Mathematical model and experiment analysis of pressure fluctuation inside dual-stack drainage system in residential buildings

The final velocity was put forward to study the water flow characteristics inside the building drainage system, however, it is more suitable for low-rise and multi-storey buildings, not for high-rise buildings. This study revealed the drainage transient characteristics of double stack drainage system in high-rise residential buildings. Based on the final velocity, the air-water interaction mechanism and two-phase flow conditions in high-rise residential drainage stacks were discussed. An influence model of drainage system flow rate on pressure fluctuation under the change of state parameters such as ventilation rate, pipe wall roughness and building height was established. The pressure limit and flow rate data were obtained through full-scale experiments. The pressure limit and flow rate model were simplified to P-n = A . Q(2) + B . Q(1.81) + C. After data verified, the fitting coefficient A, B and C were linear to the floor height.