{"title":"Heat and Mass Transfer and Chemical Kinetics in the Combustion of Polymethyl Methacrylate in Air under Free Convection","authors":"T. A. Bolshova, A. G. Shmakov","doi":"10.1134/s0010508223060047","DOIUrl":null,"url":null,"abstract":"<h3 data-test=\"abstract-sub-heading\">Abstract</h3><p>Heat and mass transfer processes and the rate of fuel oxidation are the determining parameters of combustion of non-premixed gaseous fuel–oxidizer flows and solid-fuel combustion in a gaseous oxidizer. A correct description of these processes is of both scientific and practical interest. The influence of the kinetics of chemical reactions and diffusion of fuel molecules on the thermal and chemical structure of the flame forming around a polymethyl methacrylate (PMMA) sphere in air under natural convection has been studied by numerical simulation. The three-dimensional gas flow around the solid body has been calculated using the full Navier–Stokes equations for a multicomponent mixture taking into account diffusion and heat transfer between the surface and gas, convection, and radiative heat transfer. The kinetic model represents the conjugate reactions both on the condensed material surface and in the gas phase. The formation of the gaseous fuel methyl methacrylate (MMA) on the surface is described by an effective one-step pyrolysis reaction of PMMA. The oxidation of MMA in the gas phase is described by the global reaction C<sub>5</sub>H<sub>8</sub>O<sub>2</sub> + 6O<sub>2</sub> <span>\\(\\to\\)</span> 5CO<sub>2</sub> + 4H<sub>2</sub>O. It has been found that the temperature and species concentration profiles in the flame practically do not depend on the rate constant of this reaction provided that the characteristic reaction time is much less than the characteristic time of MMA diffusion. It has been shown that varying the MMA diffusion coefficient has a significant effect on the thermal and chemical structure of the flame. Increasing the MMA diffusion coefficient increases the maximum flame temperature. The results of the study show that the transport properties of compounds required to calculate their transport coefficients are among the most important parameters for accurate CFD simulation.</p>","PeriodicalId":10509,"journal":{"name":"Combustion, Explosion, and Shock Waves","volume":"1 1","pages":""},"PeriodicalIF":0.9000,"publicationDate":"2024-01-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Combustion, Explosion, and Shock Waves","FirstCategoryId":"5","ListUrlMain":"https://doi.org/10.1134/s0010508223060047","RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ENERGY & FUELS","Score":null,"Total":0}
引用次数: 0
Abstract
Heat and mass transfer processes and the rate of fuel oxidation are the determining parameters of combustion of non-premixed gaseous fuel–oxidizer flows and solid-fuel combustion in a gaseous oxidizer. A correct description of these processes is of both scientific and practical interest. The influence of the kinetics of chemical reactions and diffusion of fuel molecules on the thermal and chemical structure of the flame forming around a polymethyl methacrylate (PMMA) sphere in air under natural convection has been studied by numerical simulation. The three-dimensional gas flow around the solid body has been calculated using the full Navier–Stokes equations for a multicomponent mixture taking into account diffusion and heat transfer between the surface and gas, convection, and radiative heat transfer. The kinetic model represents the conjugate reactions both on the condensed material surface and in the gas phase. The formation of the gaseous fuel methyl methacrylate (MMA) on the surface is described by an effective one-step pyrolysis reaction of PMMA. The oxidation of MMA in the gas phase is described by the global reaction C5H8O2 + 6O2\(\to\) 5CO2 + 4H2O. It has been found that the temperature and species concentration profiles in the flame practically do not depend on the rate constant of this reaction provided that the characteristic reaction time is much less than the characteristic time of MMA diffusion. It has been shown that varying the MMA diffusion coefficient has a significant effect on the thermal and chemical structure of the flame. Increasing the MMA diffusion coefficient increases the maximum flame temperature. The results of the study show that the transport properties of compounds required to calculate their transport coefficients are among the most important parameters for accurate CFD simulation.
期刊介绍：
Combustion, Explosion, and Shock Waves a peer reviewed journal published in collaboration with the Siberian Branch of the Russian Academy of Sciences. The journal presents top-level studies in the physics and chemistry of combustion and detonation processes, structural and chemical transformation of matter in shock and detonation waves, and related phenomena. Each issue contains valuable information on initiation of detonation in condensed and gaseous phases, environmental consequences of combustion and explosion, engine and power unit combustion, production of new materials by shock and detonation waves, explosion welding, explosive compaction of powders, dynamic responses of materials and constructions, and hypervelocity impact.
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