悬浮等离子体喷涂过程中微纳米颗粒撞击基板的动力学模拟（英文）

发布时间：2017-12-28 09:35

本文关键词：悬浮等离子体喷涂过程中微纳米颗粒撞击基板的动力学模拟（英文）　出处：《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》2016年09期 　论文类型：期刊论文

【摘要】：目的:研究微纳米颗粒在流场中的运动和传热特性,确定颗粒绕流的临界尺寸以及微纳米颗粒合适的喷涂距离。创新点:1.建立微纳米颗粒的受力和运动模型;2.推导颗粒粒径和斯托克斯数的关系,确定颗粒绕流的临界尺寸;3.确定适于微纳米颗粒的喷涂距离。方法:1.通过颗粒运动和传热的三维模型,模拟颗粒在等离子体流场中的运动和传热过程;2.对流场采用欧拉法进行求解,对颗粒采用拉格朗日法进行求解;3.动态追踪颗粒的轨迹和空间分布,从而得到颗粒的速度、温度和空间分布。结论:1.布朗力会影响纳米颗粒的分布;现有模型可以很好地模拟微纳米颗粒的行为。2.可以用斯托克斯数和粒径表征微纳米颗粒绕流的临界尺寸;当前工况下,临界粒径约为800 nm。3.基板会影响流场结构和颗粒的空间分布;在当前研究中,得出有利于纳米颗粒沉积的喷涂距离约为50 mm;对微米颗粒来说,喷涂距离应适当增大。4.微纳米颗粒的空间分布呈现不同的特点;纳米颗粒的分布区间更大,布朗力对纳米颗粒的作用比对微米颗粒更为显著。5.微纳米颗粒的运动和传热过程呈现不同的特点;纳米颗粒的惯性和热容小,因此它们的速度和温度变化更迅速。
[Abstract]:Objective: To study the motion and heat transfer characteristics of micro nano particles in the flow field, determine the critical size of the flow around the particles and the suitable spray distance of the micro nanoparticles. Innovations: 1.. Establish the force and motion models of micro and nano particles; 2., deduce the relationship between particle size and Stokes number, determine the critical size of particle flow, and 3., determine the spray distance suitable for micro and nano particles. Methods: 1. through the three-dimensional model of particle movement and heat transfer, flow and heat transfer simulation of particles in the plasma flow in the flow field; 2. using Euler solution to solve the particle by Lagrange method; 3. dynamic tracking distribution of particle trajectories and obtained from space, particle velocity, temperature distribution and space. Conclusion: 1. Brown force will affect the distribution of nanoparticles, and the existing models can well simulate the behavior of micronanoparticles. 2. the critical size of the flow around micronanoparticles can be characterized by Stokes number and particle size, and the critical particle size is about 800 nm under the current condition. The 3. substrate will affect the flow field structure and the spatial distribution of particles. In the current research, it is concluded that the spray distance conducive to nanoparticle deposition is about 50 mm. For micron particles, the spray distance should be increased appropriately. 4., the spatial distribution of micro and nano particles has different characteristics. The distribution range of nanoparticles is larger, and the effect of Brown force on nanoparticles is more significant than that of micron particles. The motion and heat transfer process of 5. micro nanoparticles show different characteristics; the inertia and heat capacity of the nanoparticles are small, so their speed and temperature change more rapidly.
【作者单位】： State
【基金】：supported by the National Natural Science Foundation of China(Nos.11072216 and 11472245) the Fundamental Research Funds for the Central Universities(No.2012FZA4027),China
【分类号】：TB383.1;O357.5
【正文快照】： 1 Introduction Suspension plasma spray(SPS)is a novel spray technology(Fauchais,2004).In the SPS process,the nano-sized particles in the feedstock usually have diameters between 100 nm and 1μm.These particles are dispersed in suspension and then inject

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