Oil Droplet Motion Considering Breakup in an Aeroengine Bearing Chamber

Chen, Bin; Chen, Guo Ding; Shen, Xiaolong

doi:10.4028/www.scientific.net/amr.199-200.638

Cited by 1 publication

(7 citation statements)

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“…Some droplets can travel suspended within the convective air before they escape through the vent lines (Farrall et al, 2006); others can splash onto the walls of the chamber (Peduto, 2015) or might break up before coming into contact with the walls. In both splashing and breakup, there is the formation of smaller droplets called secondary droplets (Chen et al, 2011a), as indicated schematically in Figure 2.1.…”

Section: Oil Droplets In Bearing Chambersmentioning

confidence: 99%

“…Henceforth, the secondary droplets' size distribution can be determined by the Sauter mean diameter (SMD) and mass median diameter (MMD). The secondary droplet diameter is given by Chen et al (2011a) as follows:…”

Section: Droplet Break-up and Deformationmentioning

confidence: 99%

“…One of these might be the interaction between droplets, as well as air-droplet interaction (Adeniyi, 2015). Additionally, the droplet can break up during its flight (Chen et al, 2011a). Furthermore, the temperature of the droplet can increase due to the long residence time in the core flow (Sun et al, 2016b).…”

Section: Oil Droplet Heat Transfer and Mass Transfer In Bearing Chambersmentioning

confidence: 99%

“…The two-phase flow inside bearing chambers has been studied by two main research groups, the Gas Turbine and Transmission Research Centre (G2TRC) at the University of Nottingham and the Karlsruhe Institute of Technology (KIT) in Germany, who studied the thin film formation and droplet-film interaction (Kakimpa et al, 2014, Peduto, 2015, the flow of isothermal droplets in bearing chambers (Chen et al, 2011a, Farrall et al, 2007, Farrall et al, 2006, Peduto, 2015 and the heat transfer mechanisms between the oil droplets and the surrounding air (Adeniyi, 2015, Rosenlieb, 1978, Sun et al, 2016a, Sun et al, 2016b, with one historical paper and some recent Chinese contributions from outside these groups. However, the evaporation process and its effect on the performance of the chamber lubrication and thermal management have received little to no attention.…”

Section: Introductionmentioning

confidence: 99%

“…Other research has presented the analysis of droplet distribution and particle tracking , Farrall, 2000, Simmons et al, 2002, Farrall et al, 2006, Chen et al, 2011a, Chen et al, 2011b, Tkaczyk and Morvan, 2011, Adeniyi et al, 2014, as well as the formation of secondary droplets after impingement onto the chamber wall (Farrall et al, 2007, Williams, 2009, Chen et al, 2011b, Wang et al, 2011, Adeniyi, 2015, Peduto, 2015. Many of these studies have been undertaken at the University of Nottingham.…”

Section: Introductionmentioning

confidence: 99%

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Modelling Droplet Heat and Mass Transfer in Aero-Engine Bearing Chambers

Arcila

Morvan

Simmons

et al. 2019

Volume 2C: Turbomachinery

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The oil inside aeroengine bearing chambers can be found in many forms, including droplets which interact with the core airflow. The ability to model such bearing chambers computationally is desirable and thus a better understanding of the evaporation process of oil droplets is of great interest. Previous studies have analyzed the flow of isothermal droplets in bearing chambers. However, further investigation is needed into the heating of droplets in the highly rotating core region. This will enable designers to evaluate the behavior of droplets in a chamber and the likelihood that they will evaporate. The aim of this research is to analyze the oil droplet evaporation process under aeroengine bearing chamber representative conditions. An ultimate goal is the ability to predict the oil-air heat and mass transfer in the core flow region, as well as to develop an understanding of the flow inside a droplet, and how this affects evaporation. This latter is important as it has not been studied before. This paper presents the results of a numerical study of the evaporation process of a single droplet under bearing chamber temperature and air flow conditions. The two-phase flow is simulated using ANSYS Fluent with the volume of fluid approach and the evaporation process with the “D−square law”. First, the modelling approach is validated against previous experimental and numerical analysis of fuel droplets in an air flow with heat transfer. The simulation results were in excellent agreement with a benchmarking data set. The validated approach is then applied for investigation to smaller, bearing chamber representative droplets of an oil base stock used in jet engines. The oil evaporation rate was quantified as well as the evolution of droplet diameter, which revealed the effect of different air velocities and temperatures on the droplet. The extent to which evaporation rate increased with air velocity and temperature is quantified. It is concluded that droplets of initial diameters less than 200μm that remain in the chamber core region for more than 0.3s are likely to evaporate completely. This study allows us to estimate droplet heat and mass transfer and the associated phase change in a bearing chamber. It also provides best practice to predict the performance of small droplets under the effects of high temperature and velocity convective air flows. In future work this methodology will be applied in simulations in a representative bearing chamber to predict how the cooling process is affected by oil evaporation.

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Section: Oil Droplets In Bearing Chambersmentioning

confidence: 99%

Section: Droplet Break-up and Deformationmentioning

confidence: 99%