By sealing the portal at one end of tunnel and changing the transverse location of linear fire source in tunnel, the hot smoke layer, longitudinal temperature distribution and maximum temperature of linear fire source were investigated. It is found that the flame will bend under the influence of curved ceiling and hot smoke layer will be thicker when the linear fire source approaches to the side wall. The variation law of heat release rate is analyzed by considering the limiting effect of side wall and thermal feedback. By modifying the previous formula of effective ceiling height, an empirical formula for predicting longitudinal temperature distribution of linear fire sources with different aspect ratios is proposed, and the ventilation coefficient is obtained to characterized the temperature under sealing and without sealing. Moreover, the accuracy of predicted temperature under sealing is verified by using the ventilation coefficient. Based on dimensional analysis, it's concluded that the maximum temperature mainly depends on the heat release rate, and an empirical formula is proposed to predict the maximum temperature rise of linear fire sources with different aspect ratios in several transverse positions. The error of predicted values and actual values is within 13%.

通过密封隧道一端的入口并改变线性火源在隧道中的横向位置，研究了线性火源的热烟层，纵向温度分布和最高温度。结果发现，当线性火源接近侧壁时，火焰会在弯曲的天花板的影响下弯曲，并且热烟层会更厚。通过考虑侧壁和热反馈的限制效应，分析了放热率的变化规律。通过修改现有的有效顶棚高度公式，提出了一种预测长宽比不同的线性火源纵向温度分布的经验公式，并获得了通风系数来表征密封和不密封情况下的温度。而且，利用通风系数验证了密封条件下预测温度的准确性。通过尺寸分析得出结论，最高温度主要取决于放热率，并提出了经验公式来预测不同纵横比下长径比不同的线性火源的最大温升。预测值和实际值的误差在13％以内。