The Analysis Of Flow Field Characteristics And Structure Optimization For Dynamic Pressure Oil-gas Separator

Aeroengine lubricating oil system always mixes a certain amount of gas under normal operating conditions, which would adversely affect the system's safety. The dynamic pressure oil-gas separator is an important component for aviation engine lubricating oil system to eliminate gas. But under certain oil-gas flow rate, the dynamic pressure oil-gas separator doesn't work well and therefore it needs to be optimized.In this paper, research was done for dynamic pressure oil-gas separator which is using in the aviation engine lubricating oil system. The structure was simplified and the fluid domain model was established:helical blade with initial angle of 90 o, circular tangential inlet three-dimensional model; helical blade with initial angle of 90 o, rectangular tangential inlet three-dimensional model; rectangular tangential inlet three-dimensional model without helical blade.Before numerical simulation work, the multiphase flow model (VOF) and the Reynolds stress model (RSM) was selected in this article due to strong cyclone in the separator and the big oil and gas flow volume characteristics.Then, computational fluid dynamics software Fluent was used to solve the flow field of the dynamic pressure oil-gas separator of original model(helical blade with initial angle of 90 o, circular tangential inlet) and the velocity and pressure field was analyzed. And then for the original model, the flow field was simulated when the oil-gas volume ratio was 7:3,6:4 and 5:5,as well as the oil-gas inlet flow rate was 30L/min and 50 L/min. The simulation results indicates that the separator structure needs to be improved.On the basis of work done above, helical blade with initial angle of 45 o, circular tangential inlet three-dimensional separator model and rectangular tangential inlet three-dimensional model without helical blade separator model was simulated while the oil-gas volume ratio was 1:1 and the oil-gas inlet flow rate was 50L/min. The simulation results shows, for the particular working condition as above, the helical blade is bad for the oil-gas separation; the rectangular tangential inlet is conducive to he swirling motion of oil-gas; oil-gas sepator without a helical blade has better separation result; the inlet and outlet pressure drop was 2516.895Pa which meets the system requirements.