Numerical Simulation of Coupled Pyrolysis and Combustion Reactions with Directly Measured Fire Properties

Abstract

In this study, numerical simulations of coupled solid-phase reactions (pyrolysis) and gas-phase reaction (combustion) were conducted. During a fire, both charring and non-charring materials undergo a pyrolysis as well as a combustion reaction. A three-dimensional computational fluid dynamics (CFD)-based fire model (Fire Dynamics Simulator, FDS version 6.2) was used for simulating the PMMA (non-charring), pine (charring), wool (charring) and cotton (charring) flaming fire experiments conducted with a cone calorimeter at 50 and 30 kW/m2 irradiance. The inputs of chemical kinetics and the heat of reaction were obtained from sample mass change and enthalpy data in TGA and differential scanning calorimetry (DSC) tests and the flammability parameters were obtained from cone calorimeter experiments. An iso-conversional analytical model was used to obtain the kinetic triplet of the above materials. The thermal properties related to heat transfer were also mostly obtained in house. All these directly measured fire properties were inputted to FDS in order to model the coupled pyrolysis–combustion reactions to obtain the heat release rate (HRR) or mass loss. The comparison of the results from the simulations of non-prescribed fires show that experimental HRR or mass loss curve can be reasonably predicted if input parameters are directly measured and appropriately used. Some guidance to the optimization and inverse analysis technique to generate fire properties is provided.

Experimental Study on Flammability and Flame Spread Characteristics of Polyvinyl Chloride (PVC) Cable

“…As the number of cables increases, the width of the cable rises, and thus the dimensionless flame height of the cable decreases according to Formula (5). This is consistent with the predicted trend of the Formula (3).…”

“…This paper determines flame-spread rate of PVC cable based on the moving speed of the pyrolysis front. According to the TG-DTG-DSC-MS curve of rubber combustion, the pyrolysis of the rubber starts at about 190 • C, and the pyrolysis rate at this temperature can reach 100% [5,27]. To show the range of the pyrolysis area more clearly, the temperature from 190 • C to 225 • C is selected in the infrared video as the pyrolysis temperature, from which the change of the pyrolysis front position over time can be obtained, as shown in Figure 9.…”

“…Some works have been conducted concerning pyrolysis behavior, combustion property, and fire toxicity of cable materials. Experimental and numerical studies were conducted by Moinuddin et al [5] on coupled solid-phase reactions (pyrolysis) and gas-phase reaction (combustion) for both charring and non-charring materials. Fernandez-Pello et al [6] evaluated the fire resistance of cables commonly used in electrical facilities after obtaining the ignition time and fire-spread rate of the cables impacted by external radiant heat flux.…”

Flammability analysis of military fabrics

“…Lowest EHC observed in cotton fabrics. However, the small mass of samples may affect the data accuracy as well as the presence of moisture as reported in Moinuddin et al, (Moinuddin et al, 2020) the effective heat of combustion which in turn affects the simulation outcome.…”

Measurement of Pyrolysis Properties for Fire Spread Simulation of Cables

“…케이블의 화재 확산 시뮬레이션을 위한 열분해물성은 Lyon (27,28) (23,24) 결과적으로 활성화 에너지 . (  의 정량적인 ) 비교는 케이블 화재 확산 예측을 위하여 반드시 선행되어 한 다.…”