Modeling of heat transfer in gas-filled furnace for steel members

A heat transfer model for unprotected steel structural members was proposed in this study. The model accounts for both the variation of the steel emissivity during the fire growth and the view factor effect. The participation of the gases in the heat exchange by radiation also was discussed. The calculation of the view factor of concave steel sections was derived and justified using the heat transfer theory in a realistic situation. In addition, a new formulation incorporating the transmissivity, absorptivity, and emissivity of the participating medium into the view factor was presented. A numerical verification was conducted to validate the predicted temperatures with experimental data and a good correlation was achieved. Further, the model was simplified, while retaining its accuracy to facilitate the numerical computations carried out by the structural engineers in structural fire design.