This study experimentally investigates fire behaviors of double fires with asymmetric heat release rates in a naturally ventilated tunnel including flame merging and longitudinal ceiling gas temperature distribution. The comparison between double fires with symmetric and asymmetric heat release rates was also made. The results show that the flame merging possibility increases as the heat release rate on one side increases. The ratio of heat release rates between double fire sources still influences the flame merging possibility under a given total heat release rate. The ceiling gas temperature distribution is related to the flame merging state. As the fire separation distance increases from zero, the position of peak temperature is closer to the fire source with a larger heat release rate due to a smaller flame tilt angle. For scenarios with mean flame merged, the ceiling gas temperature distribution on both sides is equal. For scenarios with mean flame not merged, the ceiling gas temperature on the side with a larger heat release rate is much higher. Finally, different empirical models are established to predict the excess ceiling gas temperature attenuation, considering different flame merging states and smoke spread regions.

中文翻译：

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自然通风隧道内不对称放热率双重火灾火灾行为试验研究

本研究通过实验研究了自然通风隧道中热释放率不对称的双重火灾的火灾行为，包括火焰合并和纵向天花板气体温度分布。还对对称和不对称热释放率的双火进行了比较。结果表明，随着一侧放热率的增加，火焰合并的可能性增加。在给定总放热率的情况下，双火源之间的放热率之比仍然影响着火焰合并的可能性。顶棚气体温度分布与火焰融合状态有关。随着火距从零开始增加，峰值温度的位置越接近火源，由于火焰倾斜角越小，热释放速率越大。对于平均火焰合并的场景，两侧的天花板气体温度分布是相等的。对于平均火焰未合并的场景，放热率较大一侧的天花板气体温度要高得多。最后，考虑不同的火焰融合状态和烟雾扩散区域，建立不同的经验模型来预测过量天花板气体温度衰减。