Impact of Screens Around Bearings on the Flow and Heat Transfer in the Vent and Scavenge Oil Pipes in Bearing Chambers

Flouros, Michael; Cottier, Francois

doi:10.1115/1.4002153

Cited by 4 publications

(1 citation statement)

References 18 publications

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“…Porous screens introduced around the bearing would reduce the power loss considerably, by reducing droplet–droplet interactions and droplet-bearing chamber wall interactions . A further research indicates that although the screens reduce the parasitic losses and vent protrusion reduces the oil flow to the air–oil separator, the high-temperature problems caused by the oil flow distribution may lead to malfunctions in the engine’s lube system . In addition, sealing has an impact on the air–oil two-phase flow and heat-transfer performance. − Compared to the vent pipe, the scavenge pipe carries away most of the oil from the bearing chamber.…”

Section: Introductionmentioning

confidence: 99%

Influences of the Geometry of the Scavenge Pipe on the Air–Oil Two-Phase Flow and Heat Transfer in an Aero-Engine Bearing Chamber

Fang

Wang

et al. 2019

ACS Omega

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In order to improve the characteristics of the air–oil two-phase flow and heat transfer in the scavenge pipe of an aero-engine bearing chamber, this paper presents several scavenge pipes with different cross-sectional geometries, by numerically investigating the processes of the air–oil two-phase flow and heat transfer, in comparison to a circular pipe. The findings indicate that the tripetal cross-section shows the best heat-transfer effect, while the four-petal cross-section has the lowest flow resistance. Under the same working condition and the equal wetted perimeter, the tripetal cross-section has an 8.8% higher heat-transfer effect than the circular section, while the four-petal cross-section has a 28.6% lower flow resistance than the circular; under the equal cross-sectional area, the tripetal cross-section has a 9.1% higher heat-transfer effect than the circular section, while the four-petal cross-section has a 23.6% lower flow resistance than the circular; under the equal hydraulic diameter, the tripetal cross-section has a 9.2% higher heat-transfer effect than the circular section, while the four-petal cross-section has a 21.9% lower flow resistance than the circular. Taking both the heat transfer and flow resistance into consideration, the four-petal cross-section exhibits the best comprehensive performance, with the comprehensive performance coefficient decreasing with the increase of oil inlet velocity and rising with the increase of air inlet velocity.

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Section: Introductionmentioning

confidence: 99%

Influences of the Geometry of the Scavenge Pipe on the Air–Oil Two-Phase Flow and Heat Transfer in an Aero-Engine Bearing Chamber

Fang

Wang

et al. 2019

ACS Omega

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Research on the air–oil two-phase flow regime in an aeroengine bearing chamber based on Hilbert–Huang transform

Fang

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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The development of aeroengines toward a lighter and compact structure has put forward a stringent requirement on the lubrication systems, especially on the bearing chambers which contain complex air–oil two-phase fluids. Understanding the flow characteristics is of considerable significance to ensure the cooling and lubrication effect and to improve the working reliability of the aeroengine. Hilbert–Huang transform (HHT) was used to analyze the spectral characteristics of the pressure signals in the bearing chamber, in order to establish the correlation between the energy indicator k and the flow regime. The influences of the operating conditions and lubricant physical properties on the flow regime were discussed. The findings indicate that this approach can distinguish two typical flow regimes in the bearing chamber. With the increase of oil inflow and the decrease of draft speed, the flow regime changes from homogeneous flow to stratified flow, and k shifts from high-frequency band to low-frequency band. At the same lubricant mass inflow, k shifts from low-frequency band to high-frequency band with the increase of lubricant density, and the oil film on the wall becomes thinner. As the viscosity increases, the flow resistance grows and more oil accumulates on the wall. The flow regime converts from homogeneous flow to stratified flow, with k shifting from high-frequency band to low-frequency band. In addition, higher surface tension will cause more oil agglomeration, which results in less stable two-phase flow with irregular and uneven distribution of the oil on the wall.

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Simulation of Unsteady Flows of Oil/Gas in the Ventless Bearing Chamber of an Aero-Engine

Wang

2022

Aerospace

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The unsteady motion behavior of oil/gas two-phase flow in a novel ventless bearing chamber has significant impacts on the lubrication and heat transfer efficiency of bearings due to the various advantages of lower pressure levels and weaker rotating airflow effects. In this paper, the unsteady motion behavior of oil/gas two-phase flow in a ventless aero-engine bearing chamber is investigated by three-dimensional numerical simulation through the volume of fluid (VOF) method, and the numerical method is verified using published experimental data. The flow characteristics of oil/gas two-phase in the secondary flow and three-dimensional flow are investigated. The results show the evolution of vortices and the transition of the driving mode in the unsteady motion of oil/gas two-phase flow, and a criterion for the shift of the driving mode at different rotor speeds is proposed. As the rotation speed increases, the variation trend of the velocity field and pressure field of oil/gas two-phase flow is consistent, and the accumulation region of oil becomes inconspicuous. The results indicate a reference for enhancing the performance of lubrication systems for aero-engines.

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Impact of Screens Around Bearings on the Flow and Heat Transfer in the Vent and Scavenge Oil Pipes in Bearing Chambers

Cited by 4 publications

References 18 publications

Influences of the Geometry of the Scavenge Pipe on the Air–Oil Two-Phase Flow and Heat Transfer in an Aero-Engine Bearing Chamber

Influences of the Geometry of the Scavenge Pipe on the Air–Oil Two-Phase Flow and Heat Transfer in an Aero-Engine Bearing Chamber

Research on the air–oil two-phase flow regime in an aeroengine bearing chamber based on Hilbert–Huang transform

Simulation of Unsteady Flows of Oil/Gas in the Ventless Bearing Chamber of an Aero-Engine

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