Dynamic Analysis Of Civil Aircraft Water Wastewater System Under Fluid-structure Interaction

The civil water wastewater system is an indispensable part of the airborne equipment,and its dynamic vibration is directly related to the normal use of the entire water supply and drainage system.Under the excitation of the aircraft's external load and internal flow,the water and wastewater pipelines and the tank-like structure are prone to excessive vibration,which in turn induces structural failure.Therefore,it is necessary to carry out simulation research on the fluid-structure coupling dynamics of the civil water and wastewater system in order to provide data support and technical guidance for system dynamics analysis,optimization and system installation.In this paper,numerical analysis methods such as structural finite element,computational fluid dynamics and smooth particle fluid dynamics are used.The fluid-structure coupling dynamics is the main theoretical basis.The ANSYS CFX structure and flow field coupling solving tools are used to simulate and analyze the dynamic characteristics of the water and wastewater pipelines and the storage box structure under fluid-structure coupling.For the water supply pipeline with only one-phase flow,the influence of fluid-structure coupling on the inherent modal properties of the pipelines are studied.The vibration response characteristics of the pipeline under the factors of fluid pulsation,supporting load and water hammer after valve closed are studied.For the wastewater pipelines with gas-liquid two-phase flow,the pipeline impact response under different wastewater flushing water volumes and different flight heights is analyzed and analyzed,and the distribution of the waste water pipeline clamps is rationally distributed and optimized for vibration.For the tank structure under water impact,combined with the FEM-SPH coupling analysis method,uses LS-DYNA analysis software to simulate the free surface sloshing of the liquid tank under the impact and rotating load and the dynamic stress response of the tank,and the studies about the effects of different sloshing excitation frequency and tank filling ratio on the sloshing dynamics of the structure are made,and finally an anti-sway design is carried out to prevent the water sloshing.