定常流条件下不同形式排水立管压力波动机理探讨

Study on air pressure transients in different building drainage and vent systems on constant flow condition

研究了三种排水立管系统定常流条件下的压力分布规律。对比了三种系统压力随立管高度的变化规律。单立管系统压力分布呈S型,设有专用通气立管的系统基本不受负压影响,特殊单立管正负压交替出现。立管内的空气流速变化决定立管内压力波动,减小空气流速和减小底部水跃深度是减小系统不利压力的理论途径。

Air pressure transient characteristics of three building drainage and vent systems on constant flow condition were investigated in this article. The comparison of the air pressure extreme values among different systems＇ heights was also covered. The single stack drainage and vent system showed severe negative pressure at the top while positive pressure occured at the bottom. If the drainage stack was accompanied with a appropriative vent stack, the system were independent of negative pressure. The special single stack drainage system was alternately affected by negative pressure and positive pressure. The air pressure transient was depended on air velocity in the stack and in theory, reducing the air velocity and height of hydraulic jump at bottom could decrease system pressure.