在受限空间内,针对稳定热释放速率火源,运用经验公式与压力相似模型,推导出顶棚射流重力流区域在烟气发展段与稳定段温度随气压变化的关系.理论分析表明,受限空间内顶棚射流与竖直壁面碰撞前,高原低压环境探测器位置处温度与环境温度的差与在常压环境下的比值近似等于环境温度比；而当烟气沉降达到稳定状态时,二者比值为当地压强比的2/3次幂.利用合肥(0.1 MPa)与拉萨(约0.067 MPa)两地的国际标准火实验间进行乙醇池火燃烧实验验证,结果表明,实验数据分析曲线与理论推导的结果在误差允许的范围内能够得到很好的吻合.该理论推导结果可f为高原低压环境火灾探测器的选型、调试和设计安装提供支撑和参考.%According to the theoretical analysis and experimental validation, the smoke temperature of fire with a steady heat release rate in gravity flow zone under a ceiling of confined space is analyzed under different atmospheric pressure. The results show that the temperature difference ratio of this point to the environment is equal to the envi-ronment temperature ratio of low atmospheric pressure to normal pressure at the smoke layer development stage. How-ever, the ratio is equal to 2/3 power of pressure ratio when the smoke layer enters the steady state. The experiments were done in Hefei (about 0.1 Mpa) and Lhasa (about 0.067 Mpa) in order to validate the theoretical analysis. The etha-nol fire (43.5 cm × 43.5 cm) is chosen as the test fire in the ISO fire detection room. The results show that the curves of theoretical prediction and experimental test can fit well. Therefore, the results can serve as the reference to the selec-tion, design and installation of fire detectors in high altitude area such as Tibet.
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