Analysis of grate firing of wood with numerical flow simulation

Marko Huttunen, Lars Kjäldman, Jaakko Saastamoinen

Research output: Contribution to journalArticleScientificpeer-review

Abstract

Flow, combustion and heat transfer in a grate fired furnace burning wood with a heating power of 1 MW has been analysed numerically using the CFD software FLUENT 6.0. Such furnaces are used for example in hot-water boilers of real estate heating systems. The submodels of FLUENT are used for turbulence, for combustion of devolatilised fuel and for radiative heat transfer. The user-defined functions of FLUENT are used to incorporate a submodel for the description of drying, pyrolysis, combustion and gasification of wood on a grate. The grate submodel considers the interactions between the fuel bed and gas phase above the bed, and it predicts the temperature of the fuel bed and the temperature and the composition of the gas mixture released into the furnace from the bed. Subsequently, these are used to calculate the source terms for the flow modelling. The fuel bed model is employed together with the flow simulation. According to the results of the two simulation cases that are considered, minor changes to the construction of the present furnace could considerably reduce CO emissions. The predictions also show that the present fuel bed model is rather insensitive to the conditions of the gas phase above the bed but are more likely to be affected by the properties of the fuel bed.
Original languageEnglish
Article number200401
JournalIFRF Combustion Journal
Publication statusPublished - 2004
MoE publication typeA1 Journal article-refereed

Fingerprint

Flow simulation
Wood
Furnaces
Heat transfer
Heating
Gases
Gasification
Gas mixtures
Boilers
Drying
Computational fluid dynamics
Pyrolysis
Turbulence
Temperature
Chemical analysis

Keywords

  • grate furnace
  • combustion
  • computational fluid dynamics

Cite this

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title = "Analysis of grate firing of wood with numerical flow simulation",
abstract = "Flow, combustion and heat transfer in a grate fired furnace burning wood with a heating power of 1 MW has been analysed numerically using the CFD software FLUENT 6.0. Such furnaces are used for example in hot-water boilers of real estate heating systems. The submodels of FLUENT are used for turbulence, for combustion of devolatilised fuel and for radiative heat transfer. The user-defined functions of FLUENT are used to incorporate a submodel for the description of drying, pyrolysis, combustion and gasification of wood on a grate. The grate submodel considers the interactions between the fuel bed and gas phase above the bed, and it predicts the temperature of the fuel bed and the temperature and the composition of the gas mixture released into the furnace from the bed. Subsequently, these are used to calculate the source terms for the flow modelling. The fuel bed model is employed together with the flow simulation. According to the results of the two simulation cases that are considered, minor changes to the construction of the present furnace could considerably reduce CO emissions. The predictions also show that the present fuel bed model is rather insensitive to the conditions of the gas phase above the bed but are more likely to be affected by the properties of the fuel bed.",
keywords = "grate furnace, combustion, computational fluid dynamics",
author = "Marko Huttunen and Lars Kj{\"a}ldman and Jaakko Saastamoinen",
year = "2004",
language = "English",
journal = "IFRF Combustion Journal",
issn = "1562-479X",
publisher = "International Flame Research Foundation IFRF",

}

Analysis of grate firing of wood with numerical flow simulation. / Huttunen, Marko; Kjäldman, Lars; Saastamoinen, Jaakko.

In: IFRF Combustion Journal, 2004.

Research output: Contribution to journalArticleScientificpeer-review

TY - JOUR

T1 - Analysis of grate firing of wood with numerical flow simulation

AU - Huttunen, Marko

AU - Kjäldman, Lars

AU - Saastamoinen, Jaakko

PY - 2004

Y1 - 2004

N2 - Flow, combustion and heat transfer in a grate fired furnace burning wood with a heating power of 1 MW has been analysed numerically using the CFD software FLUENT 6.0. Such furnaces are used for example in hot-water boilers of real estate heating systems. The submodels of FLUENT are used for turbulence, for combustion of devolatilised fuel and for radiative heat transfer. The user-defined functions of FLUENT are used to incorporate a submodel for the description of drying, pyrolysis, combustion and gasification of wood on a grate. The grate submodel considers the interactions between the fuel bed and gas phase above the bed, and it predicts the temperature of the fuel bed and the temperature and the composition of the gas mixture released into the furnace from the bed. Subsequently, these are used to calculate the source terms for the flow modelling. The fuel bed model is employed together with the flow simulation. According to the results of the two simulation cases that are considered, minor changes to the construction of the present furnace could considerably reduce CO emissions. The predictions also show that the present fuel bed model is rather insensitive to the conditions of the gas phase above the bed but are more likely to be affected by the properties of the fuel bed.

AB - Flow, combustion and heat transfer in a grate fired furnace burning wood with a heating power of 1 MW has been analysed numerically using the CFD software FLUENT 6.0. Such furnaces are used for example in hot-water boilers of real estate heating systems. The submodels of FLUENT are used for turbulence, for combustion of devolatilised fuel and for radiative heat transfer. The user-defined functions of FLUENT are used to incorporate a submodel for the description of drying, pyrolysis, combustion and gasification of wood on a grate. The grate submodel considers the interactions between the fuel bed and gas phase above the bed, and it predicts the temperature of the fuel bed and the temperature and the composition of the gas mixture released into the furnace from the bed. Subsequently, these are used to calculate the source terms for the flow modelling. The fuel bed model is employed together with the flow simulation. According to the results of the two simulation cases that are considered, minor changes to the construction of the present furnace could considerably reduce CO emissions. The predictions also show that the present fuel bed model is rather insensitive to the conditions of the gas phase above the bed but are more likely to be affected by the properties of the fuel bed.

KW - grate furnace

KW - combustion

KW - computational fluid dynamics

M3 - Article

JO - IFRF Combustion Journal

JF - IFRF Combustion Journal

SN - 1562-479X

M1 - 200401

ER -