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Advanced simulation methods are needed to predict the complex behavior of structures exposed to realistic fires. Fire dynamics simulator (FDS) is a computational fluid dynamics code, developed by NIST for fire related simulations. In recent years, there has been an increase in use of FDS for performance-based analysis in the area of structural fire research. This paper discusses the FDS-finite element method (FEM) simulation methodology for structural fire analysis. The general methodology is described and a validation study is presented. A data element used to transfer data from FDS to FEM codes, the adiabatic surface temperature, is discussed. A tool named fire-thermomechanical interface is applied to transfer data from FDS to ANSYS. A high temperature stress-strain model for structural steel developed by NIST is included in the FEM analysis. Compared to experimental results, the FDS-FEM method predicted both the thermal and structural responses of a steel column in a localized fire test. The column buckling time was predicted with a maximum error of 7.8%. Based on these results, this methodology has potential to be used in performance-based analysis.

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In this paper, simulating a group fire in a densely inhabited area with weak small wooden buildings, we performed reduced scale model experiments to investigate flame merging. To study this phenomenon, a lot of experiments were performed using crib and liquid fuel. In this work, however two or more square propane porous burners are used, and the flame height, heat flux, and temperature distribution on the center axis of fires are measured. Consequently, the influence of the heat release rate, the number of fire sources and the distance between fire sources upon flame merging has been investigated.It is found that each of those parameters affected flame merging, although the number of fire sources seemed to be the most important parameter.

Measurements of the heating condition of a steel beam installed beneath a ceiling and exposed to a localized fire source are made on a real-scale experiment. The data of thermal response obtained from the experiments are compared with previous small-scale experiments. The effects of the smoke layer which influences upon the heating condition of the beam are investigated through the smoke experiments setting the smoke protection soffits to the same experimental equipment. FDM-based calculation is demonstrated using the average temperature of the smoke layer for the boundary conditions to predict the thermal response of the beam. Applicability of the approximated temperature of the smoke layer is examined by comparing the numerical results of the temperature with those obtained through the experiment.

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In this study, an original small-scale demonstration plant was manufactured to produce upgraded wood fuel by torrefaction. The plant consists of a rotary-kiln type oven and a ring-die type pelletizer, and they were optimized for torrefaction based on the commercial models. We succeeded in more than 240 h operation of the torrefaction oven and produced 2.3 t of torrefied chips from raw Japanese cedar chips without drying. The energy yield of the torrefied chips was more than double the energy yield of conventional charcoal chips. The average length of the torrefied pellets was 7.4 mm, which is shorter than the length of the normal wood pellets. In the combustion test using a cone calorimeter, no delay in ignition time and small decease in heat release rate were seen for torrefied pellets in comparison with the results of normal pellets.