Investigation Of A Type Of Inertial Particle Separator Based On Surfaces With Different Rebounding Characteristics

Helicopters inevitably works in some harsh environments like desert,beach,and the inhaled air by engine might contain sand which will cause a significant decrease to its performance.To avoid this great disadvantage,the air-cleaning systems are necessary for helicopters.Vaneless inlet particle separators,which are highly integrated with the intake systems,are a type of advanced protective devices which has great advantages on weight and aerodynamic performance.However,aerodynamic performance and separate efficiency usually cannot be increased at the same time for IPS.Therefore,a new kind of vaneless IPS with nonuniform surface materials was designed in this study,and detail numerical study about it was also done,aiming at providing a method for the design of high-performance inertial particle separators.Firstly,the analysis of air flow filed inside a typical vaneless IPS was done by numerical method.Base on that,the movement of sand in the vaneless IPS were tracked and categorized.And three basic modes of the trajectories of large particles,which are dominated by rebound on the wall were studied on focus.Then the difference of rebounding characters of sand on four different materials namely,2024 aluminum alloy,7020 rubber,45 steel alloy and AM355 steel are analyzed.Then these four materials were applied on the wall of vaneless inlet particle separator,and the trajectory of sand inside these four vaneless IPS was get.Finally,taking full advantage of the differences of rebound characteristics on different materials wall,an exploratory study on the trajectory organizing method based on the conception of changing the wall material of vaneless IPS was carefully conducted.The results show that: by specially designing the surface material of the windward side of the bump as well as the aft part of the outer wall,the separation efficiency of the AC dust and C-spec.can be respectively raised by 7% and 24% without any total-pressure penalty,which means the separation efficiency of the separator is significantly increased.Finally,by combination of changing the geometry and altering the surface materials,a new design method of IPS which has high separation efficiency and high aerodynamic performance was developed and analyzed.