On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process

Reactive systems in a thermochemical conversion domain are modelled considering N-specie, 1-energy and 2-mass conservation equations assuming negligible pressure gradient resulting in N+3 non-linear coupled PDE system with dependency on thermodynamic and transport properties. Typically, simplistic t...

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Autores principales:	Asheruddin N Mohammed, Shivapuji Anand M, Srinivasaiah Dasappa
Formato:	article
Lenguaje:	EN FR
Publicado:	EDP Sciences 2021
Materias:	thermochemical conversion numerical simplification lewis number Environmental sciences GE1-350
Acceso en línea:	https://doaj.org/article/77b76ea2ba324bc083d0ac96596127a4
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spelling	oai:doaj.org-article:77b76ea2ba324bc083d0ac96596127a42021-11-12T11:44:34ZOn the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process2267-124210.1051/e3sconf/202132102015https://doaj.org/article/77b76ea2ba324bc083d0ac96596127a42021-01-01T00:00:00Zhttps://www.e3s-conferences.org/articles/e3sconf/pdf/2021/97/e3sconf_icchmt2021_02015.pdfhttps://doaj.org/toc/2267-1242Reactive systems in a thermochemical conversion domain are modelled considering N-specie, 1-energy and 2-mass conservation equations assuming negligible pressure gradient resulting in N+3 non-linear coupled PDE system with dependency on thermodynamic and transport properties. Typically, simplistic temperature-dependent polynomials are chosen for estimating thermal conductivity and specific heat, however, the estimation of mass diffusion coefficient (Di;mix) follows a complicated procedure involving kinetic theory culminating in Chapman-Enskog equation. This renders the solution computationally intensive. The complexity is simplified by assuming a constant Lewis (Le) number, a standard practice in the analytical solution for conventional reactive systems. In fixing Le, (Di;mix) is equated to thermal diffusivity (a ratio of thermodynamic properties) resulting in the specie and energy equation yielding a similar solution and collapse of N+3 system of simultaneous equations to 3 equations. The current article explores the validity and limitation of assuming constant Le in the simulation of char conversion process in air and steam. Results of char conversion are compared for fixed Le and D estimated with Chapman{Enskog expresion. The analysis suggests that Le remains invariant only under a severely restricted set of conditions. Fixing Le influences, the conversion process either over-/under-predicting the conversion time scales and the product gas composition.Asheruddin N MohammedShivapuji Anand MSrinivasaiah DasappaEDP Sciencesarticlethermochemical conversionnumerical simplificationlewis numberEnvironmental sciencesGE1-350ENFRE3S Web of Conferences, Vol 321, p 02015 (2021)
institution	DOAJ
collection	DOAJ
language	EN FR
topic	thermochemical conversion numerical simplification lewis number Environmental sciences GE1-350
spellingShingle	thermochemical conversion numerical simplification lewis number Environmental sciences GE1-350 Asheruddin N Mohammed Shivapuji Anand M Srinivasaiah Dasappa On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
description	Reactive systems in a thermochemical conversion domain are modelled considering N-specie, 1-energy and 2-mass conservation equations assuming negligible pressure gradient resulting in N+3 non-linear coupled PDE system with dependency on thermodynamic and transport properties. Typically, simplistic temperature-dependent polynomials are chosen for estimating thermal conductivity and specific heat, however, the estimation of mass diffusion coefficient (Di;mix) follows a complicated procedure involving kinetic theory culminating in Chapman-Enskog equation. This renders the solution computationally intensive. The complexity is simplified by assuming a constant Lewis (Le) number, a standard practice in the analytical solution for conventional reactive systems. In fixing Le, (Di;mix) is equated to thermal diffusivity (a ratio of thermodynamic properties) resulting in the specie and energy equation yielding a similar solution and collapse of N+3 system of simultaneous equations to 3 equations. The current article explores the validity and limitation of assuming constant Le in the simulation of char conversion process in air and steam. Results of char conversion are compared for fixed Le and D estimated with Chapman{Enskog expresion. The analysis suggests that Le remains invariant only under a severely restricted set of conditions. Fixing Le influences, the conversion process either over-/under-predicting the conversion time scales and the product gas composition.
format	article
author	Asheruddin N Mohammed Shivapuji Anand M Srinivasaiah Dasappa
author_facet	Asheruddin N Mohammed Shivapuji Anand M Srinivasaiah Dasappa
author_sort	Asheruddin N Mohammed
title	On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
title_short	On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
title_full	On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
title_fullStr	On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
title_full_unstemmed	On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process
title_sort	on the mathematical model simplification using constant lewis number – impact assessment on heterogeneous char conversion process
publisher	EDP Sciences
publishDate	2021
url	https://doaj.org/article/77b76ea2ba324bc083d0ac96596127a4
work_keys_str_mv	AT asheruddinnmohammed onthemathematicalmodelsimplificationusingconstantlewisnumberimpactassessmentonheterogeneouscharconversionprocess AT shivapujianandm onthemathematicalmodelsimplificationusingconstantlewisnumberimpactassessmentonheterogeneouscharconversionprocess AT srinivasaiahdasappa onthemathematicalmodelsimplificationusingconstantlewisnumberimpactassessmentonheterogeneouscharconversionprocess
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On the mathematical model simplification using constant Lewis number – Impact assessment on heterogeneous char conversion process

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