Abstract:

It is a thorny problem for micro-particle deposition based on gas-solid flow. Particle deposition is a common physical phenomenon but with more negative impact, such as the wear of turbine blades caused by sand particles, scale corrosion caused by fly ash particles on boiler heat exchange surface and so on. Although the continuous optimization of soot blowing scheme has greatly reduced the negative impact of fly ash deposition, there are still some uncontrollable problems. Therefore, it is of great significance to summarize and analyze the law of particle adhesion behavior to suppress particle deposition in engineering. Based on the main background of boiler fly ash deposition, this paper expounded the mechanism and characteristics of particle adhesion dominated by inertial impact, reviewed the research work on critical deposition criteria in recent years, focused on the analysis of the influence of deposition factors on the criteria of particle adhesion/rebound, and summarized the main criteria of particle detachment. By comparing the problems and connections of relevant criteria horizontally, the research status and existing problems of particle adhesion criteria was explained, which provided technical and theoretical support for the effective suppression of boiler deposition and the promotion of particle detachment theory.

Key words: micro-particles, deposition model, critical capture velocity, restitution coefficient, critical shear velocity

摘要：

基于气固两相流动的微颗粒沉积一直是一个棘手的问题，作为一种常见的物理现象，带来的影响更多是负面的，如砂粒导致涡轮叶片的磨损，飞灰颗粒引起锅炉换热面结垢腐蚀等一系列问题。尽管吹灰方案的不断优化已经很大程度减少了飞灰沉积带来的负面影响，但仍有一些不可控或意外的问题存在。因此，归纳分析颗粒黏附行为规律对工程颗粒沉积的抑制具有重要意义。本文以锅炉飞灰沉积为主要背景，阐述了以惯性撞击为主导机制的颗粒黏附机理与特性，回顾了近年来对临界沉积标准的研究工作，重点剖析了沉积因素对颗粒黏附/反弹判据标准的影响，总结了颗粒剥离的主要判断准则，通过横向对比相关判据存在的问题与联系，说明了颗粒黏附判据标准的研究现状与存在的问题，为实现锅炉沉积的有效抑制及颗粒剥离理论的推广提供技术理论支撑。

关键词: 微米颗粒, 沉积模型, 临界捕集速度, 恢复系数, 临界剪切速度