Fire in large-volume buildings poses separate and distinct challenges from compartmented spaces. In particular, the risk it poses on life safety is mostly due to the smoke it produces, its effects on the evacuation process, and how it can affect the firefighters when they approach the building to fight the fire and rescue the occupants. This is why smoke control in large-volume enclosures is of utter importance for life safety, property protection and business continuity. This research presents an experimental and numerical study of the smoke dynamics from four fire sources (combined heat release rate of 5.2 MW) with different ignition times and under transient ventilation conditions, inside a 20 m high cubic atrium. Temperature measurements in the plume and close to the walls have been recorded using 59 thermocouples. The data was used in the determination of the smoke layer interface height, with the least-square and the N-Percent methods. Results show that significantly worse conditions are induced by multiple sources than those in a single fire of equal power. The results have been obtained using the computational fluid dynamics code FDS (Fire Dynamics Simulator, v6.7.1). The comparison shows that in the far field the temperature predictions are accurate inside the smoke layer (10 m and 15 m) with discrepancies lower than 10%, whereas higher significant discrepancies were observed at the smoke layer interface, i.e. 5 m high, with discrepancies up to 20%. Furthermore, a grid analysis has been performed showing that grid resolutions, D*/δ, based on the global HRR of the fire might be sufficient to predict the fire induced conditions far from the fire. The analysis confirmed the applicability of FDS to the assessment of the smoke dynamics under complex fire conditions away from flames. Ultimately, the present work shows the importance of considering fires with multiple sources due to the faster smoke production compared with single fires.

大型建筑中的火灾与分隔空间构成不同的挑战。特别是，它对生命安全构成的风险主要归因于其产生的烟雾，其对疏散过程的影响，以及当消防员进入建筑物灭火并救助人员时，它如何影响消防员。这就是为什么大容量机柜中的烟雾控制对于生命安全，财产保护和业务连续性至关重要的原因。这项研究提供了一个实验和数值研究，研究了在20 m高的立方体中庭内，四个点火源（组合放热率为5.2 MW）具有不同的点火时间和瞬态通风条件下的烟气动力学。使用59个热电偶记录了烟羽中和靠近壁的温度测量值。N-百分比方法。结果表明，与相同功率的单次火灾相比，多种来源引起的情况要差得多。使用计算流体动力学代码FDS（Fire Dynamics Simulator，v6.7.1）获得了结果。比较表明，在远场中，烟雾层（10 m和15 m）内的温度预测是准确的，差异小于10％，而在烟雾层界面（即5 m高）处观察到较高的显着差异，且存在差异高达20％。此外，进行了网格分析，显示出网格分辨率D * /δ，基于火灾的全局HRR，可能足以预测远离火灾的火灾诱发条件。分析证实了FDS适用于评估远离火焰的复杂火灾条件下的烟雾动态。最终，目前的工作表明，考虑到与单一火灾相比产生烟雾更快的原因，考虑多源火灾的重要性。