Evaluation of the Prediction Performance of FDS Combustion Models for the CO Concentration of Gas Fires in a Compartment

Abstract

The prediction performance of combustion models in the Fire Dynamics Simulator (FDS) were evaluated by comparing with experiment for compartment propane gas fires. The mixture fraction model in the FDS v5.5.3 and Eddy Dissipation Concept (EDC) model in the FDS v6.6.3 were adopted in the simulations. Four chemical reaction mechanisms, such as 1-step Mixing Controlled, 2-step Mixing Controlled, 3-step Mixing Controlled and 3-step Mixed (Mixing Controlled + finite chemical reactions) reactions, were implemented in the EDC model. The simulation results with each combustion model showed similar level for the temperature inside the compartment. The prediction performance of FDS with each combustion model showed significant differences for the CO concentration while no distinguished differences were identified for the O2 and CO2 concentrations. The EDC 3-step Mixing Controlled largely over-predicted the CO concentration obtained by experiment and the mixture fraction model under-predicted the experiment slightly. The EDC 3-step Mixed showed the best prediction performance for the CO concentration and the EDC 2-step Mixing Controlled also predicted the CO concentration reasonably. The EDC 1-step Mixing Controlled significantly under-predict the experimental CO concentration when the previously suggested CO yield was adopted. The FDS simulation with the EDC 1-step Mixing Controlled showed difficulties in predicting the CO2 concentration when the CO yield was modified to predict the CO concentration reasonably.

Comparison of the Flame Height of Pool Fire according to Combustion Models in the FDS

“…주요 결과로 서 환기부족 화재조건에서는 연소모델에 따른 구획실의 열 및 주요 화학적 특성에 큰 차이가 없으며, 과환기 화재조건 에서는 온도 및 농도의 상당한 차이가 발생됨이 확인되었 다. 또한 Baek 등 (11) 은 환기부족 화재조건을 갖는 구획실 내 프로판 가스화재의 실험결과를 대상으로, 연소모델에 따라 구획실 상층부에서 측정된 CO 농도에는 상당한 차이 가 있으나, O 2 , CO 2 및 내부 온도의 차이는 크지 않음을 확 인하였다. 위 선행연구들에서는 FDS Version에 따라 변경 된 난류모델 그리고 추가적인 서브 수치 및 물리 모델들의 영향이 구체적으로 평가되지 않았다.…”

Evaluation of the Prediction of B-RISK-FDS-Coupled Simulations for Multi-Combustible Fire Behavior in a Compartment

“…이러한 이유로 본 연구그룹에서는 구획실 내 가스연료 화재에 대해 화재해석에 많이 사용되고 있는 Fire dynamics simulator (FDS)의 연소모델에 대한 예측성능 검토를 수행 하였다 (1) . 이 연구에서는 실험결과와 비교 검토하여 연소모 델 예측성능 검토를 수행하였고 검토를 통해 연소모델에 따라 열발생률과 온도분포에 대한 예측성능은 큰 차이가 없지만 화학종 농도분포에 대해서는 예측성능이 달라지는 것을 확인하였다.…”