Researches on Unsteady Three-phase Flow Characteristics of Wastewater System of Civil Aircraft

Abstract

The wastewater system is an important part of civil aircraft. The effective sewage discharge is closely related to the ride comfort and health of passengers. Euler method is used to simulate the gas-liquid-solid three-phase flow in wastewater system,and the effect of flight height and working condition of toilet on wastewater emission is analyzed. Results show that:when only the farthest toilet works,with the increase of flight altitude,the core peak time of waste water flow is brought forward,and the time required for wastewater to be completely discharged are significantly shortened from 3.31 s to 1.87 s,and the wastewater can be quickly discharged into the wastewater tank. When the three toilets work at the same time,the negative pressure in the wastewater pipeline will be reduced,and the flow rate of different cross sections will decrease by 66.5% on average,the toilet close to the wastewater tank will reduce the discharge efficiency of the farthest toilet,resulting in the wastewater cannot be discharged quickly. When the flushing time of toilet close to wastewater tank is adjusted to 2 s,and the farthest toilet needs to be opened separately,the wastewater in the farthest toilet can be fully discharged into the wastewater tank.Key words:civil aircraft;multi-phase flow;numerical simulation;wastewater system;toilet