高原环境下吸气式火灾探测器采样 管道内部流动的研究

高原环境下高灵敏度吸气式火灾探测器采样管道内部流动特征直接决定了该火灾探测器的有效探测 面积。分析了高灵敏度吸气式火灾探测器采样管道在单采样孔条件下内部流动特征;从理论上推导出在高原环 境下和常压下这种采样管道在单采样孔条件下管道内部流动速度和采样孔流动速度的关系式,给出了管道内部 流动速度相同的情况下高原环境下采样管道折损长度,为设计在高原环境下高灵敏度吸气式火灾探测器以及采 样管道提供了依据。

Research of Flow in Aspirating Lines of Fire Detection System at High Altitude

Researching flow in aspirating lines in altiplano environment can offer gist of designing air aspirating lines of HSASD(High Sensitivity Aspirating Smoke Detector)at tableland.Velocity equation of air aspirating line and velocity equation of aspirating aperture could be derived from continuity equation and dynamics equation.Average velocity of air aspirating line and average velocity of aspirating aperture could be concluded when air aspirating line had only single aspirating aperture.Contrasting average velocity of air aspirating line and aspirating aperture at high altitude and normal atmosphere pressure concluded difference of them and main factors that affected flow of air aspirating lines at high altitude.Flow velocity of air aspirating lines and aspirating aperture is mainly affected by viscosity coefficient,negative pressure at aspirating pump inlet.Equal flow velocity of air aspirating lines and aspirating aperture can be got through shortening aspirating lines length.Equation 4.14 gives a compute method of shortening aspirating lines length in altiplano environment.