Effects of thermophoresis on Brownian coagulation of spherical particles over the entire particle size regime  

作　　者：Kaiyuan Wang Pei Wang Suyuan Yu 

机构地区：[1]Institute of Applied Physics and Computational Mathematics,Bejing 100094.China [2]Center forCombustionEergy.Key Laboratory for Thermal Science and Power Engineering of Ministry of Education,Department of Energyand PowerEngineering,Tsinghua University,Bejing 100084.China [3]Smoore International Holdings Ltd.Shenzhen 518102,China

出　　处：《Particuology》2022年第8期8-17,共10页颗粒学报（英文版）

基　　金：supported by the Science Challenge Project(grant No.TZ2016001);the Strategic Priority Research Program ofthe Chinese Academy of Sciences(grant No.XDB22040402);the National Natural Science Foundation of China(grant Nos.11525211 and U1530261).

摘　　要：In many energy and combustion applications.particles experience large temperature gradients,which can affect the coagulation process due to thermophoresis.This study presents a rigorous theory of thermophoretically modified Brownian coagulation in the entire particle size regime.The theoretical derivations are based on the kinetictheory forthe free-molecular regime and the harmonic mean method for the transition regime.The coagulation kernels in different size regimes can be expressed as the basic Brownian coagulation kernel times an enhancement factor,The enhancement factor represents the coagulationrate enhancement induced by thermophoresis and is a function of specific dimensionless numbers.Based on the enhancement factor,the thermophoretic enhancement effects on particle coagulation are further analyzed under a wide range of gas and particle conditions.The results show that thermophoretic enhancement effects are ignorable in the free-molecular regime,but need to be considered in the continuum regime and the transition regime.In addition,the enhancement effects increase significantly with increase of gas temperature and temperature gradient while decrease with increase of gas pressure.The present study can improve understanding ofthermophoretic effects on Brownian coagulation in the entire size regime and provide a useful tool to calculate the coagulation rates in presence of thermophoresis.

关 键 词：THERMOPHORESIS Brownian coagulation Enhancement factor Knudsen number 

分 类 号：O17[理学—数学]