Investigation On Leakage Losses And Heat Transfer In A Typical Labyrinth Seal During Wear Process

Aero-engine will experience start,idle,cruise or emergency parking conditions in actual use,which aggravate the phenomenon of vibration directly or indirectly.Labyrinth seal is an important part of the second-flow system,which often operated in high temperature environment,thermal expansion and creep generally reduces the gap futher.Therefore,the seal will appear different degrees of wear and leakage change after a long time period,thus affecting the engine's second-flow system.This paper studied the contact behavior between rotor and stator in Labyrinth seal,evaluated its seal performance change,which is important to Labrinth seal design,operation and maintenance in both theoretical and actual use.Primarily,to predict the wear process and its influence on leakage,this paper calculated the leakage and heat transfer in a 0.15mm-clearance labyrinth with eccentric and rotation conditions,analyze the influence of rotating speed and eccentricity on leakage coefficient and heat transfer coefficient.Results show that the eccentricity cause the circumferential gap uneven but doesn't influence overall leakage,the rotation effect is determined by rotation Ta Number and the value of Ta/re,increase in Ta resulted decrease in leakage coefficient,increase in Ta/Re resulted increase in heattransfer coefficient at stator.Followed by the simulation of steel-copper seal rubbing process using explicit dynamics module in ABAQUS,Johnson-cook material model(constitutive and failure model)was choosen,then calculate rubbing process and surface change under the condition of different rotation speed and incrusion speed with adiabatic\heattransfer boundary.Calculation shows that heat transfer had little effect on the rubbing shape while rotation speed and incrusion speed effect most.The increase of rotation speed induces a decreas of maxium normal force,when the incrusion speed increase,the maxium normal interaction force increase.Finally,sealing performance change is calculated based on three typical rubbing grooves.Results show that,when labyrinth tooth tip does not change while causing rubbing groove only,the overall leakage coefficient change is related to groove shape and clearance.Among the three kind of grooves,groove with deformation sharp reduce the leakage coefficient up to 15%-23% and perform best.All the research above develop a new simulation approach to understand the process of rubbing and its leakage performance change in Labyrinth seal.