### Abstract

A mathematical model along with a numerical solution procedure is presented for the simulation of flameless combustion (smoldering) of a solid in a stream of air. By assuming a global single-step combustion reaction, the problem is formulated via conservation equations of mass, species, linear momentum, and energy. Conservation equations are developed by volume averaging the microscopic conservation equations of the constituent phases (i.e., gaseous mixture, solid fuel, and ash). The model accounts for conduction in the solid, thermal radiation from the solid, and forced and natural convection flow and heat transfer in the gas stream. Also included in the problem formulation are the effects of transport processes such as the heatup and ignition of the solid sample, the smoldering of the solid, the motion of the burning front, and the formation of ash and transport of gas and heat in it. The transient two-dimensional governing equations of the problem, in terms of primitive variables, are discretized over nonuniform control-volumes and solved by an iterative numerical procedure. Different aspects of the model and solution procedure are also discussed. As a test problem, the smoldering of standard samples of charcoal (wood-coal) in a limiting oxygen index (LOI) flammability test apparatus is modeled. The results of the smoldering simulations are presented in terms of the field variations of velocity, composition, and temperature of the gas in the test chamber, the temperature distribution in the solid and ash, and the temporal position and velocity of the smoldering/burning front. The calculated transient burning rates are compared with the experimental data obtained in a LOI apparatus.

Original language | English (US) |
---|---|

Pages (from-to) | 170-182 |

Number of pages | 13 |

Journal | Combustion and Flame |

Volume | 95 |

Issue number | 1-2 |

DOIs | |

State | Published - 1993 |

### Fingerprint

### ASJC Scopus subject areas

- Energy Engineering and Power Technology
- Fuel Technology
- Mechanical Engineering

### Cite this

*Combustion and Flame*,

*95*(1-2), 170-182. https://doi.org/10.1016/0010-2180(93)90059-C

**Numerical modeling of two-dimensional smoldering processes.** / Moallemi, M. Karim; Zhang, Hui; Kumar, Sunil.

Research output: Contribution to journal › Article

*Combustion and Flame*, vol. 95, no. 1-2, pp. 170-182. https://doi.org/10.1016/0010-2180(93)90059-C

}

TY - JOUR

T1 - Numerical modeling of two-dimensional smoldering processes

AU - Moallemi, M. Karim

AU - Zhang, Hui

AU - Kumar, Sunil

PY - 1993

Y1 - 1993

N2 - A mathematical model along with a numerical solution procedure is presented for the simulation of flameless combustion (smoldering) of a solid in a stream of air. By assuming a global single-step combustion reaction, the problem is formulated via conservation equations of mass, species, linear momentum, and energy. Conservation equations are developed by volume averaging the microscopic conservation equations of the constituent phases (i.e., gaseous mixture, solid fuel, and ash). The model accounts for conduction in the solid, thermal radiation from the solid, and forced and natural convection flow and heat transfer in the gas stream. Also included in the problem formulation are the effects of transport processes such as the heatup and ignition of the solid sample, the smoldering of the solid, the motion of the burning front, and the formation of ash and transport of gas and heat in it. The transient two-dimensional governing equations of the problem, in terms of primitive variables, are discretized over nonuniform control-volumes and solved by an iterative numerical procedure. Different aspects of the model and solution procedure are also discussed. As a test problem, the smoldering of standard samples of charcoal (wood-coal) in a limiting oxygen index (LOI) flammability test apparatus is modeled. The results of the smoldering simulations are presented in terms of the field variations of velocity, composition, and temperature of the gas in the test chamber, the temperature distribution in the solid and ash, and the temporal position and velocity of the smoldering/burning front. The calculated transient burning rates are compared with the experimental data obtained in a LOI apparatus.

AB - A mathematical model along with a numerical solution procedure is presented for the simulation of flameless combustion (smoldering) of a solid in a stream of air. By assuming a global single-step combustion reaction, the problem is formulated via conservation equations of mass, species, linear momentum, and energy. Conservation equations are developed by volume averaging the microscopic conservation equations of the constituent phases (i.e., gaseous mixture, solid fuel, and ash). The model accounts for conduction in the solid, thermal radiation from the solid, and forced and natural convection flow and heat transfer in the gas stream. Also included in the problem formulation are the effects of transport processes such as the heatup and ignition of the solid sample, the smoldering of the solid, the motion of the burning front, and the formation of ash and transport of gas and heat in it. The transient two-dimensional governing equations of the problem, in terms of primitive variables, are discretized over nonuniform control-volumes and solved by an iterative numerical procedure. Different aspects of the model and solution procedure are also discussed. As a test problem, the smoldering of standard samples of charcoal (wood-coal) in a limiting oxygen index (LOI) flammability test apparatus is modeled. The results of the smoldering simulations are presented in terms of the field variations of velocity, composition, and temperature of the gas in the test chamber, the temperature distribution in the solid and ash, and the temporal position and velocity of the smoldering/burning front. The calculated transient burning rates are compared with the experimental data obtained in a LOI apparatus.

UR - http://www.scopus.com/inward/record.url?scp=0027686486&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=0027686486&partnerID=8YFLogxK

U2 - 10.1016/0010-2180(93)90059-C

DO - 10.1016/0010-2180(93)90059-C

M3 - Article

VL - 95

SP - 170

EP - 182

JO - Combustion and Flame

JF - Combustion and Flame

SN - 0010-2180

IS - 1-2

ER -