A Eulerian population balance/Monte Carlo approach for simulating laminar aluminum dust flames

作     者：Fabian Sewerin Jannis Finke Fabian Sewerin;Jannis Finke

作者机构：Emmy Noether Group for Dispersed Multiphase FlowsChair of Mechanical Process EngineeringOtto-von-Guericke-Universität MagdeburgUniversitätsplatz 239106 MagdeburgGermany 

出 版 物：《Particuology》 (颗粒学报（英文版）)

年 卷 期：2024年第88卷第5期

页      面：323-343页

核心收录：

学科分类：08[工学] 0817[工学-化学工程与技术] 0805[工学-材料科学与工程（可授工学、理学学位）] 080502[工学-材料学] 

基　　金：funded by the Deutsche Forschungsgemeinschaft(DFG German Research Foundation)with in the scope of the Emmy Noether Program(Project number 443546539). 

主　　题：Metal dust combustion Aluminum Population balance Eulerian Monte Carlo 

摘      要：Recently,metal powders have been conceptualized as carbon-free recyclable energy carriers that may form a cornerstone of a sustainable energy economy.The combustion of metal dusts in oxidizing atmospheres is exothermal and yields oxide particles that could,potentially,be retrieved and,subsequently,recharged by conversion to pure metals using green primary energy sources.As a step towards a predictive tool for designing metal dust combustors,we present a fully Eulerian modelling approach for laminar particle-laden reactive flows that is,conceptually,based on a population balance description of the dispersed particles and relies on a stochastic Eulerian solution strategy.While the population balance equation(PBE)is formulated for the number-weighted distribution of characteristic properties among all particles near a spatial location,it is kinetically informed by the rates at which mass,momentum and heat are exchanged between the carrier gas and the particulate phase on the single particle level.Within the scope of the Eulerian Monte Carlo solution scheme,the property distribution is discretely represented in terms of the total number density and a finite number of property samples and the computational work is channelled towards the Eulerian estimation of mean particle properties.For the case of reactive aluminum particles,we combine a kinetic description of the gas-particle heat and mass transfer with a transport-limited continuum formulation to obtain rate expressions that are valid across the entire particle size range from the free molecular through the continuum regime.Besides velocity,the particle properties include only the particle mass,temperature and oxide mass fraction.This set of thermochemical degrees of freedom is retained also as phase transitions due to melting occur,drawing on a smooth blend of the solid and liquid thermodynamic and material properties.The particle-level formulation encompasses aluminum evaporation,surface oxidation,scavenging of oxide smoke,oxide evaporation/dissociation and radiation.After investigating how these effects translate,through the PBE,to the particle population level and affect the combustion in a homogeneous dust reactor,we analyze the combustion of an aluminum dust in a counterflow flame and validate predictions of the particles’centerline velocity profile and the flame speed by comparison with available experimental data.Concomitantly,nitrogen oxide emissions are investigated along with the particle burnout and outlet size distribution.