Experimental and Numerical Study on Operational Characteristics of a Single Outlet Siphonic Drainage System in Large Public Buildings

For large public buildings, a siphon drainage system facilitates good on building safety and operation. However, conventional siphon drainage systems are designed based on full pipe flow, which is suitable only under specific criteria and cannot assess the detailed flow characteristics from priming to the entire siphon formation process. In this paper, a full-size experimental platform for a single outlet siphon drainage system is proposed to research the flow characteristics of the siphon drainage. Then, a full-scale numerical model of a siphon drainage system is established and the process of the siphon drainage is simulated by the volume of fluid model. The accuracy of the numerical model is verified by comparing its results with the experimental data. Moreover, a sensitivity analysis of different pipeline structure parameters on siphon priming time is presented, which shows that a larger length and diameter of the suspension pipe and a larger riser pipe diameter prolong the siphon formation time. Finally, theoretical formulas are derived to describe the mathematical relationships between the suspension pipe length and maximum displacement and the suspension pipe length and siphon priming time.