Abstract: Building fire is one of the most important research fields in fire science, and the temperature distribution of the spill plume along the facade is very important for the risk assessment and prevention design of the building. Although many scholars have studied the vertical temperature distribution of spill plumes on vertical facade, there are few studies on temperature distribution along sloped facade. This paper aims to reveal the characteristics of longitudinal temperature distribution of spill plumes along the sloped facade in building fire, and establishes a predicted correlation for the temperature distribution along sloped facade. Based on Froude similarity theory, a 1∶2 medium-scale-combustion chamber was built in the FDS to carry out numerical simulation research. The validation of the numerical model was confirmed through mesh sensitivity test and the comparison with experimental data. The dimensions of the combustion chamber were 3.78 m2.36 m1.6 m. A variable-angle concrete slab (2.36 m in length and 7.55 m in height) was installed above the opening of the combustion chamber to simulate the facade of the building. To investigate the temperature distribution of spill plumes along sloped facade wall, a total of 64 scenarios were considered with 4 different dimensions of rectangular openings(0.52 m0.65 m, 0.78 m0.52 m, 0.78 m0.65 m, 0.78 m0.78 m), 4 different facade wall angles (0°,10°,15°,20°) and 4 different heat release rates respectively. It is found that: (1) When the dimension of the openings and the heat release rates are constant, the temperature along the sloped facade (θ＞0°) is significantly higher than that along the vertical facade at the same measurement point (θ=0°). (2) When the angle of facade wall is set as 20°, the temperature at the same measurement point in the plume region is the highest among the four designed angles. (3) When the angle of facade wall is less than 20°, the temperature at the same measurement point gradually increases with the angle of the facade θ. (4) When the dimension of the openings and the angle of facade are the constant, with the increase of heat release rates, the maximum temperatures of the spill plume is almost constant. For further research on spill fire plume temperature distribution characteristics of sloped facade, the Z-Zn in classical theory is modified by 1+sinθ. It is found that the spill plume temperatures of the same opening dimension and heat release rate with different angles of facade wall collapse well. Based on these results, a predicted correlation of the temperature along the sloped facade is established, whose facade wall angles are in the range of 0<θ<20°.The results in this paper are based on the sloped angle between 0° and 20°. It needs to be further studied that whether the temperature distribution of spill plume conforms to this law when the sloped angle is greater than 20°.

Key words: building fire; sloped facade wall; numerical simulation; temperature distribution