Research On The Numerical Simulation Methods For The Gas Flow And Oil-Gas Separation Of Honeycomb Breather

In recent years, some domestic and overseas research institutions strived to continuouslyimprove the structure of the shaft center breather so that it could have a higher oil-gasseparation efficiency. In this paper, a honeycomb structure is arranged as a filter element inthe inlet of breathers, its advantages of larger specific surface area, lower flow resistance andadjustable structure parameters are used to improve separation efficiency of the shaft centerbreather on Aero-engine, and then obtain good separation performance.In this paper, calculating fluid dynamics (CFD) method is utilized for analyzing processof the flow and oil-gas separation in honeycomb structure of the breather so as to establishappropriate computing models. During this numerical calculation, k-ω turbulence model isused to simulate the honeycomb internal flow resistance characteristics, Discrete Phase Modelis used to simulate the particle track, so as to get particles’ motion and separationcharacteristics when they pass through the honeycomb structure.By calculating, Some characteristic parameters of this specific honeycomb structure suchas viscous resistance and inertial resistance coefficient are obtained to complete establishmentof the porous media model. Calculation results of this two-phase flow show that particlediameters and rotational speed of ventilators are the main factors, which can determinewhether particles can be separated or not. In same rotation speed, particles which havedifferent velocity vectors possess the same critical diameter and approximate separation effectwhen they leave the honeycomb area to its exit. And separation efficiency and particlediameters keep a linear relationship. The major separation mechanism is inertial collision. Indifferent rotation speeds, separated particles have different critical diameters and particle sizedistributions on the outlet of the honeycomb. A large number of analytical and statisticalresults show that the particles with different sizes in all directions have approximately thesame velocity distribution-Gaussian distribution when they leave the honeycomb area. In addition, according to the calculation results, this paper designed using User DefinedFunctions to give the corresponding particle size and velocity distribution, therefore thecorresponding oil-gas separation computing model in this honeycombarea is established.Optimization results show that, compared with the former breather, honeycomb structuremakes the radial hole become main pressure loss section. The study makes new explorationsboth in performance optimization of shaft center breather and the choice of filter elements, thecalculated results for the improvement of the experimental equipment of shaft center breatherpossess some significance.