Multiple fires of unequal heat release rate (HRR) is a common fire scenario in real fire accidents. Differing from most previous research assumption of identical fire sources, the unequal HRR for those fire sources is regarded as more reasonable in reality. To explore the asymmetric flow characteristics surrounding multiple fires under such circumstances, simulations of two square propane burners with the same side length but different HRRs were carried out. The HRR combination and burner separation distance were varied. The results showed that the asymmetric flow characteristic was found in both the flame and the smoke plume zone. In the flame region, the flame morphology in terms of the tilt angle is a good parameter indicating the asymmetric flow characteristic. In general, the tilt angle of the small fire is larger than that of the big fire. The tilt angle of the small fire decreases while that of the big fire increases until equaling to each other under the HRR ratio reaching unity. In the smoke plume region, the smoke plumes from the small and the big fire will converge at a certain height with some shifting distance, which is another parameter indicating the asymmetric flow characteristic. Besides, the smoke plume merging process driven by asymmetric air entrainment can be divided into three stages, namely the I) Separate stage, II) Converging stage and III) Complete coalescence stage. Correlations of the converging & coalescence height suggesting the starting point of the II and III stages were proposed.

在真实的火灾事故中，多次放热率（HRR）不相等的火灾是常见的火灾场景。与以往关于相同火源的大多数研究假设不同，对于这些火源而言，不相等的HRR在现实中被认为更为合理。为了探索在这种情况下围绕多场火灾的不对称流动特性，对两个边长相同但HRR不同的方形丙烷燃烧器进行了模拟。HRR组合和燃烧器分离距离不同。结果表明，在火焰和烟羽区域都发现了不对称的流动特性。在火焰区域，关于倾斜角的火焰形态是指示不对称流动特性的良好参数。通常，小火的倾斜角大于大火的倾斜角。在HRR比达到1时，小火的倾斜角减小，而大火的倾斜角增大，直到彼此相等。在烟羽区域中，大火和大火产生的烟羽会以一定的移动距离会聚在一定的高度，这是表明流动特性不对称的另一个参数。此外，由不对称夹带引起的烟羽合并过程可分为三个阶段，即I）分离阶段，II）会聚阶段和III）完全聚结阶段。提出了会聚和合并高度的相关性，表明了II和III阶段的起点。大火和大火产生的烟羽会在一定的高度以一定的偏移距离会聚，这是另一个表示非对称流动特性的参数。此外，由不对称夹带引起的烟羽合并过程可分为三个阶段，即I）分离阶段，II）会聚阶段和III）完全聚结阶段。提出了会聚和合并高度的相关性，表明了II和III阶段的起点。大火和大火产生的烟羽会在一定的高度以一定的偏移距离会聚，这是另一个表示非对称流动特性的参数。此外，由不对称夹带引起的烟羽合并过程可分为三个阶段，即I）分离阶段，II）会聚阶段和III）完全聚结阶段。提出了会聚和合并高度的相关性，表明了II和III阶段的起点。II）收敛阶段和III）完全合并阶段。提出了会聚和合并高度的相关性，表明了II和III阶段的起点。II）收敛阶段和III）完全合并阶段。提出了会聚和合并高度的相关性，表明了II和III阶段的起点。