气固两相湍流场在包括航空等众多领域中很常见，以单体、聚集体和团聚体不同形式存在的纳米颗粒在流场中经过生成、对流、扩散、凝并、破碎等过程，其数密度、尺度、尺度分散度等将发生变化。本文就以上相关研究状况进行了回顾，说明颗粒生成是气相化学反应产生的可冷凝蒸汽物质因表面冷却、绝热膨胀或混合、湍流混合或化学过程产生的过饱和所导致；导致颗粒凝并的原因包括布朗运动、湍流剪切、速度梯度、差异沉降；颗粒的凝并取决于颗粒的尺度和流场的特性，并受初始颗粒分布及湍流扩散控制；湍流场对颗粒凝并的影响除了湍流强度的因素外，还体现在由湍流脉动所引发的颗粒数密度的脉动；颗粒凝并后形成尺度较大的团聚体容易在流场剪切和其他因素作用下发生破碎；剪切破碎是导致颗粒破碎的主要因素，有效破碎系数取决于剪切率和颗粒的体积分数；颗粒的沉降取决于颗粒尺度、形状和流体性质等因素；导致颗粒沉降的因素有重力、扩散、惯性撞击、电场和热迁移等；当存在温度梯度时，热泳力对颗粒沉降也起到重要作用。本文最后提出了有待进一步研究的若干问题。
|
| 关 键 词： | 气固两相湍流场 纳米颗粒 成核 凝并 破碎 沉降 |
| 收稿时间： | 2021-05-17 |
| 修稿时间： | 2021-06-28 |
A review on evolution characteristics of nanoparticles in gas-solid two-phase turbulent flow field |
| |
| SHI Ruifang,LIN Jianzhong. A review on evolution characteristics of nanoparticles in gas-solid two-phase turbulent flow field[J]. Acta Aeronautica et Astronautica Sinica, 2021, 42(12): 625825-625825. DOI: 10.7527/S1000-6893.2021.25825 |
| |
| Authors: | SHI Ruifang LIN Jianzhong |
| |
| Affiliation: | Institute of Fluid Engineering, School of Aeronautics and Astronautics, Zhejiang University, Hangzhou 310027, China |
| |
| Abstract: | The gas-solid two-phase turbulent flow with nanoparticles is very common in many fields including aviation. In the flow field, the nanoparticles, in the form of monomer and aggregate, undergo the processes of generation, convection, diffusion, coagulation and breakage, while the number density, scale and scale dispersion of particles will change. In this paper, we review the above research and draw the following main conclusions:Particle formation is caused by surface cooling, adiabatic expansion or mixing, turbulent mixing or supersaturation of condensable vapor produced by gas-phase chemical reaction; the causes of particle coagulation include Brownian motion, turbulent shear, velocity gradient and differential settlement; particle coagulation depends on particle size and flow field characteristics, and is controlled by initial particle distribution and turbulent diffusion; the influence of turbulence field on particle coagulation is not only the turbulence intensity, but also the fluctuation of particle number density caused by turbulence fluctuation; the agglomerates with large size formed after particle coagulation are easy to be broken under the action of flow shear and other factors; shear fracture is the main factor leading to particle breakage; and the effective breakage coefficient depends on the shear rate and the volume fraction of particles; the deposition of particles depends on the particle size, shape and fluid properties of particles; gravity, diffusion, inertial impact, electric field and heat transfer are the main factors leading to particle deposition; when there is a temperature gradient, the thermophoretic force also plays an important role in particle deposition. Finally, some problems are put forward for further studies. |
| |
| Keywords: | gas-solid two-phase turbulent flow field nanoparticles nucleation coagulation breakage deposition |
| 本文献已被 万方数据 等数据库收录！ |
| 点击此处可从《航空学报》浏览原始摘要信息 |
|
点击此处可从《航空学报》下载全文 |
|
