Abstract This paper focused on studying the transverse temperature distributions induced by ceiling jet under the effect of ceiling mechanical smoke extraction system. Many test conditions were investigated by conducted reduced tunnel model experiments. These changes in fire heat release rates (HRRs) and ceiling mechanical smoke extraction velocities were all taken into consideration. The longitudinal and transverse temperature distributions beneath the ceiling were also compared in this paper, it was found that the transverse temperature decays more slowly than the longitudinal temperature without ceiling extraction. In order to reveal the effect of ceiling mechanical smoke extraction system on the transverse temperature distributions induced by ceiling jet in a tunnel, the attenuation rate of transverse temperature increases as the increasing ceiling mechanical smoke extraction velocities. The modified model for transverse temperature attenuation under the ceiling induced by tunnel fire with different ceiling mechanical smoke extraction velocities was developed by modified the characteristic radius. And the dimensionless transverse temperature decay mainly shows a piecewise function.

中文翻译：

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顶棚机械排烟系统对隧道顶棚射流横向温度衰减影响的试验研究

摘要 本文重点研究了天花板机械排烟系统作用下天花板射流引起的横向温度分布。通过进行简化的隧道模型实验研究了许多测试条件。这些火灾热释放率 (HRR) 和天花板机械排烟速度的变化都被考虑在内。本文还比较了天花板下方的纵向和横向温度分布，发现横向温度比没有天花板提取的纵向温度衰减得更慢。为了揭示天花板机械排烟系统对隧道内天花板射流引起的横向温度分布的影响，随着天花板机械排烟速度的增加，横向温度的衰减率增加。通过修正特征半径，建立了不同天花板机械排烟速度下隧道火灾引起的天花板下横向温度衰减修正模型。而无量纲横向温度衰减主要表现为分段函数。