Study On Oil-Gas Two-Phase Flow And Heat Transfer Characteristics Of Aeroengine Bearings

Aiming at the problem of oil leakage in the lubrication of inter-shaft bearings of a certain type of aero-engine lubricating system,this paper conducts research on the flow and heat transfer characteristics of this type of aero-engine inter-shaft bearing and oil collecting structure.A multiphase flow computational fluid dynamics method was used to establish the flow and heat transfer numerical calculation model of three parts,namely the oil-sharing structure,the oil-collecting structure,and the inter-shaft bearing,using the periodic characteristics of the bearing oil supply structure.The oil-air two-phase The flow was calculated using a VOF model,and the two-phase flow field and oil distribution in the oil-collecting structure and bearings were obtained.The movement of the oil was analyzed and the cause of the oil leakage was found.The research results have important reference value for improving oil collection efficiency and improving bearing lubrication.The calculation results of the oil-sharing structure and the oil-collecting structure show that the oil distribution is uneven among the 11 radial oil holes distributed circumferentially on the collector,but the flow is similar.In the oil collecting structure,the oil and air form a countercurrent flow and a vortex ring.The reason for the oil leakage is mainly that the oil droplet particles splashed after the oil column impacts the wall of the cage are brought into the dam and the collector by the vortex The gap between the two sides is then thrown out into the bearing cavity,resulting in a reduction in oil collection efficiency.The calculation results show that oil collection efficiency has nothing to do with oil flow.The slip-grid technique is used for the calculation of the two-phase flow for the lubrication of the bearings between the shafts.Oil forms complex swirls in the inter-shaft bearings.The bearing cage,which also serves as an oil-collecting structure,allows more oil to be blocked and stays in the inner ring first,and flows to the outer ring under the action of centrifugal force and tangential friction on the rolling body wall surface.The gap between the rolling element and the front cross member of the cage is a dead zone for oil flow.The engineering method was used to calculate the heat generation coefficient and forced convective heat transfer coefficient of the bearings.The calculation results show that the frictional heat generation between the rolling elements and the cage beam is the highest.Finally,based on the calculation results of the flow field of the inter-shaft bearing and the results of thermal analysis engineering,a numerical calculation scheme of the temperature field of the inter-shaft bearing is proposed.